Addresses of the Durst Distributors

EUROPE

ANDORRA Tf : 21366 FOTO CI E COLOR Avda. eri txe l l , 66 ANDORRA LA VELLA

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AMERICA

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VENEZUELA TONALITE SA Apartado 3240 CA-RACAS 1010A

Tf: 218089

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ALGIERS Tf : 650768 Soc iete Nationale Les Nouvelles Galeries A lgeriennes Direct ion Importation Departement Photo 67 , rue Larbi Tebess i BELCOURT CANARY ISLANDS Tf : 247684-87 MAYA P.O. Box 757 Calle Villalba Hervas 5 SANTA CRUZ DE TENE-RIFE EGYPT Tf: 902671 /869237 SOB HY ZA'KY 147 (A) Ramsis Street CP,JRO NIGERIA. Tf : (01) 862597 BOLA OGUNS PHOTOGRAPHIC EQUIPMENTS LIMITED 98, Cemetery Street P.M .B. 1069 EBUTE - METTA LAGOS Nigeria SOUTH AFRICA Tf : 28-3020 FRANK & HIRSCH PTY. LTD. P.O. Box 1803 JOHANNESBURG 2000

ASIA

ABOU DHABI Tf: 44643 SALAM STUDIO & STORES P.O. Box 417 ABU DHABI HONG KONG Tf : 5-540111 JEBSEN & CO. LTD. (AGFA GEVAERT Dept.) P.O. Box (Aberdeen) 4539 Scomber Building, 11th Floor No. 1, Yip Fat Street Wonq Chuk Hang HONG KONG INDONESIA Tf: 593401-5 PT. INTER-DELTA Post bag 3019/ JKT JI. Let. Jen. S. Parman 78 (SliDi) JAKARTA JAPAN Tf: (3) 580-2051/9 ASAHI OPTICAL CO. Ltd. Prof. & Ind. Prod. Sales Dept. G .P.O. 895 TOKYO 100-91

KOREA Tf : 65-4741-6 DOOSAN INDUSTRIAL CO., LTD. P.O. Box Kwangwhamoon 280 108-4, Susong-Dong Chongro-ku SEOUL

PHILIPPINES Tf: 406541 COLUMBIA TRADING COMPANY PHOTO SUPPLY 716, R. Hidalgo Street QUIAPO, MANILA

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AUSTRALIA

AUSTRALIA Tf: 9380400 HANIMEX Pty., Ltd. 108 Old Pittwater Road BROOKVALE (Sydney) N.S.W. 2100

NEW ZEALAND Tf: 448-146 HANIMEX (NZ) LTD. P.O. Box 40-041 Poland Rd. Glenfield AUCKLAND 10

Congratulations on your Durst AC 650. You now own a colour enlarger with automatic filter and exposure control, manufactured to Durst's strict quality standards.

This is a quality product by Durst of Bolzano, Italy, a firm that has for over 40 years specialised in designing and making enlargers for every field of photography. We are confident that this colour enlarger will give you supreme results . With its convenient handling and perfect operation it will serve you well in all printing jobs with positive or reversal colour papers or in black-and-white.

This instruction manual will. explain to you in detail your enlarger, its assembly, operation and advantages. To get the most out of the Durst AC 650, please take the trouble to read these instructions thoroughly before you start working with the enlarger. It will be well worth your while. The more familiar you are with the operations and controls, the better you avoid annoying failures or even damage.

If after reading this manual you are still ·uncertain on any point, the Durst agency in your country will always be happy to help you. Or write directly to us.

We wish you much fun and success with your Durst AC 650.

