Easy Media profiling guide

5/24/2018 Easy Media profiling guide

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EasyMediaAddendum to the Reference Manual

Caldera V9

23/07/2013

Caldera 2011Caldera and all Caldera products mentioned in this publication are trademarks of Caldera


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E A S Y M E D I A T A B L E O F C O N T E N T S

23/07/2013 EasyMedia Page i

Table of contents

EasyMedia Print ................................................................................................................ 1Overview of the calibration process ........................................................................................ 1Creating a Media project ........................................................................................................ 3

Selecting the printer ................................. ................................... .................................. ........... 3Creating a new media ................................................ .................................. ............................ 5Setting up the print parameters ................................. .................................. ............................. 6The Project Manager ................................. ................................... .................................. ........... 7

Ink Transitions ....................................................................................................................... 9Overview .................................. ................................... .................................. ........................... 9

Linearization .........................................................................................................................11Overview .................................. ................................... .................................. ......................... 11Running the wizard........................................................... .................................. .................... 13

Initialization ................................... .................................. ................................... ........ 13Selecting/Printing/Measuring the target ................................ ................................... 14

Building the linearization curves ............................................................ ................................. 15The Pmax Editor in Spectral mode ............................................. ................................. 15The Pmax Editor in Density mode .................................. .................................. ........... 20Analyzing a density curve in CMYKcm .................................. .................................. ..... 22The Curves editor ................................ .................................. .................................. .... 24

Printing a test target .................................. .................................. ................................... ........ 24Ink limiting ...........................................................................................................................26

Overview .................................. ................................... .................................. ......................... 26Running the wizard........................................................... .................................. .................... 28

Initialization ................................... .................................. ................................... ........ 28Selecting and printing the target .......................................................... ...................... 29

Setting up the Ink Limit .................................. .................................. ................................... ... 30Printing a test target .................................. .................................. ................................... ........ 32

Profiling................................................................................................................................32Overview .................................. ................................... .................................. ......................... 32Running the wizard........................................................... .................................. .................... 34

Initialization ................................... .................................. ................................... ........ 34Selecting the target ................................................... .................................. ............... 35Printing the target .............................. .................................. .................................. .... 36


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Measuring the target ............................... ................................... ................................ 37Building the profile .......................................................... ................................... .................... 38

The main profiling options .................................. .................................. ...................... 38The separation options ............................ .................................. ................................. 40Computing the profile .............................. .................................. ................................. 41The profile statistics ................................. ................................... ................................ 42

Printing a test target .................................. .................................. ................................... ........ 43Finishing the project .............................................................................................................44Advanced topics ....................................................................................................................46

Printer's state, and choosing the right parameters ............................... .................................. 46Ink transitions ................................. .................................. ................................... ................... 53Transition curves .................................. ................................... .................................. .............. 55Total ink limiting .................................. ................................... .................................. .............. 56Editing a project ............................. ................................... .................................. .................... 59Media patches ............................................................ .................................. .......................... 61

Creating a media patch .................................. .................................. ........................... 62Installing a media patch ............................................................ ................................. 63

Importing calibration files ................................................ .................................. ..................... 64Importing measure files .................................. ................................... .................................. ... 66The measuring devices .......................................................... .................................. ............... 68

Barbieri Spectro LFP ................................. .................................. ................................. 68Barbieri SpectroSwing .............................. ................................... ................................ 69Caldera TotalColor ................................................ ................................... .................... 69Caldera Swing ............................... ................................... .................................. ......... 69Xrite / GretagMacbeth EyeOne ................................ ................................... ................ 69Xrite / GretagMacbeth EyeOne IO ............ .................................. .................................. 69Xrite DTP-41 ................................... .................................. ................................... ........ 69GretagMacbeth Spectroscan................................................. ................................... .... 69GretagMacbeth SpectroLino ............... .................................. ................................... .... 70Xrite DTP-32 ................................... .................................. ................................... ........ 70Xrite DTP-34 ................................... .................................. ................................... ........ 70

FAQ (Frequently Asked Questions) .........................................................................................70EasyMedia Monitors .........................................................................................................75

Choosing the project .............................................................................................................75Selecting the operation .........................................................................................................76Choosing the procedure.........................................................................................................77Selecting the type of monitor ................................................................................................78Selecting the reference target ...............................................................................................78Choosing the colorimeter ......................................................................................................79


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Calibrating the colorimeter....................................................................................................81Measurements ......................................................................................................................81Profile size ............................................................................................................................83Viewing the profile ...............................................................................................................83


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E A S Y M E D I A P R I N T

23/07/2013 EasyMedia Page 1

EasyMedia Print

his addendum document deals with the EasyMediacomponent of the Calderasoftware. It will explain how to use it to properly calibrate the colors for all yourprinting jobs.

Overview of the calibration process

A little bit of terminology to begin with: the word calibration, when applied to agraphic device, normally denotes the operation of putting the device into a stable,reproducible state (with a printer, for example, it should involve cleaning the heads,

printing a noozle test, etc.).

When applied to a Media (here as well as in the rest of the Reference Manual, wecall mediaany material that could be used for digital printing), it does not seem tomean anything: what would you do with a media to put it in a stable state? So, itusually implies everything that is needed in order to print correctly on ithowever,please note that even in that extended meaning, it is a clear abuse of language,because it is not only the media, but also the rest of the material (printer and inks),and the software, and the software settings, and many other things, that areinvolved in the print process.

So, in fact, it is neither a calibration nor a media; nevertheless we will adopt in thismanual the usual terminology and call the whole task a media calibration (or,sometimes, just a calibration, if the meaning is understandable enough in context)1.

So from now on, calibrating means everything you need to do to print correctly onyour media. But before starting the job, you must first create a Media Project. Amedia project is a combination of settings that makes a print configuration unique. Itis defined by a printer, a media, a printing mode (CMYK, CMYKcm, etc.), a resolution,and for certain printers a printing quality. All these parameters need to be definedbefore you begin the calibration. How to do that is detailed in chapter 2, Creating a

Media Project.

Once you have created the project, you will be able to access the Project Manager,which controls all the steps of the calibration process. In EasyMedia, this process ismade of three main steps:

1An alternative would be a media profiling, but this would also create confusion with the building of theICC profile, which is just one of the steps involved


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1. Setting up the InkTransitionparameters, to define the way the Light andDark inks will be used (if your printer does not have light inks, this step will ofcourse be skipped). This step is described in chapter 3, Ink Transitions.

2. Setting up the Linearization, which is divided into two sub-steps: the first is thelinearization itself (curves and individual ink limitation for each ink, sometimesknown as ink restrictions), and the second is the global ink limitation. This stepis described in chapter 4, Linearization, and chapter 5, Ink Limiting.

3. Building an ICC Profile (or just Profiling) which will allow you to use colormanagement with your media. This step is described in chapter 6, Profiling.

Each of these steps is controlled by a specialized wizard. The basic process is asfollows (with some variants, depending on the exact step):

Select a target. Print the target. Measure the print. Set up the calibration parameters. Select and print a test target. Validate the result or modify the parameters.

This process is not entirely automated. You will have to take certain decisions here,because media calibration is not an exact science. EasyMedia will always suggest yousome reasonable values, based on the measurement of the targets, but in manycases, you will have to deviate from these values, and make your own choices.

