4 0 J A N U A R Y / F E B R U A R Y 2 0 0 6

A Simple Way To Test ForFilm Speed

and Developing Timeby Steve Simmons

If you are going to be a black and whitephotographer,whether your final output is a traditionalblackand white print or a digital print, you need to testforyour personal Exposure Index and your personal de-veloping time. You cannot simply follow themanufacturer’sinstructions. Nor can you ask someoneelse or go online and ask in a discussion forum. There aresimply too many variables that are unique to each ofus.You need to do your own testing.

When I began my photo career — actually, it was ahobby back then — the zone system was explained pri-marily in Ansel Adams’ thin books of his first series, TheNegative. It was the type ofbook that made sense when Iread it.

It made sense, that is, untiItried to put what I thought Iunderstood into practice.Then I was lost. Then, inabout 1975, Fred Picker cameout withhis book, The ZoneVI Workshop. In this book, heexplained how to test, in apractical manner that I andmany others could actuallyunderstand and put intopractice. The name of thetesting procedure was “min-imum time for maximumblack.”

Here is how the procedureworks.

Finding the ProperProof Time

1. Take an unexposed neg-ative and process as you nor-mally do. Use the same de-veloper and fixing proce-dure. When this is processed,it will give you an almostclear piece of film. I say “al-most clear,” because whatyou now have is film baseplus fog. If you are using astaining developer, then youmay have a little stain aswell.

2. Now, set up your enlarg-

er to make an 8x10 print, and place your negative in thenegative carrier and up into the slot. If you are using alarge piece of film and making contact prints, then placeyour film onto the paper, and set your light source so thefilm is given good, even coverage.

3. Set your timer for a short amount of time, let’s say 5seconds. Find a piece of cardboard or some other opaqueobject. Another piece of enlarging paper maynot work,because there may be a small amount of light that getsthrough down to the easel.

4. Set the f-stop on your enlarging lens down 2-3 stopsfrom wide open.

5. Using the piece of opaquematerial, expose the paper in theeasel for several bursts of light.Move the opaque object across thepaper in increments, so that thepaper receives several five-secondexposures. As you move across, theexposures on the paper will buildup so that one section will havefive seconds, the next one willhave ten, then fifteen,etc., etc.

6. Then move the paper to yourtray of developer and process nor-mally. It is important that you useyour standard paper developer atits normal dilution for the normalamount of time. This has to bestandardized and done the sameway every time.

7. After the paper is developedand fixed, turn on the lights andlook over the successive stripsof darkening tones. At somepoint, you will not be able tosee the difference between twoadjacent strips. Write down thetimes for the two strips. For thesake of discussion, lets say youcannot see any difference be-tween 15 and 20 seconds.

8. This is too much time be-tween the strips, but you aremaking progress. Set the timerfor 3 seconds. Now repeat theprocess. Your strips now will be3 seconds, 6 seconds, 9 seconds,

5 seconds 10 seconds 15 seconds 20 seconds

Your first test for Minimum Time for Maximum Black maylook like this. This is a great place to start. For the secondeffort I would try increments of 3 seconds so that you mayget results like below. Below tells you your Minimum Timefor Maximum Black is 12 seconds. This now is your properproof time.

3 seconds 6 seconds 9 seconds 12 seconds 15 seconds

V I E W C A M E R A 4 1

12 seconds, and 15 seconds and if possible, 18 seconds.9. Process this paper again as usual.10. Now look at the paper and review the ever darken-

ing strips as you go across the paper. The 3 second stripshould be very light, 6 seconds a little darker, etc. Lookcarefully to see where the distinctions become invisible.For the sake of discussion, lets say the 12 and 15 secondstrips look the same. If so, then 12 seconds becomes yourproper proof time with this film, thispaper, this f-stopand this enlarger height. Record all of this information.