Durst AG, Bolzano, Italy

Contents

1.0.0 Components and controls

2.0.0 General note

3.0.0 Technical data

4.0.0 Assembling the enlarger

4.1 .0 Assembling the baseboard 4.2.0 Fitting the colour head 4.3.0 Inserting the negative carrier 4.4.0 Fitting the metering frame 4.5.0 Fitting the lens 4.6.0 Checking and changing the tungsten-halogen lamp 4.7.0 Connecting the transformer 4.8.0 Conversion to 6 X 6 cm

5.0.0 The enlarger in practice

5.1 .0 General points 5.1.1 The panel light 5.1.2 Selecting the mixing box 5.1.3 Inserting film strips and single negatives 5.1.4 Setting the magnification 5.1 .5 Focusing

5.2.0 Enlarging colour negatives 5.2.1 Entering the reference value 5.2.2 Basic calibration 5.2.3 The first test enlargement 5.2.4 Density and filter correction (calibration)

5.3.0 Enlarging colour transparencies 5.3.1 Density and colour correction (calibration) for slides

5.4.0 Enlarging black-and-white negatives 5.4.1 Correcting converging verticals

5.5.0 The slope control 5.5.1 Explanation of the slope control 5.5.2 Checking the slope setting

6.0.0 Copying

7.0.0 Maintenance

8.0.0 Trouble shooting table

6

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'-----3

--. 1

1.0.0 CompcnE:nts and controls

1) Baseboard 2) Screw bolts 3) Backing plate 4) Column base 5) Enlarger column ), 6) Linear magnification scale for 50 mm lens 7) Linear magnification scale for 80 mm lens 8) Reference value scale for 50 mm lens 9) Reference value scale for 80 mm lens

10) Carr iage 11) Vertical adjustment crank 12) Colour head 13) Push-in metering frame 14) Lens panel 15) Lens (extra) 16) Lens standard 17) Milled screw to secure lens panel on standard 18) Knob to secure colour mixing head on carriage 19) Focusing knob 20) Tightening screw for friction drive 21) Red filter 22) Negative carrier 23) Format mask pair 24) Mask retaining strips 25) Stop pins . 26) Key to close negative carrier 27) Cow . . er 28) Fixe l filtration key for transparency enlargements 29) Black-and-white key 30) Panel light key 31) Focusing light key 32) Slope control 33) Density control knob 34) Blue/yellow colour control knob 35) Green/ magenta colour control knob 36) Red/cyan colour control knob 37) Adjustable scale dials 38) Mixing box selector lever 39) Lamphouse 40) Lamphouse cover 41) Lamphouse cover latch 42) Tungsten-halogen lamp 43) Reflector rim 44) Porcelain lamp fitting 45) Cable from colour mixin.g head

46) Transformer 47) Exposure button on transformer

2.0.0 General note

The Durst AC650 enlarger has 8 Jtomatic density and colour control. It uses a fully electronic colour head which automatically measures and controls the exposure time during the exposure itself.

The automatic system enlarges colour negatives without the need for manual measurements by a colour analyser. Hence the AC 650 combines the functions of a colour enlarger and of a colour analyser, density meter and exposure timer. These units are thus unnecessary and not even usable with the AC 650.

For black-and-white enlargements the automatic system again controls the amount of light. Automatic control can be switched off for enlarging colour transparencies.

The Durst AC 650 takes miniature films (24X36 mm) and roll films up to 6 X 6 cm (2'14 X 2'14 inches) . The standard enlarger is supplied complete for enlarging miniature films and includes the transformer, tungsten-halogen lamp, negative carrier and lens panel for the 50 mm lens. Only the -'ens itself is not supplied. For enlarging 6X6 cm and 4.~, :X 6 cm (2'14X2'14 and 13/4X2'/2 inch) films a conversion kit 1!f3 available separately (Order code : COSIXKIT 66).

3.0.0 Technical data

Type

Film size

Light source

Filter colours Metering cells Exposure control Operating range

Fully electronic enlarger with automatic colour and exposure control 24X36 mm 6 X 6 cm (2'/4 X 2'14 inches) with conversion kit 12 volt 100 watt tungsten-halogen lamp Blue, green, red Silicon photodiodes Additive, automatic 0.5 to 100 seconds in each colour

17

Magnifications with 50 mm lens with 80 mm lens Baseboarc1 size Maximum height with fully raised enlarger head

3 to 14 X linear 1 to 8 X linear 50X55 cm (19.7X21 .7 inches)

104 cm (40.9 inches)

4.0.0 Assembling the enlarger

4.1.0 Assembling the baseboard

Push the screw bolts (2) through the backing plate.(3) and baseboard (1) and screw the bolts into the appropriate threaded holes in the column base (4). A hexagonal spanner to fit the bolts is enclosed.