Finally, the Project Managerwill allow you to save the project files, as described inchapter VII, and thus to use your media in your usual Print Workflow.

NOTE:Even if your printer does not have light inks (or if you don't want to use them),you should strictly follow the order of the steps presented in this tutorial, and read

the chapter 3 entirely. This is because some of the procedures (e.g. printing,measuring the targets...) that are common to all the steps of the calibration areexplained and detailed in this chapter only, in order to avoid text repetitions


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Creating a Media project

Selecting the printer

If it is not already done, open EasyMedia. Then select the Printericon, and click theNextbutton.


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Select your printer and click the Nextbutton again.


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Creating a new media

The Mediawindow displays the list of available medias for your printer and, for each ofthem, the number of Projects (i.e. Print Configurations) already created. You can either

select an existing media for your Project, or create a new one with the Newbutton.

The parameters to set up for the new media are:

Its name (here, MyGlossyPaper). Optionally, its cost (for CostProof). Other settings, depending on the printer, in the Parameterstab.

If the Parameters tab is not greyed out, you also need to open this tab and selectsome initial values for your media. For example, for the Seiko ColorPainter64S, youwould have to select the temperature of the Heaters and the feed adjustment:

An Epson StylusPro9880 printer

Please note that these values can still be modified during the calibration; therefore,you can keep the default values at first.

Once all the parameters are set, click the OKbutton to finish creating the media, thenclick the Nextbutton to continue.


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Setting up the print parameters

If youve created a new media in the previous step, the list of available Projectsshould be empty. Click the New button to create a new one.

In the creation window, you will be prompted for the Printsettings to use in yourproject, which are just the printing mode (CMYK, CMYKcm, etc.) and the resolution.Select the configuration you want to calibrate2, and click the OK button.

Notes:

a) The specific parameters of the printer, such as the number of passes or theUni/Bidirectional value, cannot be set at this stage, and are not part of the settings ofthe Project. The reason is that normally, they do not affect the ink densities (though

sometimes they do, e.g. an Overprint parameter for some printers). However, youwill be able to set them up later during the calibration process.

b) You cannot select the screening in EasyMedia. The Stochastic screening will be usedfor all prints. However, the resulting calibration can also be used with the Errordiffusion screening, because both generate the same ink densities. As for the Halftonescreening, whose densities are very different, it is not currently supported by EasyMedia.If you want to make a profile for Halftones, you will have to use the normal Printinterface to print the targets, then go back toEasyMediato measure them.

c) You cannot create two different projects for the same configuration. If you need to

do that (e.g. to experiment, or to make a variant profile), you will have to create anew Media with a different name, then a Project for this media.

Once the Project is created, the window should look like this:

2This tutorial assumes that you have selected here a printing mode with Light Inks


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The Statusfield displays the string, which means that everything is still to bedone. Now click the Nextbutton to open the Project Manager and begin the calibrationprocess. Please take note that once you have entered the Project Manager, all theparameters that define your project (Media, resolution, and printing mode) are set uponce and for allyou won't be allowed to change them3and will be used

automatically for the printing of all targets, thus preventing you from making anymistake.

The Project Manager

The next window, the Status window, displays the current status of your project.

3 However, as already mentioned, you will be allowed to modify the Media parameters (e.g. heatertemperature)


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As said in chapter 1, there are three main steps to achieve the calibration: InkTransitions, Linearization (which is divided in two sub-steps), and Profiling. All thesettings for a given step are stored in a separate file (for the profile, it is a standardICC profile; for the other ones, it is just a plain text file). The Statuswindow displays asummary of the current state of the project, i.e. which steps have been achieved, andwhich ones remain to be performed. You can go back to this window at any stageduring the calibration process, to check the current status of the project, and possiblysave it. You can also exit the Project Manager(after saving) and resume the processlater exactly at the same stage.

Note that the three (or four) steps must be done exactly in that order. Furthermore,you normally should not modify anything in a given step when the next step hasbeen already performed (or, if you modify something, you should redo all thefollowing steps). The reason is that the settings of a given step are used to print thetargets of all the subsequent steps, thus they have an effect on how you (or

EasyMedia) analyze the results of the readings.


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Now click the Nextbutton again (or the Transitionbutton on the top of the statuswindow) to begin the calibration.

Ink Transitions

Overview

The aim of this step is to have your printer properly use the light and dark inks. Butfirst, without going into too many details, we will explain roughly how a CMYKcmdevice works, compared to a CMYK device.

Let's suppose you have a certain amount of Cyan to print, e.g. 20%. If you print inCMYK, there is no problem, and you will print 20% of Cyan. On the other hand, on aCMYKcm device, you will want to use the light cyan, because it will increase theapparent resolution of the print (in other words, it will reduce the graininess).

But what amount of light cyan will you print instead? 50%? 60%? This is one of thequestions you must answer in this step. Another question would be: in the lowdensities, you will want to use only light ink, but there is a certain point after whichyou will rather want to begin using dark cyan. Later on, there will be another point atwhich you may want to stop using light ink, i.e. printing with dark cyan only (youcertainly do not want to print on the same area, say, 90% of dark cyan and 50% oflight cyan, because there is a good chance it will only be a waste of ink).

So these two key points must be defined. After this, you must also define some

separation curves that will be used to separate an input Cyan into a Light and aDark component.


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Before explaining how you will do that, let's have a look at the shape these curveswill take:

As you can see, the introduction of dark cyan is here at 25%, and the light cyan stopsat 75%. Also in this example, you can see that before 25%, the light cyan curve is astraight line of a 2.0 slope, which means that to print a certain quantity of cyan, twicethis quantity of light cyan will be used.

In EasyMedia, you cannot freely set up these curves: it would be too complicated.Rather, the curves are computed according to the 3 parameters we have introduced:the initial slope of the light ink curve (which physically represents the ratiobetween the dark and the light ink, i.e. how much denser the dark ink is compared tothe light ink), the introduction point of the dark ink, and the stop point of the lightink. To define these parameters, you will be assisted by the InkTransitionWizardthat will make you print, measure, and analyze two targets: one printed with lightink only, and the other with dark ink only.


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Linearization

Overview

The goal of the linearization is to set up 4 curves, one per process ink, that the printdriver will use to transform input densities (as they appear in the image file, or asthey are generated by the Color Management System) into output densities, alsocalled ink densities, or printer densities. Here is an example of a set of curves:

If these curves would be applied on a print, the print driver would, for example,transform a patch of 4x50% into 4x25% (approximately), before screening andsending the dots to the printer.

If you look at these curves, you will note that an input cyan of 100% would be

printed only at 80% (approximately). This is called restrictingthe cyan. Setting thecorrect ink restrictions(or individual maximum amount of ink, as opposed to globalmaximum amount of ink) is in itself a sub-step of the linearization process, andprobably the most important one. The other one consists in determining the exactshape of the curve, between 0% and the maximum (also called Pmax).

There are many reasons why you would like to restrict the ink usage, and we willexplain some of them in the process. There are also many ways of defining theshape of the curves. Most of them are algorithmic, so you will not have to place allthe control points manually (though you can do it that way if you want). EasyMediaoffers a few different methods. Deciding which one to choose depends a lot uponwhether you want to use a Color Management System (i.e. ICC profiles) or not.