Finding Your Personal Exposure Index1. Load six holders with your film. Find an evenly lit

surface, such as a wall in the shade. Set your meter for themanufacturer’s recommended film speed. Take a meterreading of the light being reflected from the wall. Nowremember, your meter wants to make this, and every-thing else, a medium gray, which is zone 5. You are look-ing for a zone 1 density, which is the amount of densitythat will make zone 1 just perceptibly lighter than yourpaper’s maximum black. So, after taking this reading andgetting the possible f-stop and shutter speed combina-tions, close down 4 stops. Yes, closedown, as you wantthis tone to be darker than medium gray. So, if you aregiven a combination of 1/8 of a second at f11, for exam-ple, use 1/8 at f45. Now, pull the darkslide out only halfway. You want to expose only half of the film and leavethe other have unexposed. After partially exposing thissheet, do the samewith another sheet, but at a film speedof 75% of the recommended exposure index. Now, do athird sheet at a film speed of 50% of the manufacturer’srecommendation. Now, do a fourth sheet with a speedof125% of the manufacturer’s recommendation, andthen a fifth sheet with a speed of 150% of the manufac-turer’s recommendation. The sixth sheet can remain un-exposed.

2. Process these sheets as recommended by the manu-facturer or any guide book you may have. Use the devel-oper you want to use and the developing method youwill be using in the future. After the film is processed,look it over. You will see the five sheets with clear unex-posed areas, and slight density on the other half of thefilm. You should be able to tell which sheets receivedwhich exposures. You may have one or two sheets withlittle, if any, discernible exposure, and 3-4 sheets witheasily discernible and increasing densities.

3. Now, set up your enlarger as you did before. Use thesame enlarger height and f-stop. Use the same paper,contrast filter (if you used one before), and paper devel-oper. Place one of the negatives in the enlarger and ex-pose the paper for your proper proof time.

4. Process this test print as you normally do. You arelooking for the piece of film that creates a tone on thepaper just perceptibly lighter than that paper’s maximumblack. When you find it, you have discoveredyour per-sonal film speed for that film, that film developer, thatpaper, and that paper developer. What you are doing isbuilding the necessary density on the negative and theshape of its curve to adjust it to the shape of the curve forthe paper. You are now making the two fit together. Youcan check this necessary zone 1 density, but assumingyou are using a grade 2 paper or contrast filter, this densi-

ty is almost always between .09 and .14 above film baseplus fog. This is considered to be the target density forthis area of the negative.

It is important during these tests that you have a stan-dard print developer dilution and developing time. Donot vary either of these when doing this testing proce-dure.

Finding Your Normal Developing TimeThe next, and final step, is to find your “normal” de-

veloping time. In my case, I use zone 8 as the top of mynormal range. Many people use either zone 7 or 9. It doesnot matter, as long as you are consistent.

1. Find an evenly lit wall or flat surface. Here you wanta tone that is just barely perceptibly darker than the purewhite of your printing paper. Take a meterreading of thissurface. Again, remember, the meter wants to make ev-erything a medium gray, which is zone 5. You want thistone to be brighter than medium gray. If you are going touse zone 7 as the upper end of your normal scale, thenopen up two stops. That’s right, the exposure needs to beincreased. If you are going to use zone 8, then open upthree stops. Go ahead and expose the entire sheet. Infact, expose sixsheets.

2. Process these six sheets for different times. Do onefor the time suggested by the film and/or film developermanufacturer. Then do one for 60% of the recommend-ed time, one for 80%, one for 110%, one for 120%, andone for 130% of the recommended time.

3. When these sheets are processed you will see thateach one has a different density. Take one, perhaps theone developed for the recommended time, and place itin your enlarger. The enlarger should be set up exactly asit was for the earlier steps. Now cover up one half of theprinting paper with an opaque piece of cardboard.

Expose the other half of the paper through the testnegative for your proper proof time.