4.2.0 Fitting the colour head

Mount the colour head (12) on the carriag.e (10) and secure with the knob (18). The detent of the colour head must engage the groove in the shaft of the carriage (10).

4.3.0 Inserting the negative carrier

Push the negative carrier (22) fully into the colour head (12). The carrier is already fitted with glassless format masks for 24X36 mm films.

4.4.0 Fitting the metering frame

Push the metering frame (13) into the unit underneath the negative carrier. The frame must be firmly engaged in the colour head to ensure correct electric contact. Use the metering frame supplied with the enlarger for 24X36 mm films; alternatively use the COSIXCEL 66 frame of the conversion kit for 6X6 cm films.

4.5.0 Fitting the lens

Screw the 50 mm lens (15) (not supplied) into the recessed lens panel (14). Then insert the panel with the lens into the lens standard (16) so that the aperture scale face·s forward. Tighten the milled screw (17) to secure the lens (15) in its panel (14) on the lens standard (16) . For 6X6 cm films screw the 80 mm lens (not supplied) into the flat panel and fit it on the Durst AC 650 in the same way as the 50 mm lens.

Note: Neither the Durst AC 650 enlarger nor the 6 X 6 cm conversion kit includes a lens. Do not use a Wide-angle enlarging lens.

For enlarging 24 X 36 mm films use only five- or six-element enlarging lenses of 50 mm focal length and aperture' f/2.8.

For example: Durst Rodenstock Schneider

50 mm NEONON tl2.8 50 mm RODAGON f/2.8 50 mm COMPONON-S f/2.8

Similarly, when enlarging 6X6 cm films use only five- or six-element enlarging lenses of 80 mm focal length, for instance: Durst Rodenstock Schneider

80 mm NEONON 80 mm RODAGON 80 mm COMPONON

The lenses listed all have an M39 screw thread. If you have a lens meeting the above requirements but with an M25 thread, mount the lens in the panel with the FLARING adapter ring , available as a separate accessory.

7

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8

4.6.0 Checking and changing the tungsten-halogen lamp The tungsten-halogen lamp (42) is factory-mounted in the lamphouse (39). To be on the safe side, however, check the correct fitting of the lamp (42) in case it has become loose during shipping.

To do this, turn the latch (41) , remove the lamphouse cover (40) and check that the pins of the tungsten-halogen lamp (42) are fully pushed into the white porcelain fitting (44). Check also that the tungsten-halogen lamp (42) is firmly located in the lamp holder.

To change the tungsten-halogen lamp (42), remove it from the lamp holder and unplug the white porcelain fitting (44). Push the pins of the new lamp into the fitting (44) and push the whole lamp into the lamp holder - while pulling aside the retaining springs - so that the lug at the reflector rim (43) engages the corresponding notch in the lamp holder. Then close the lamp house cover (40) again.

Take special care never to touch the inside of the tungsten­halogen lamp reflector. Use only Durst tungsten-halogen lamps (Order Code: COLAMP 100 S) in your Durst AC 650, for these lamps are specially selected for consistent colour balance and light output.

4.7.0 Connecting the transformer After assembling the enlarger, connect the transformer (46) to feed the colour head: Plug the cable (45) from the colour head into the socket on the transformer. Plug the transformer mains lead directly into a mains supply socket. The transformer has a 1.5 amp fuse.

4.8.0 Conversion to 6 X 6 cm For enlarging 6 X 6 cm (2'/4 X 2'/4 inch) films a conversion kit (Order code: COSIXKIT 66) is available separately.

It consists of the following items: - Lens panel for 80 mm lenses (SIRIOPLA) - 6X6 cm metering frame (COSIXCEL 66) - Pair of 6 X 6cm format masks (SIVOPAR 66) - Anti-Newton glass (SIVOGLA AN)

When converting to the 6 X 6 cm film size note the following points:

(1) Use an 80 mm lens (see also section 4.5.0) and fit this on the lens standard with the flat SIRIOPLA lens panel.