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If you want to use an ICC profile, then the linearization should only be thoughtas a preparatory step for printing a correct ICC target, i.e. a target where theink does not bleed, does not bend the paper, and where the patches coverthe widest gamut possible, as uniformly as possible. You should have no

particular expectation of the color given by 50% cyan, a combination of 100%cyan and 100% magenta, or any other combination, because there will be noway for you to print these values directly. Thus, the exact shape of thelinearization curve has little interest for you4.

If you want to print without an ICC profile, then the situation is different. Thelinearization curves will entirely determine the output of the print process, soyou need to be more careful. EasyMediacontains some predefined target-curves, defined by a dmax/dot gain couple for each ink. You will have toselect whichever standard fits to your print process, and you will also have to

run the trial-and-error method to set up a correct grey-balance (EasyMediadoesn't have any method to optimize the grey balance). Please also notethat you will have to read in (optical) density mode, so you need adensitometer, or a spectrophotometer-densitometer.

In this tutorial, we will cover both approaches, although with a focus on the first one,since using an ICC profile is the normal way to proceed in modern digital printing.Both require using the Wizard to print and measure a linearization target, so thebeginning is common to both methods.

4In case you are preparing a profile for proofing or for simulation, it is a little bit more complex than that:indeed, you would want to be able to optimize your linearization to match as closely as possible thesimulated or proofed gamut. EasyMediahas an included support for doing that, but this is an advanced topicthat will not be covered by this tutorial


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Running the wizard

Initialization

If you've completed the previous step (Ink Transitions), you should now be in themain menu of the linearization step. So check that the RunWizardoption is selected,and click the Nextbutton.

Note:If you want to save your Transition curves before going on (that may be a goodidea), you can click the Status button, then save the project and click theLinearizationbutton to get back to this window.


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Selecting/Printing/Measuring the target

These 3 steps have already been detailed in the previous chapter, so we will nowfocus on the specific aspects of the linearization.

Several targets are available. Again, which one to select depends a lot on yourmeasuring device. As for the sampling step, 5% is usually enough. We suggest usingthe CMYK target, 5% step with composite patches. This target contains a few 2-, 3-and even 4-color patches on the left side of the print (these go up to 400%). Thesepatches are not supposed to be measured, but they will give you a rough idea of theinking capacity of the media, which is often good to know in order to set up a correctlinearization.

Once you have selected the correct target, click the Nextbutton, then print the target

(please refer to the corresponding section in the Transitionchapter for all the detailsabout the print options). If you have selected a target with composite patches, andknow that your media will not support the highest densities, be careful to set up atleast a global ink clipping.

Once it is printed, you may need to wait some time until it is not only dry, but untilthe colors are stabilized, too, before measuring it. With certain types of inks, you mayhave the feeling that the print is dry, yet the colors are still changing. This stabilizingtime can go from nothing up to two or three days, depending on the model of theprinter and on the inks. Usually, however, it does not depend on the media, so youcan use the same drying time for all your prints (the printer manufacturer should

know it).


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As for which measurement mode to use to measure a Linearization target, spectralvs. density (supposing you can use both), it depends on your goal: if you want tobuild an ICC profile for your media, read in spectral mode. If you do not want to usean ICC profile and/or if you want to linearize with respect to a dotgain/dmax target,

then read in density mode.5

Building the linearization curves

After reading the linearization target, you will be able to set up the ink restrictionsand the linearization parameters in the Pmax Editor. Here, we will suppose first thatthe target was read in spectral mode; then we will explain the differences when it isread in density mode.

The Pmax Editor in Spectral mode

The graph displays the output density curves, as measured by thespectrophotometer. The input percentages are shown in abscissa, and the measured

5If you only have a densitometer, and want to use an ICC profile, you can measure the densities; it is notincompatible. However, you will probably need to have the profiling target measured by someone else,since you cannot read a profiling target with a densitometer


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densities in ordinate6. All the densities are displayed in relative mode, so the fourcurves go up to a maximum of 100%though 100% of black does not mean thesame as 100% of yellow, of course.

What you need to do in this window is to set up the maximum percentage you wantto use for each ink (it is labelled Pmax in the window). The Dmax value representsthe corresponding output density of the current Pmax. You can either enter directlythe Pmax values, or enter the Dmax, in which case the corresponding Pmax will beautomatically computed.

Moreover, if you click the Cyan button on the right of the window, you will haveaccess to control bars that allow you to graphically select (with the mouse) either thePmax or the Dmax.

So what is the optimum Pmax to select? Basically, it is the value above which there isno more significant increase in output density. In our example, it is obvious thatprinting 100% of cyan has no interest, because 90% already gives the same density.

6Please note that density here has nothing to do with optical density. It is a spectral density, i.e. somevalues derived from the Lab measures, according to a proprietary algorithm (there is no standard).


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Moreover, if your media does not support a high quantity of ink, restricting to 90% isa good idea: it will make the global ink limiting easier to perform.

By default, EasyMediawill select itself as Pmax the values that output a Dmax of

99% (you can click the Auto button to reset to the default values, if you havemodified them). This will optimize the potential gamut, and at the same timeprevents the use of too much ink. You may have many reasons, though, to raise thisvalue (sometimes) or to or lower it (often):

Visually check the printed patches. The measuring device will not detect mostof the problems caused by over-inking (bleeding, cockling, etc.), so if you seea problem with the Pmaxdetected by EasyMedia, you will have to lower it7.

Visually check that the ink completely covers the media at the selected Pmax.Although it is seldom, it may happen that some grain, such as the paperbeing seen through the ink, remains at 90% and not at 100%.

If you suspect that your media will not support much ink in combination, thenyou may slightly lower the Pmax. At that point, you should have a rough ideaof the Ink Limitation you will have to apply (especially if you printed thedefault linearization target, which contains combined patches). If, forexample, you think that your Ink Limit will be around 150%, then do notselect 100% for the four inks: this would lead to a very unbalanced gamut,and may cause some inconsistencies when building the profile. On the otherhand, if your media supports 300% or more, then go on and select the

highest Pmax. As a general rule, do not set any Pmax higher than theexpected Ink Limit divided by two8.

When you are ready, click the Nextbutton to compute the linearization curves.

NOTE:In spectral reading, EasyMediauses by default a straight linear target curve, whichmeans that if you print the linearization patches again with the linearization curvesapplied, and read this target in spectral mode, the output densities will be a straight line.However, it is possible to select a different target. Please see the FAQ for this.

Here are a few examples of problematic curves, and how to deal with them:

7Correcting the measurement errors is done on the linearization curves rather than on the measured curves. It is impossibleto modify the measures

8In EasyMedia, the global Ink Limit is expressed in ink densities (i.e. is applied after the linearization), so wespeak here of the samedensities. For more details, see the next chapter (Ink Limiting).


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A curve which is going down again for high densities shows a saturation, so youmust avoid this part of the curve.

A curve going upward quickly and then slowing down without saturationshows that after a given ink quantity, adding more ink does not really changethe resulting density. In this case, adding more ink would be just a waste, sowe will stop when the curve slows down.

A curve with a belly shows a lack of density resulting from too much lightink. If it is too pronounced, you must go back to the ink transitions, lower thelight ink ratio, and redo the linearization, including printing and measuring thetarget.