4. After processing this print, turn on your viewinglight and look at the two sides of the paper. If there is nodiscernible difference, then this sheet of film was pro-cessed too long. If the side exposed through the negativeis much more than barely perceptibly darker than theunexposed side, then it was not processed long enough.

You are looking for a tone that is just barely perceptiblydarker than pure paper white. If this test sheet does notshow any difference, then go to the sheet of film devel-

Here, within thelimits of theprinted page, isan example of apiece of printingpaper with azone 0 (clearfilm) and a zone1. The zone 1tone should justbe barelyperceptiblylighter than thezone 0 tonewhich was doneby the clear areaof the film

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oped for 80% of the recommend-ed time. Perform the same proof-ing procedure. Look at the re-sults. You are looking for a tonejust darker than the white of theunexposed paper.

What you are doing at this stepis building the top area of thefilm curve to fit onto your print-ing paper.

Once you find this sheet offilm, you have determine yourdeveloping time for putting thetop of your “normal” scale ontoyour printing paper. You willusually find that your develop-ing time is different than what isrecommended by the manufac-turer. That is fine. This is yourpersonal normal developingtime. From this point on, useyour personal exposure in-dex and developing timewith this film, film devel-oper, and printing papercombination for your “nor-mal” scenes. If you runacross a scene with more orless contrast, then you willhave to make adjustmentsto your exposure and de-veloping times.

You can also use thisproper proof time to checkall of your negatives in thefuture, as a test of how youare exposing and process-ing your film.

You now know how tocreate a full scale negativewith good detail and sepa-ration all up and down thescale.

At this point, you havethe basic knowledge andresults to go and make verygood black and white neg-atives. At some futurepoint, you may want to dosome more sophisticatedtesting with a densitome-ter. But for now, you are ingreat shape.

Scanning Your Nega-tives

I use the same exposureindex and developingtimes for all of my film. Itdoes not matter if I am go-ing to make a traditionalprint or scan my film for

some type of digital output.My goal in making a negative

is to make a good one that willserve me for either type of print-ing process. It is always impor-tant to get the right densities onthe negative that will allow formultiple interpretations. Gooddetail all the way up and downthe scale of the film is importantfor any type or style of output.

If you are going to be scanningyour film, I would still gothrough the exercise describedin this article. Now, there will beone more step.

Place the film in your scannerand begin building a scanningcurve that will bring the imageinto your computer as a full scalephotograph. Adjust the curve or

levels to bring in the imageas it proofed for you. Youmay want to make adjust-ments in the toe, midtones, or high values butyour scanning softwareshould allow you to do this.

You do not want to be inthe position of having tospend time correcting a badscan in your photo pro-gram. Too much manipu-lation of the curves, levels,contrast, brightness, etc.,will expose you to the riskof breaking up the smoothcurve of the histogram andposterizing the image. It ismuch better to create thescanning curve that willgive you an accurate andfull scale rendering of thenegative.

Once you build the curvefor the film and film devel-oper combination, save itand label it. Next time youwork with this film andfilm developer call up thescanning curve and use it.

Now you should be set.Enjoy.If you want to go on from

here and take a more scien-tific approach you can pro-ceed if you so desire. It canbecome an interestingstudy of sensitometry. Itmay or may not help yoube a better photographer.

Here, within the limits of the printed page, is anexample of a piece of printing paper with a pure paperwhite and a tone that is barely darker than pure paperwhite. For me, this would be zone 8. It can be zone 7 or9 if you prefer. I use zone 8 as the brightest tone in myprints where I want the hint of detail and texture. Forme zone 9 is pure paper white.

Chaco Canyon. 5x7 camera, 240mm lens, Tri-X developed in PMk.Here is an image that prints well on a #2 paper, with a #2 filter,and that scans as a full scale image into my computer for sometype of digital output. I have built a scanning input curve forthis film size, film type, and developer that I can load anytime Iam working with this combination. This reproduction was donefrom a straight scan of this negative.