(2) Insert the COSIXCEL 66 metering frame. (3) Push the mixing box selector (38) to the rear to the

.marking 66; this ensures even illumination of the 6X6 cm negative area.

(4) Replace the 24 X 36 mm format masks in the negative carrier by the SIVOPAR 66 masks ·for 6X6 cm. To remove the miniature format masks push the masks themselves towards the retaining strips (24) to disengage them at the other end of the frame. Then insert the mask marked SIXMA in the lower section and the mask marked SIVOMA in the upper part of the negative carrier. For optimum film flatness replace the SIVOMA mask in the top section of the carrier by the SIVOGLA AN anti-Newton 9lasl1. For enlarging 4.5 X 6 cm (13/4 X 2'/2 inch) films inse(;t a pair of SIVOPAR 45 masks (available separately) in the

. negative carrier.

5.0.0 The enlarger in practice

5.1.0 General pOints

5.1.1 The panel light The panel with the scales is illuminated to facilitate reading of the filter and 9.ensity settings. When not required, switch off this panel light with the key (30).

3031

38 22-___ 26

----22

:.--- -==- 25

23

Zl

19

11

"--- 5

--- 7

5.1.2 Selecting the mixing box The sliding mixing box selector (3S) permits optimum adjustment of the light concentration for 6 X 6 cm or 24 x 36 mm films:

Pull forward for 24 X 36 mm f ilms Push backwards for 6 X 6 cm (21 /2 X 21 14 inch) films

5.1.3 Inserting fi lm strips and singlenegatives The f i lm to be enlarged - which must be free from dust - is placed in the negative carrier (22). To insert film strips push up the upper carrier section; it locks in its open position.

Press the key (31) to switch on the focusing light. Now insert the strip of film from the front so that no white light emerges past the edge of the image - for that could lead to erroneous readings. Press the key (26) to close the negative carrier.

Two pins (2S) in the negative carrier facilitate centering of film strips. For 24 X 36 mm films push the pins to the front stop and for the 6 X 6 cm film fo rmat to the rear stop. To insert single negatives remove the negative carrier (22) from the colour head. Place the negative accurately over the format mask (23) opening, close the negative carrier to lock the film in pos ition and push it into the colour head.

With the COSIXKIT 66 conversion kit the .ourst AC 6S0 can also be used for enlarg ing 4.SX6 cm films. A su itab le pair of format masks is available separately (Order code : SIVOPAR 4S) .

5.1.4 Setting the magnification d!f~ To obtain the required magnification raise~.:Jwer the colour head with the crank (11) . The actual magnification is shown on the scales (6) or (7):

Scale (6) : ~i agnifications with SO mm lens Scale (7) : Magn ifications with SO mm lens Adjust your masking frame or paper holder on the baseboard to obtain the image area you want on the print.

5.1.5 Fosucing Focus the projected image by raising or lowering the lens plane with the friction drive controlled by the knob (19) . Switch on the focusing light with the key (31) and switch off any room lighti ng. Open the lens to its maximum aperture. ' Focus on the plane of the printing paper, in other words on the base of the masking frame when you use such a frame.

5.2.0 Enlarging colour negatives When en larging colour negatives the AC 6S0 automatically carries out all necessary colour and density measurements duri ng the actual exposure cycle . Metering cells in the metering frame record the required amounts of blue, green and red light.

5.2.1 Entering the reference value As the metering cells are in the enlarging head, they do not automatically take into account the magnification - Le. the distance between the lens and baseboard. To allow for this, read off the appropriate reference value on the enlarger column (S) and enter it in the digital counter (27) 'on the automatic colour head. To do this, press the appropriate small keys marked w ith + and - above and underneath the counter (27) . Pressing a plus key increases the number, pressing a minus key reduces the number.

Obtain the reference value from the left-hand scale on the column (SO mm/S.6) when enlarging with the so mm lens at f/ S.6. Use the right-hand scale (SO mm/ S) when using an SO mm lens at f/s.