If the profile is done without light inks, the problem comes from a wrong balancebetween different ink dots (variable dot). In that case, if the printer has a dotgain adjustment (usually in the media parameters), you should try lowering theratio of small and medium dots; otherwise just go on with the profiling process.

A small belly can also be compensated by the transition process.


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"Belly" around 25 % Lack of density around 60 %

A curve with high densities in accordion (no apparent saturation) shows either asaturation which fooled the measurement device, or a measurement error due tomedia grain (canvas, textiles, some banners ).

In case of saturation, we advise just limiting before the problem if theproblem doesn't affect too low densities. However you can usually rely to thesmoothing done by the computation of correction curves.

If the media is particularly grainy or textured (textiles, canvas, PVC banner),or if the resolution is too low, we advise you to measure again using a wideraperture on the measuring device or selecting a multiple measure option.

For EyeOne and TotalColor targets, black lines separate the patches for yellowhigh densities. If they seem blurry or bleeding, it is a good indication that theink acceptance is somehow low.


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The Pmax Editor in Density mode

The editor looks quite the same for a density reading, except that the graph displaysby default the Optical Density data, whose curves are very different.

You can choose to display the DotAreavalues (in percentage) instead, by clickingthis option on the top of the window.


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The principle is the same when it comes to selecting the Pmax:you can directly enterthe percentage, or you can enter the density you want to reach, in the Dmaxfields.By default, EasyMediawill use a straight line as target, i.e. will try to match a densitycurve without any Dot Gain. If you want to select a Dot Gain, you must click the

Targetbutton, and select the Use Dmax/DotGain curve as targetoption.

In this window, you can set up both the Dmax and the Dot gainyou want to match(here, for example, the Web-Offset standard). Once again, when you change the Dmax,EasyMedia will automatically select the corresponding Pmax in the main window.

Please note that when you select this option, a second set of curves (the targetcurves) will be displayed in the editor. You can hide/show these curves with the

DisplayTargetbutton in the top right part of the window.


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Analyzing a density curve in CMYKcm

As it has been mentioned in the Overview of the Transition process, with propertransition curves, you should obtain the same type of curves as in CMYK mode.

However, they will most likely differ a little bit. A typical density curve made withlight and dark ink should look like this:

Note that the curve starts normally, then flattens a little bit between 25 and 50%,and gets back to the normal shape after 50%. This is due to the fact that the light inkdoes not provide a sufficient increase in density past 25%. Still, this is acceptable, andthe linearization can easily correct this artefact. Here is the resulting output curve:


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Now, lets consider the following output curve:

Here, the flattening effect is really marked, and you should not go on with thelinearization if you get such a curve. Instead, you should go back to the Transitioneditor(or to the Transition Wizard) and try to correct the problem, which is that thedark ink starts at too late a point. If you continue, you will end up with curves that

look as follows:

Note the jump around 75%, which will likely cause some problems on a gradation of cyan.


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The Curves editor

The next window displays the final linearization curves, as computed by EasyMediawith the Pmaxvalues and the requested target curves (if any).

Here you can still modify the curves by moving the control points. You can also clickthe Numberstoggle on the top left of the window, to examine and/or modify theexact values.

Normally, you should not modify the curves at that point, because they are the resultof measure and computation. However, you should inspect the placing of the controlpoints, in case there has been an obvious measurement error. For example, ifsuddenly the yellow curve were to decrease from 60% to 55%, and then increasesagain normally, you could move the failing control point manually.

Printing a test target

After clicking the Nextbutton, it will become possible for you to either validate thelinearization curves, or to print a test target, after which you will be able to modifythe curves (or maybe to go back to the PmaxEditor), in case something has gone


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wrong. The procedure is strictly identical to the one described in the previous chapter(Transition curves), so we wont detail everything here.

If you intend to build an ICC profile immediately after (or more exactly, after setting

up the Ink Limitation), there is no reason for you to print a test target now. As alreadysaid, you do not expect anything special for any ink combination. You do not expectany special grey balance, or the 100%M-100%Y combination to be a special red,because setting up the colors is the job of the ICC profile. If you want, you can print atarget with gradients to check that there is no obvious tonal discontinuity, but it isdifficult to judge visually. If you print a target that contains a CMY gradation, do notworry if it has a greenish or brownish cast: again, this does not have any importance.

On the other hand, if you want to print without any ICC profile, then the calibration isfinished, apart from the Ink Limitation. You now need to check that the outputmatches your expectation. In particular, you could print the Greyscale target to checkthe grey balance9.

Also, do not forget that you can load any TIFF file (from the target menu), or drag anddrop any image from the image bar, if you want to print your own custom test file.

9The greyscale target is a Greyscale TIFF file, not a CMYK. All the greys will be printed using equal quantitiesof C, M and Y (and no black at all). If it's not what you want to print, use another target


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Ink limiting

Overview

The next step consists in setting up the Ink Limit, or Global Maximum amount of ink.This consists in a single number (between 1% and 400%) that you will want to useas a maximum inking value for all the prints. The goal here is to avoid bleeding,cockling, or any other artefact caused by over-inking. The way the Ink Limit is used bythe print driver is that all pixels with a total ink value (in other words, the sum of the4 percentages) higher than this limit will be clipped, i.e. the percentages will belowered to reach exactly that limit.

As it has already been said, that step is normally included in the Linearization processin fact, this number is stored in the same file as the linearization curves. This is thereason why there are only 3 files in the Statuswindow. However, for clarity purposes, ithas been implemented as a different procedure. Moreover, to do it optimally, you needto know the individual ink restrictions. In reality, though, the two steps could be done inparallel, since they do not influence each other. So this is an exception to the rulementioned in the Calibration Overviewthat says that when you modify a setting in agiven step, it invalidates all the previous steps already completed.

A little bit of technical clarification is necessary there, because this may hurt what youhave learned from the calibration processes in other RIPs. In most of them, the InkLimit is expressed in linearized densities10, while in EasyMedia(and in the whole Printsystem of Caldera), it is expressed in ink densities. It is very important to understand

the difference, and in order to explain it, we will give you an example.

Lets suppose that we've set up the following linearization curves:

10These can also be called input densities. The expression linearized densities is somewhat confusing,because the linearization is applied to the input densities, so one may say as well that they are linearizedafter, and unlinearized before. However, it would be odd to speak of linearized densities when it comes toprinter densities, the latter being absolutely non linear


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As you can see, all the densities are approximately divided by two. Now, with an InkLimit expressed in ink densities, the potential maximum of the limit is approximately4x50% = 200%. But when it is expressed in input densities, it is still 400%. Theimportant point is that in Caldera software, the global ink clipping is applied after

linearization: so the global ink limit is defined in ink densities. This is a post-linearization clipping, while the other one is a pre-linearization clipping.

Both methods have advantages and disadvantages. The Pre-linearization clipping iseasier to understand, because the value of the limit is more stable (usually between300 and 400%), while it varies enormously in Post-linearization. On the other hand,with the Pre-linearization method, the linearization and the ink clipping must beimplemented as different steps in the calibration process. This is because 360% inPre-linearization, for example, does not have the same meaning if you change thelinearization curves, while 150% in Post-linearization is independent of the

linearization (it is a quantity of ink). So, you can use the same target for linearizationand ink limiting with the Post-linearization method, while with the other one youneed to print separate targets.

We also think that the Post-linearization method is more accurate, and accuracy isimportant here. You need to realize that, when we say that the ink limit is 250%,what we mean is that all combinations of CMYK higher than 250% are bad, and thatall the other combinations are good. This is of course greatly simplified, and itcertainly does not work that way (it is done this way so that the calibration processwont be too long and too complicated). At least, in Post-linearization, 250% is afixed quantity of ink, so one may hope that it will lead to the same problems (or lack

thereof) no matter what the underlying CMYK combination is. At the same time, withthe Pre-linearization method, 250% will lead, after linearization, to differentquantities of ink (unless the four curves are exactly the same, which is not veryusual), and does not correspond to any physical data related to the printer.

This being said, the process for setting up the Ink Limit is quite simple: it only requiresprinting a target, examining it, and deciding what the limit is. There is no measureinvolved (a measure cannot detect the problems caused by over-inking).


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Running the wizard

Initialization

Once you have finished the previous step (Linearization), you should normally findyourself in the main menu of the InkLimitprocess.

At that point, you could also use the Enter the limit manuallyoption, which allows

you to enter directly the ink limit value, without printing any target. Since there isnothing to measure, it is an option you will probably use sometimes, especially if youhave already printed composite patches in the linearization step. For the time being,select the wizard and click the Nextbutton.


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Selecting and printing the target

The default Ink Limit target is labelled Dynamic Target. It is an image that will begenerated on the fly by EasyMedia, and optimized for the current ink restrictions. Itlooks like the following:

Optimized for the current ink restrictions means that this image will not containpatches with a total inking greater than the sum of the 4 Pmax (which is, in our case,


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340%). Also, this image will not contain patches that are incompatible with therestrictions (for example, if the Pmax on both cyan and magenta is 90%, the Purebluepatch will be at 180%, and not at 200%).

The other targets are fixed, and, like this one, contain a density increase of 10% percolumn, with different ink combinations for each line. They may be helpful in certaincontextsfor example, if you absolutely need to know your Ink Limit in order to decideon the ink restrictions, or if your printer has a one day long drying time (in this case, youprobably would not want to waste a day just to be able to print the optimized target).

Whatever the target you decide to select, the process remains the same after that:click the Nextbutton, print the target (possibly with a clipping, since by definition thiskind of target contains a lot of high-density patches), and click the Nextbutton again.

Setting up the Ink Limit

Now you need to examine the target closely, and, proceeding from left to right, toidentify the location of the last column whose patches are all printed correctly. It isdifficult to list all the possible unwanted effects caused by over-inking, which differvery much depending on the printer and the media. Ink may bleed, bend thematerial in a number of different ways, not mix correctly, etc. So, inspect the targetcarefully, and look for any effect that you do not want to see on your final prints.

Here is an example of bleeding, although it is a little bit extreme:


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Once you have located your ink limit, enter the value in the field labelled Total InkLimit. As for the other option, always select Preserve black ink(the other one is forcompatibility with previous versions of the Caldera RIP).

At this point, you may realize that your Ink Limit is too low compared to the individualink restrictions you have previously set up. Remember the rule stated in the previouschapter: the ink limit should not be lower than twice the average of the four Pmaxvalues. If this is the case, go back to the linearization step, and lower the restrictions.After that, you can print the dynamic target again (or notit is not always useful).


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As usual, after you click the Nextbutton, you will be asked whether you want to printa test target or not. The so-called bleeding target may be useful to print.

This target contains some text elements, at different sizes, and with differentforegrounds/backgrounds. If you cannot read the smaller text, it means that there is aproblem in the ink limit, or in the ink restrictions, or even both. Whether this isimportant or not depends on your application. If it is likely to become a problem for you,you will need to lower the inking somewhere. This way, you will lose in ink density, andmaybe in gamut; therefore you need to find the correct compromise here.

Profiling

Overview

We are now reaching the last and decisive step of the calibration: building the ICCprofile. Please note immediately that, while everything else in EasyMediais free (itcomes with any Caldera product), computing an ICC profile requires licence keys. Ifyou do not have these keys, you will be able to go through all the steps (including


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printing and measuring the ICC targets), until you reach the last window, whichcomputes the profile. There, you will get an error message11.

Everything you did until now was only to make your printer use the inks in a proper

and optimized fashion. Everything was related to inks, and nothing to colors. The goalof the profiling is, simply said, to establish a mapping between all the colors thatexist in nature and the colors that are available in your printer (or, more exactly, inyour current print process, which includes the media and the print configuration, aswell as the current linearization and transition curves). Without detailing too much,this mapping is implemented as a look-up table from the LAB space (it is the space inwhich colors are measured by a spectrophotometer) to the CMYK space of the printer.

How is this table computed? The idea is quite simple:

Print a profiling target, which is an image containing a lot of patches. Measure this target with a spectrophotometer. From this measure, the CMYK

to LAB table is computedit's easy, since the CMYK values of the printedpatches are known in advance.

The LAB to CMYK table is computed as the inverse of the previous table.Of course, this is a huge simplification of all the computations involved. Especially,building the inverse of the CMYK to LAB table is very difficultthis operation is calledGamut Mapping, and there are lots of ways to do it. Besides, the majority of optionsavailable to build the ICC profiles are related to gamut mapping.

Here, you may want to ask whyoptions are available. Isn't ICC profiling supposed tobe the way to print exactcolors, without human intervention? The answer is that it isa little bit more complicated than that. This would be (almost) true for a perfectprinter that would cover the entire LAB gamut, i.e. be able to print all the possiblecolors. But in the facts, such a printer does not exist, and you are faced with twodifferent problems:

Out-of-gamut colors must be printed in a way or another. However, for agiven out-of-gamut color, there may be no obvious choice for which one is

the closest in the gamut of the printer.

There may be more than one way to print a given in-gamut color. Forexample, a neutral grey may usually be printed with more or less black ink.

Thus, here again, you will have to make choices, and retain the options that workbest for your media.

11 EasyMedia includes the LOGO engine from XRite, the same engine that is used in ProfileMaker, withexactly the same features. If you already own ProfileMaker(or any other Profiling Package), you will be ableto build the profiles with this package, then to import them into EasyMedia (the procedure is explainedbelow and in chapter 8, Importing calibration files)


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Running the wizard

Initialization

The process starts in the Profilingmain menu.

If you have an external ICC profile software and want to import a profile, selectLoad/Import an existing file, then see chapter 8 (Importing a calibration file);otherwise select RunWizard, and click the Nextbutton. Please note that even if youuse an external software, you will have to run the Wizard to begin with, at least toprint the ICC target, and possibly to measure it.


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Selecting the target

There are many types of targets available for profiling, and they vary considerably insize and in number of patches. The number of patches is very important for thequality of the profile; therefore, if you want a high-quality profile, select the targetthat has the highest number of patches, amongst those that are compatible withyour measurement device.

In this example, we will use the EyeOne standard target, which contains 320patches12. It is not many, but the measurement only takes a few minutes.

12We advise not using this target for a high quality profile.


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Printing the target

Here, you need to adjust the print parameters, then click Print to print the target(please refer to the Ink Transitions > Running the Wizard > Printing the targetssectionfor an explanation of all the options).

Be careful not to activate Ink Clippingat that point, because youll absolutely want touse the linearization and Ink Limit you have set up previously. Also, be careful torespect the drying time before measuring. For the previous steps, it is not absolutelynecessary, but for this one, it is.