As a rule we recommend that you make all enlargements at these lens apertures. At small magnifications (below S X linear (6) with the SO mm lens and below 3 X linear (7) with the SO mm lens) you can however stop down the lens by one

9

stop and double the reference value. If you make enlargements at the next larger lens aperture, halve the reference value used .

5.2.2 Basic calibration The enlarger is precalibrated at our factory - which largely saves you the trouble of making filter tests. This basic calibration applies to Kodacolor II film and Kodak Ektacolor or Agfa colour paper. If you enlarge with other types of colour negative or on colour papers of other makes, the exposures are likely to need a different light composition. Hence the enlarger needs recalibration. In any case, the basic calibration sets up the unit only for average values of current colour negatives and papers.

If however you use Kodak or Agfa colour paper and Kodacolor II film and allow for the appropriate paper emulsion (speed variations in different packages of the same brand) you sh.ould obtain acceptable results. A calibration chart is enclosed with the enlarger, indicating the Kodak filter correction values or the Agfa filter combination specified for the colour paper used in the cal ibration.

Compare the Kodak filter corrections (or Agfa filter combination) on your paper packet with those on the calibration chart. Then adjust the automatic colour head by the difference between these filter correction values.

Example: KODAK EKTACOLOR 78RC (or 74RC) PAPER

Yellow Magenta Cyan . .,- -

Correction values on calibration chart + 15 + 15 -

Less: Correction values of your Kodak paper, e.g . -10 - 5 -

Difference (Kodak values) + 25 + 20 -

Converted to scale values (Kodak values divided by 15) + 1.7 +1.3 -

10

The difference in exposure factors between your paper and the paper used in the basic calibration is allowed for as follows:

Your exposure factor Ratio (a)

Calibration exposure factor

ej . 90180 = 1.1

The logarithm of this ratio, multiplied by 10, gives the scale value to which you set the density control knob :

Scale value on density Ratio control knob

(10 x log a)

0.5 -3.0 0.6 -2.2 0.7 -1 .5 0.8 -1.0 0.9 -0.5 1 0

+ 0.5* \

1.1 1.2 + 0.8 1.3 + 1.2 1.4 + 1.5 1.5 + 1.8 1.6 . + 2.1 1.7 + 2.3 1.8 + 2.6 1.9 + 2.8 2 + 3.0

• In our exampl e thi s would therefore be + 0.5

The zero setting of the filter control knobs and of the density control knob are the calibration settings for the enlarging paper used in our factory calibration . (But please see calibration shee!.)

The difference values obtained indicate the difference between our calibration paper and your paper. Hence you only have to enter in the automatic colour head the calculated scale values : Adjust plus values by turning the control clockwise and minus values by turning it anticlockwise. and minus values by turning it antlclockwise. If at any later time you switch to a new pack of Kodak paper,

34 32

recalculate the filter and density differences in the same way as described above. For Kodak Ektacolor paper set the slope control (32) to 70 %. (see section 5.5.0 for an explanation of the slope control).

Example: AGPA COLOUR PAPER TYPE 5

Yellow Magenta Cyan

Filter combination on calibration sheet 70 40 -Less:

Basic filter combination for your Agfa paper 100 20 -

Difference -30 + 20 -

Converted to scale values (Agfa values divided by 20) -1.5Y + 1.0M OC

. Set the automatic colour head to these scale values in the same way as in the previous example,.

Keep the density control at zero; in this case you obtain the correct setting by a test exposure as Agfadoes not indicate exposure factors on the paper packages (see section 5.2.4.) . For Agfa paper set the slope control (32) to 30% (see section 5.5.0 for an explanation on the slope control).

If at any time you switch to a new pack of Agfa paper, recalculate filter and density differences in the same way as described above.

5.2.3 The first test enlargement Always make the first test enlargement with a negative

,* of average density (neither too heavy nor too weak masking; 'it should have been normally exposed);

* of balanced colour distribution (a multicoloured subject against neutral. background, for instance a street scene) ;

* that was not taken by brilliant sunlight or at dusk.

Make the first test enlargement at a medium magnification, for instance on 18 X 24 cm or 8 X 10 inch paper.