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Measuring the target

Again, you can consult the chapter 2 for all the details about measuring a target withthe EyeOne.

Be careful: measuring an ICC target is much more difficult than measuring alinearization or transition target. There are more patches, so it takes longer, and you

won't notice if you scan the wrong stripwith a linearization target, if you scan theCyan instead of the Magenta, you will notice it immediately. Keep concentratedwhile scanning, and always make sure that you are scanning the appropriate strip.

Here as well, do not deactivate the double-reading, whatever the reason. Do notforget that you can scan from right to left or from left to right (EasyMediawill detectthe direction), so the fastest way to work is to scan in one direction for the firstreading, and in the other direction for the verification reading.

Even more than before, we advise checking again the spectrophotometer'sparameters, especially the aperture of the head. Most of the separation/linearization


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targets have wide patches that tolerate any aperture, whereas some profiling targets(2 mm for TotalColor) do not accept a wide aperture.

Building the profile

The main profiling options

After the reading, you will have to set up a few options to build the profile.

The ProfileSize is the approximate output size of the generated file. Thedefault is Medium(approximately 700 Kb). Raising it to Largemay slightlyimprove the profiles accuracy, if the linearization on the printer is well-done.

The Perceptualrenderingdetermines how the neutral (grey) colors are to berendered, in case the white of your media is not perfectly neutralwhich isusually the case. If you select Preserve grey axis, the profile will try tocompensate for the non-neutrality of the media, and greys will be printed asreally neutral, if possible. If you select Papergreyaxis, then the entire greyaxis will be shifted in the direction of the media white (for example, if you

use a green paper, the greys will be printed as green). This is the default,


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because our perception of neutrality depends a lot on the white of themedia13.

The Gamut Mapping makes available three variants for the mapping of theLAB values into the CMYK color space of the printer. This mainly concerns themapping of out-of-gamut colors, but may have an effect on the wholespectrum. It is very difficult to predict the effect of this setting, since itdepends a lot on the printer, the media, the inks, etc. The default is LOGOClassic. If rendering rich and bright colors (especially reds) is problematic, tryLOGO Colorful instead14.

The balance The Viewing Light Sourceallows you to set up the light source under which

your prints are to be viewedbecause of metamerism effects, colors usuallylooks different when seen under different light sources, e.g. the grey axismay look neutral under daylight, and exhibit a green cast under a fluorescentlight.For a general-purpose profile, always keep the CIE default, D50. Otherwise,select which one fits your needs, or open a Custom light source15.

You can come back to the default values using the Resetbutton.

13This setting does not affect the colorimetric rendering, nor the absolute rendering (the ICC specificationsrequire Paper grey axisin the first case, and Preserve grey axisin the second case, but nothing is specifiedfor the perceptual rendering).

14The Gamut Mapping option doeshave an effect on the Colorimetric and Absolute renderings, though farless important than in Perceptual rendering

15Here again, you need to have a spectral data measurement file to use this option, otherwise it will begreyed out.


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The separation options

The second (and last) set of options for the profiling concerns the Black Generation options.

These options determine how you want to use the inks to print neutral greys, andmainly how much black you want to use.

TheSeparation Methodis the base algorithm. You can select one of the four levelsof GCR(GCR4 using the more black ink, and GCR1 the less), or UCR(which uses evenless black ink than GCR). The two other options, No Blackand Max Black, will use noblack ink at all and a maximum amount of black, respectively. They should be usedfor very special purposes only.

The BlackStartvalue (expressed in %) is the percentage of C-M-Y above which youwant to introduce the black dots.

The MaxBlackvalue (expressed in %) is the amount of black you want to use foryour darkest composite black. It should normally always be set to 100%.

The MaxInkvalue (expressed in %) is the amount of ink (C+M+Y+K) you want touse for the darkest composite black. We recommend setting its value around 350%,though it depends a lot on the printer.


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Finally, the BlackPointvalues (on the right of the curves) define the componentsof the darkest composite black. Normally, you should not enter the values manually.Instead, EasyMediacomputes the Black Point by itself, when the Balanceoption ischecked. It uses the measurement made on the ICC target to compute the optimal

black point, taking into account your current MaxInkvalue.Finally, the separation curves displayed in the graph provide a quick overview of theway neutral greys will be generated with your profile. However, this is only anindication, and the final curves will probably differ a little bit.

Note that all the values in this window are expressed in input densityand not in inkdensity(see the discussion in the preceding chapter). Thus, for example, 400% asMaxInkcorrespond exactly to your total Ink Limit, and 100% of cyan in the BlackPointcorresponds to the cyan Pmaxset in the linearization step.

Computing the profile

Once you have set up all the options, click the Next button. EasyMedia will thenbegin to compute the profile.

This process may take a few minutes, after which some statistics about the profilewill be displayed.


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The profile statistics

In the left part of the window, a CMYK image is displayed. It is a soft-proof of whatyou would get if you were to print this image with the profile that has just beencomputed. If you click the Disable profile button, it will turn to a soft-proof of whatyou would get if you were to print it withoutthe profile. Therefore, the first thing youcan check here is if it is better with the profile, the second thing being if there is notany obvious problem regarding the colors (for example, a red that turns into blue

when you switch the profile on/off). Otherwise, if colors are different, it is absolutelynormal (they are probably darker without the profile).

If the colors look completely wrong, then it probably means that the target has beenincorrectly read. For example, the auto-positioning on the TotalColor may have failed,or you used reflexive mode instead of transmissive, etc.

In the right part of the window, some profile data is displayed: the creation date, thewhite point (in LAB) and the black point (both in perceptual and colorimetric mode).

In the lower part of the window, EasyMediadisplays some statistics about the profile,

which are supposed to be a rough indicator of its quality. The first number, Self-


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Gamut, measures the internal coherence of the profile: it is the average Delta-E16youwould get if you printed all the in-gamutcolors of the profile. In theory, this numbershould be zero (as per the definition of in-gamut colors17), but all the technicallimitations of the process (limitation in the amount of printed patches, limitation of

the profile size, etc.), make it so that usually, you will get a Delta-E between 1.0 and2.0. If you get more than 3.0, it means that there is likely a problem.

The second number,Gamut/Swop, is the average Delta-E of your profile comparedto the SWOP gamut. It is a very quick indicator of how well your media will renderSWOP colors. We insist on the fact that this simple number in itself does certainly notquantify all the complex aspects of gamut comparison. However, if you get a result of1.5 for a certain media, and then of 5.0 for another one, you can be almost certainthat the first is better than the second.


As with all the other steps, you now have the possibility to print a test target. Thisprint will go through the whole calibration process (transition, linearization andprofile), so it is really the final test for your media.

We will not explain the procedure here, since it has already been described in detailsin the previous chapters. Do not forget, too, that you can drag and drop an imagefrom the Caldera image bar to print your favourite target, in case it does not exist inTIFF.

Moreover, at that point, you could also save the project, and run the normal Printinterface to print your test target. In fact, you will have to do it this way if you wantto activate some advanced options of the Printmodule. In EasyMedia, the test printwill not process Spot Colors, for instance, and will print everything in Perceptualmode; if you want to print vectors in colorimetric mode (or disable ICC for vectors, asis sometimes done for test targets), you will have to use Print.