To make the first test enlargement : * switch off the room light and enlarger light, * place the paper in the masking frame, * press the exposure button (47) on the transformer.

The exposure takes place in three stages: blue exposure, g"reen exposure and red exposure. The enlarger automatically switches to green and then to red once the photocells have" recorded the correct amount of light of the colour in question. This automatically compensates also for voltage fluctuations.

Pro,cess, rinse and dry the exposed print according to the instructions of the processing kit. An ideal complement to this enlarger is our compact automatic RC 20 processor.

Once "the test enlargement is dry, assess it by daylight or a daylight-matching light source. If the result meets your taste for density and colour, the enlarger is correctly calibrated and you can go on to enlarge further negatives. If the magnification remains the same, you only have to insert the paper and press the exposure button.

5.2.4 Density and filter corrections (calibration) * Density ,correction: If the result obtained with the first test enlargement is not correct, first check the density - i.e. see whether both highlights and shadows show sufficient detail. If the image is to be denser (darker) you need more exposure, so turn the' density control knob (33) clockwise.

If tk ".-int is already too dense (too dark), correct by turning the density knob anticlockwise.

Each unit on the density control knob scale corresponds to 1/3 lens stop. Hence three divisions are exactly one lens stop and adjusting the density control by 3 units is equivalenf _ to doubling or halving the exposure time.

* Filter correction : Once the density is correct, check the colour in the test enlargement. If the print is for instance too yellow (yellow cast) simply turn the appropriateJ ilter control knob (34) towards blue - i.e. anticlockwise.

11

28 32

27

Starting point

12

Similarly, correct as follows for different colour casts :

Colour cast Correction when enlarging colour negatives

Yellow Turn filter control knob (34) towards blue (anticlockwise)

Blue Turn filter control knob (34) towards yellow (clockwise)

Magenta Turn filter control knob (35) towards green (anticlockwise)

Green Turn fi iter control knob (35) towards magenta (clockwise)

Cyan Turn filter control knob (36) towards red (anticlockwise)

Red Turn filter control knob (36) towards cyan (clockwise)

Each unit on the filter control knob scales is equivalent to 10 densitometric filter units, or 15 CC units or 20 Agfa filter units.

* Density correction after appreciable filter correction: Every filter control knob correction not only modifies the colour balance but also increases or decreases the .exposure by comparison with the test enlargement. Turning either the density control knob (33) or the filter control knobs (34, 35, 36) clockwise increases the exposure, yielding a: denser print; turning the cOl1.trols anticlockwise makes the result lighter. As you assess the colour balance in an enlargement that is already correct in density, you will not want to change the density in the course of a colour correction . . The following table shows the density correction required .in the opposite direction to any given filter correction to keep the resulting print density constant

Yellow/ blue Magenta/green Cyan/ red

Filter · Densi ty Filter Density Filter Density corr. eorr . eorr. eorr. eorr. eorr.

Scale values Scale values Scale ·val ues

0.5 0.05 0.5 0.25 0.5 0.2 1.0 0.1 1.0 0.5 1.0 0.4 1.5 0.15 1.5 . 0.75 1.5 0.6 2.0 0.2 2.0 1.0 2.0 0.8 2.5 0.25 2.5 1.25 2.5 1.0 3.0 0.3 3.0 1.5 3.0 1".2 .•

If for instance the print has a magenta cast and you correct by 1 scale unit towards green (turning the filter control knob (35) anticlockwise by 1 unit), you have to compensate the density control by a 0.5 scale value (i.e. tu:rn clockwise by 0.5) . See bottom left illustration on page 12.

The requ ired density compensation is not the same for a given filter correction of yello~, magenta or cyan. This is because our eyes are not equally sensitive to. the three primary colours.

If however the setting of all three filter control knobs is adjusted by .1 unit clockwise and the density control at the same time by 1 unit ant i cloc~wise, the resulting print remains unchanged in density and colour balance.

Hence you can control density not only by the density control knob but also by simultaneous adjustment of all three filter controls up or down. This correction is available i'n addition to the density control, thus increasing the setting range. Once you have an enlargement of perfect density and colour from a test negative, you have arrived at ideal settings of the density -and fi lter control knobs for your conditions (paper, negative and processing).

Now move the zero position of the scale dials (37) to the zero posit ion of the control knobs. This fixes the calibration positions. From this calibration position you can make manual co rrect ions at any time you like.

5.3.0 Enlarging colour transparencies

To enlarge colour transparencies (slides) press the «Fix.F. »

(s lice) key (2a) . Th is disengages the automatic colour and .... density metering system ; the slide key is thus equivalent to

the so called fixed-filtration key in printers. Posit ive transparencies normally require enlarging light of a constant colour (and hence fixed filtration) from one original to the next. Transparencies also vary only little in density so that the automatic density measurement is also switched off.

Naturally you have to allow for changes in light intensi ty , reaching the baseboard at different magnifications, which is done by entering the appropriate reference value (a or 9) from the column in the counter (27) on the colour head (see section 5.2.1) , Even with the metering switched off, voltage fluctuations do not affect the result.

33 34 35 36

Set the slope control (32) to 30 '%. (See section 5.5.0 for an explanation of the slope controL)

For the first test enlargement keep the filter control knobs and the density contro l knob at zero. The zero notches of the filter control knobs should in this case be iii the top (12 o'clock) position. When enlarging mounted slides, . use the SIDIA slide mask available separately. I

Select an average multicoloured slide of low brightness range (bright/dark contrast). Enlarge this to a medium print size (1a x 24 cm or a X 10 inches) . When you make the f irst test enlargement you will notice that reversal paper basically goes black on processing. The greater the exposure of the reversal paper, the lighter the print becomes. _

5.3.1 Density and coiour correction (calibration) 'for slides * Density correction: Check f irst whether the print appears correct in density. Unlike an enlargement from a negative, too dark a print needs more exposure - you have to turn the density confrol knob clockwise to correct. If the print is too light, the exposure was too long ; in this case correct by turning the density control knob anticlockwise. Again each scale unit of the density control knob is equivalent to 1/3 stop and 3 units are equivalent to 1 lens stop. Correcting the control by 3 units is thus equivalent to doubling or halving the exposure time.

* Colour control: If the test enlargement is correct in density - i.e. with visible detail in the darkest shadows and lightest highli~, s - check .the colour balance. If for instance the test enlargement is too yellow, turn the appropriate filter control knob towards . yellow (clockwise). This 'is opposite to the correction in enlargmg negatives .

Here then is a summary of corrections for various colour casts :

Colour cast Correction wheh enlarg ing colour slides

Yellow Turn filter control knob (34) towards yellow (clockwise)

Blue Turn f ilter control knob (3~) towards blue (anticlockwise)

Magenta Turn filter control knob (35) towards magenta (clockwise)

Green Turn filter control knob (35) towards green (anticlockwise)

Cyan Turn filter control knob (36) towards cyan (clockwise)

Red Turn fi lter control knob (36) towards red (antJClockwise)

Each scale unit of-the filter control knobs is equivalent to 10 densitometric fi lter un its or 15 CC units or 20 Agfa filter units.

* Density correction after appreciable filter correction: In addition to altering the colour balance, any filter control knob correction also affects the exposure, yield-ing a denser or a lighter print. To keep print density constant when the filter control knobs are used for correct ion, the density control knob must be turned in the opposite sense to compensate, as ind icated in the table in section 5.2.4.

Once you have an enlargement of -correct density and colour from the test transparency, you can enlarge all further' transparencies with the same settings of the densitYilnd colour , control knobs. -

If you are using Cibachrome A paper and change the paper package, correct the filter setting for the new paper emulsion.

13

For example Yellow

Basic filter values of old paper pack 40

Less: Basic filter values of new paper pack 25

Difference (CC values) +15

Scale value difference (CC values divided by 15) + 1

+ correction clockwise correction anticlockwise

Magenta

00

00

00

0

5.4.0 Enlarging black-and-white negatives

Cyan

10

25

-15

-1

For enlarging black-and-wh ite negatives press the B & W key (29). This disengages the blue, green and red exposures; pressing the exposure button then results in only one exposure by white light. With the B & W key depressed, the metering cells remain operative and during the actual exposure measure the required amount of light for the negative being enlarged. You establish the correct exposure time - i.e. the correct setting of the density control knob (33) - for your enlarging paper by an initial test exposure.