16A Delta-Eis a number measuring the difference between 2 colors in the LAB space. It should be as smallas possible.

17However, please note that the Black Generation options may somewhat restrict the theoritical gamut, ifyou do not use enough black


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Finishing the project

After the validation of the ICC profile, you should find yourself back to the Statuswindow.

Please note that the three fields are now filled with a file name. EasyMediaautomatically generates the file names (based on the printer's name, theabbreviation of the mediawhich is made of the upper characters and the numbersit contains, as well as of the other print settings). You can rename the files with the

Rename button, if you do not like them.

Note also that the status of the project is now Calibration Complete. The Modifiedlabelmeans that you need to save the project files to be able to use the media in the Printmodule. So click the button labelled Save Project to save the files.

You need not specify a directory into which to save the files, because EasyMediawillinstall them where they are supposed to be. This is an area where EasyMediawillconsiderably simplify the calibration task: it will automatically select the file names,and save the files at the right place.

Once the project is saved, the Statuswindow will be displayed as follows:


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You are now ready to use your new media in the Printmodule. To make sure thateverything is correct, open the Printmodule, select your media, select the correctresolution and printing mode, and open the dialog box that contains the ColorManagementoptions. It should look like this:

Advanced topics

Printer's state, and choosing the right parameters

Some parameters will slightly affect the print's quality. We will have a deeper look atthe settings usually available on different printers. However the availability of thesesettings may vary depending on the selected machine.

Visually check the printed patches. The measuring device will not detect most of theproblems caused by over-inking (bleeding, cockling, etc.), so if you see a problemwith the Pmaxdetected by EasyMedia, you will have to lower it.

Nozzle check: before every calibration you should check that every nozzle isfiring correctly. This function is available on most printers' panel.


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This test is read as follows: the lack of a horizontal line shows that thecorresponding nozzle is clogged. If the horizontal line is present, but misplaced, itshows that the shot is deflected. In either case, you should clean the heads.Sometimes successive cleanings do not eliminate the deflection; in that case,

continuing cleaning is worthless.

On this picture, we see that when a nozzle does not fire straight, we have awhite line near a darker line. If you are unable to correct the problem, we advise

using the lowest possible head height in order to minimize the deflection, withinthe media acceptance.

Resolution: Choosing the right resolution is done according to differentparameters:

Production speed Ink amount to match good densities. Even more on fixed dot printers, low

resolution will usually put less ink and may give insufficient densities. If the

dark inks target, or the linearization target, seems too light, we advise testingwith the equivalent target that includes mixed-ink patches. Not taking inaccount saturated patches, if the density is too low, it is a good idea toperform the test with a higher resolution.

Output precision: it is worthless to print at 1440 dpi if it is a banner that willbe viewed from a couple of metres away, contrary to an A4 photo.

Some media need to be printed at a higher resolution in order to lay downthe ink more slowly (transparent films). This parameter is often linked to asmaller dot size.

When 720 dpi is often considered as the standard resolution, printermanufacturers often give the optimal resolutions (e.g. 540x1080 dpi for theMimaki JV5).

For some printers (Canon IPF, HP Z series ), available resolutions depend onthe selected media type (media parameter in the software linked tohardware adjustments). Caldera chose to abstract these resolutions withgeneric names (Canon: Draft, Normal, High). This is why it is notrecommended to change the media type during the calibration. For instance,Canon's Plain Paper is limited to 1200 dpi for the High resolution,whereas it is 2400x1200 dpi for the Glossy Paper. So if you switch the


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media type during the calibration, what is already done won't have ameaning anymore.

For contone modes (Canon RGB, HP Z CMYK), the RIP resolution may bedifferent from the output resolution (Canon RGB : 600 dpi contone2400x1200 halftone).

Number of inks:Using light inks allows to reduce graininess for low densities.Another benefit is lowering the micro-banding by improving ink coverage.

Without light inks

With light inks

However you should be careful about some limitations when using light inks:

It is worthless to use light inks in highest densities. You should stop thembefore.

Using too much light inks for middle-high and high densities may lead toinsufficient densities, resulting in problems in gradients.

Using too few light inks will increase the grain, especially for lowest densities. More scarcely, too much light ink may cause ink drying issues for middle

densities.

A profile without light inks may often be more neutral than with light inks. Also light inks are more likely to be subject to metamerism, so ink shifts are

more likely to appear when using them.

So you will have to find a balance in light inks usage.

With some texture media (textiles, canvas), the interest of using light inks islimited, since the dots are less visible than the texture of the media, as youcan see in this example:


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Without light inks

With light inks

On the other hand, more and more printers are equipped with additional inkslike orange-green (hexachrome) or red-green-blue. Those inks allow a gamutincrease and a grain reduction. Management of those inks in Caldera Softwarevaries:

Canon IPF: you can choose between halftone CMYK and CMYKcm, whichdon't use them and are calibrated the standard way, and contone RGB,which uses embedded profiles from the Canon SDK, but withoutEasyMediacalibration for the moment.

2009 Epson printers: orange and green will be implemented. HP Z series: other than classical halftone CMYK and CMYKcmk, a contone

CMYK mode is available and can be profiled under EasyMedia.

Using photo or matte black: Matte black is used to obtain higher densities onmatte media. It is not recommended to use it on glossy, backlit and film media:resulting densities and scratch resistance are too low, because pigments do notpenetrate the media.

Overprint: In order to obtain suitable densities on some media (textiles), someprinters allow you to put more ink in the same place. Be careful when using thisoption because using it on medias that do not need it will lead to a worse controlof densities and increased grain.

Pass number: In the same way it is recommended to paint a wall in successive,thinner layers, rather than a unique layer, the more passes you select, the moreink you will be allowed to put on the media, because the ink will dry better. Onthe other hand, a higher pass number will lower the print process, so choosing itis a compromise between speed and quality. Also banding is less visible with ahigher pass number. This parameter is often linked to the selected resolution.


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Weaving: more and more printers, like Epsons, offer a weaving control in orderto decrease the perception of borders between passes. It is also possible to selecta waved border rather than the usual straight border. However, the results mayvary, and some high densities may let the waves appear. This parameter also

affects the print speed. Uni or bidirectional printing: Bidirectional printing will usually be faster than

unidirectional printing, but may also affect quality:Bidirectional alignment: you should be careful about this because a wrongalignment will let the offset between left-to-right and right-to-left firing appear.This also depends on the media thickness and head height. A wrong alignmentwill increase the grain:

Good alignment

Wrong alignment

Ink drying: since print speed is increased in bidirectional printing, drying timebetween passes will be lower. Therefore you will usually be able to put less inkthan with unidirectional printing. This is more visible with eco-solvent printers.Some other artifacts may appear, like the infamous football field, consisting inalternate darker and lighter bands because of insufficient drying between passes.


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Head height: According to media thickness or undulation, you will have to adjustthe head height in order to avoid scratches during the print. However, the moredistance between the media and the head there is, the more droplets deflectionyou will get, therefore increasing the grain.

Lowest position

Middle position

Highest position

Media thickness:Some printers provide a compensation for media thickness inaddition to the head height. Because of this parameter, it is worth helping the

correction of firing position, especially for bidirectional printing.

Heaters: On solvent printers, an important task will be adjusting the heaters.Such a printer is usually equipped with 2 to 4 heaters, which can beindependently adjusted. Usually, if the media heating is insufficient, inkacceptance will be lower. On the other hand, when there is too much heat, themedia may be undulating and may be scratched by the head. Also, for sometextiles, too much heat may prevent the ink from penetrating well enough beforethe evaporation of most of the solvent. There are two approaches here:

Convex:the heater placed immediately after the head is set higher than theothers, opening the pores of the media wider in order to allow ink penetration.

Concave:the same heater is set lower than the one just before the head inorder to make a thermal shock which will open the pore.

Some very thick media will need the highest possible value. On the other hand,papers do not usually accept much heat. Usually the heat needs are linked tomedia thickness and nature because the heat needs to pass through the media.

The media must have a good contact with the printers platten in order to getgood thermal transmission (no waves).


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Also manufacturers often give good start values, which are usually configured bydefault in Caldera Software.

Feed adjustment: Because of winder tensions, media weight and mediaadhesion, the media advance between passes may be inexact. So this can lead tosome banding effects:

Positive banding:white lines appear between passes because the advance istoo important. The feed adjustment must be decreased.

Negative banding: on the opposite, when the advance is too small, passoverlapping will occur. In this case, you need to increase the feed adjustment.

Delay between passes: Some printers provide such a parameter in order toimprove ink drying. Because some high ink densities needs medias that have avery low ink acceptance, this option may save the day. However, be careful,because this parameter lowers the print speed.

Head scan amplitude: In order to improve speed on narrow prints, some printersallow a selection of the head scan width: job, media, or full width of the printer.However, the ink acceptance may be reduced if the head only scans the width ofthe job, because the drying time between passes is reduced.

If you use a small width roll every time, select the media width rather thanthe printer's width to increase speed.

With wider rolls, it is recommended to scan media-width or printer-width,even for narrow jobs, to avoid drying issues.

EasyMedia also provides the Horizontal tiling option, whose effect is torepeat the print along the media width if the printer does not provide optionsto force a full width scan.

Winder:Some printers are equipped with a winder able to operate with tension.Even if this is usually not necessary for steep media, it might be useful for flexiblemedia or media that tend to stick to the printer's platten.

Some printers like Mutohs Spitfire provide a pre-print tensor. Make sure that it is

activated.


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Dot distribution:With variable dot printers, dot gain ratio and dot distribution areusually measured and optimized during the driver's development at Caldera's,because EasyMedia does not provide the corresponding measure tools for themoment. However some drivers allow the user to change the dot ratio in order to

optimize graininess in light tones, but forcing too much small and medium dotsmay lead to a lack of density for some intermediate values, which will be visiblein gradients. So usage of this function is a balance between graininess anddensity.

Normal curve Lack of density

Also, a wrong dot distribution may result in having micro-banding by lack of inkcoverage.

Ink transitions

Analysing the dark inks target allows to correct some print parameters: A doubling of vertical lines and a visible grain result from a wrong

bidirectional alignment.

A doubling of horizontal lines is the consequence of a bad feed adjustment.On printers like the Mutoh Spitfire, it may also result from a deactivated pre-

print tensor.

Pass overlapping or white lines between passes indicate a wrong feedadjustment.

A fuzzy placement of droplets indicates a too high head position. Also if itvaries slightly by waves along the media width, it indicates that the mediaundulates too much because it is too hot or the vacuum is not too weak.

EasyMediaproposes the light inks target first. However, these adjustments mustbe carried printing the dark inks target, even more if this one includes composite

patches.


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Comparing light and dark inks curves:

Light inks over darks Dark inks over lights

Both curve screens allow you to define limits of evaluation range for each target.Values found by EasyMediado not usually need any adjustment. However, whensome saturation remains undetected you will have to interfere.

If the limits are after the first saturation point, put them just before it. If light inks curves have higher densities than dark inks curves, please check

that you have measured both targets in the right order, first light, then dark.

If light and dark curves overlap, it means they are the same, so we adviseyou to make sure:

that you have actually printed a light inks and a dark inks target, and nottwice the same target.

that you have actually measured the right target for each. You may eliminate some high densities measure errors by lowering the limit,

even if there is no saturation.

Dark/light ratio curves:


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Curves are relatively straight. A measure error will appear as a peak in these curves and may alter the

dark/light ratio evaluation. If this peak is at one end, we advise restraining

the evaluation range. Unfortunately in the case below, we wont be able toput it away without losing most of the measure, so we will ignore this error.

Multiple peaks usually result from a wrong choice of measured targets.

Transition curves

We will notice that even if the curves are automatically adjusted in function ofprevious evaluation, you will often have to fine-tune them again to compensatesome problems that cannot be measured.

The maximal obtained density for light inks should not exceed the Pmax valuegiven for the measured corresponding curve, in order to avoid saturation issues.

The same way, the Pmax value given for dark inks measure indicates a first-shotevaluation of where to stop light inks.


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Generally, the light inks stop will be defined in function of maximal density foreach ink. So it is possible to come back and fine-tune transition curves according

to linearization limits, then redo the linearization process with the correctedtransitions.

Too much light ink can cause too low an ink limit in linearization or total inkevaluation, so you will have to lower the quantities of light inks.

If lowering the curve does not help, you can also force a stronger replacement oflight inks for high densities when selecting Numbers.

When you lower the quantity of light inks for light tones, the graininess willincrease. So you will have to find a balance between saturation risk and

graininess.

Using light inks to render high densities increases the global ink consumption, sothe cost of the print.

When using too much light ink rather than dark inks for high densities, this maylead to a lack of density, which will be visible in gradients.

Using light inks for high densities will usually lower the total ink limit. Too much light ink can cause saturations for middle tones that tend to disappear

for higher densities because there is too much liquid.

Total ink limiting

The limit given at the linearization time for each ink will be applied whenprinting the ink limit targets.

If you force a value in the InkClipping, Each Inkfield, the minimum of thisvalue and the value from the linearization will be taken.

If you already have an estimation of the ink limit, we advise entering thisvalue as well as a slight margin in the InkClipping, Globalfield. So the mix of


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inks will be nearer the final values. Because of the dark/light transitions,starting with a too high value will result in a different mix, which usuallygives an improper apparently lower limit.

Above 200 %, if you think there is no visual difference between values after agiven value (every patch from the column is black and looks like the oneon the next column), even if there is no saturation, it is worthless to set ahigher limit than . Actually it would only increase the ink consumption.

It is the right moment to find out the optimal values for the passes number (ifnot linked to the profiling configuration) and heaters by successive prints. Incase of saturation, trying to raise up the heaters is a good start.

Diffuse, dripping and wet patches are actually too inked. Negative banding in high densities only results from too much ink. A matte effect on a glossy paper results from either the use of the wrong

black (matte black on Epson or Canon printers), or ink saturation.

If the borders of patches tend to be over-inked, this is a result of ink fleeing tothe edges. It is a typical case of saturation on solvent printers.

A strange grain having no link to the screening is the consequence of inkpacking together.

A whole wet horizontal band may be the consequence of one of theseproblems:


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The dominant ink does not blend well with the others. You will have tolimit the use of this ink.

There is too much light ink in the mix. In this case, you will have to fine-tune the dark/light transitions and redo the linearization, then print a newink limit target.

A horizontal band which seems saturated in lowest shown densities, thengood and then satu

Documents

Easy Media profiling guide