To do th1s select a negative of average density (neither overexposed nor underexposed) and moderate contrast. Set the enlarger for a medium magnification (18X 24 cm or 8 x 10 inch print) and enter the reference value from the enlarger column in the colour head counter (see section 5.2.1).

Set the density and filter control knobs to zero (notches vertically on top) and turn the slope control (32) to 20 '% (see section 5.5.0 for an explanation of the slope control). Make several part exposures on a sheet of enlarging paper, for instance with the deniil ity control knob (33) set to -2, -1,0, +1 and +2. The processed test enlargement then immediately shows which

29 32

14

density setting was correct. Turning the control knob clockwise increases the exposure time, i.e. yields a denser (darker) print and vice versa .. Each unit on the density control knob scale is equivalent to 1/3lens stop. Hence 3 scale units are exactly equivalent to 1 lens stop, halving or doubling the exposure time.

In addition to density control with the density control knob you can als'o regulate the density (exposure time) with the cyan filter control knob (36). The direction and degree of correction is the same as with the density control knob. This greatly extends the adjustment range.

With the red filter (21) in the light path you can observe the image while the enlarger light is switched on and the black-and-white enlarging paper in position on the baseboard (for example to adjust the degree of cropping) .

5.4.1 Correcting converging verticals Converging verticals in an image are caused by tilting the camera during the exposure. If for instance you photograph a high building against the sky from street level, the verticals in the negative converge upwards. This unwanted effect can be corrected by tilting the colour head, the lens standard (16) and the masking frame or paper holder.

To tilt the colour head, slack off the knob (18) . To tilt and laterally adjust the lens standard (16) slack off the locking knob behind it. The degree of tilt can be noted on scales on the lens standard and of the colour head; that way you can always reset the enlarger to previously used values. To keep the image sharp over the whole print with the enlarger head tilted, stop down the lens by one or two stops (and double or quadruple the reference value for the exposure control) to increase depth of focus. The degree of distortion control is limited by the depth of focus of the lens and by the exposure variation across the image being corrected .

With the colour head tilted, part of the enlarging paper receives a greater projected light intensity (and hence effective exposure) than the rest. This can be compensated by shading that section during the exposure.

Note: Correction of converging verticals is possible only in black-and-white enlarging, for the additive exposure sequence makes shading impossible during colour enlarging.

5.5.0 The slope control

Adjust the slope control (32) as indicated in the appropriate section for:

- Enlarg ing colour negatives - to 70 % with Kodak papers

- to 30 % with Agfa papers

- Enlarging colour transparenc ies - to 30 %

- Enlarging black-and-wh ite negatives - to 20 %

These values were checked at the factory and should not require further mod ification . When you enlarge colour negatives on papers of other makes, use fi rst the Kodak values and 'make a test enlargement as described in section 5.2;3 to a medium magn ification , to check density and colour correction .

5.5.1 Explanation of the slope control The purpose of the slope control is to compensate reciprocity failure effects.

The effective light sensit ivity of photographic materials decreases with increasing exposure time. The speed loss varies with different papers.

This characteristic is corrected with the slope control. The slope control produces a certain percentage increase of the exposure time for the blue, green and red exposures. The higher the selected percentage value, the more the exposure is increased.

The sensit ivity of the three print layers (blue-, green-, red-sensitive) does not drop evenly with increasing exposure t ime (see graph). As the slope control provides only one reciprocity correction in terms of dens ity (namely fo r the green exposure) appreciable magnification variations can also affect the colour balance of the print. Filter values should therefore always be calibrated at a med ium magnification .

5.5.2 Checking the slope setting Once you have establ ished the correct settings for the density and filter controls at a medium magnification, make an

.. :;

Green (density)

] 40'+-----,---- , --,--,--,--++--r->''-------->' Theoretical

~ u o ~20't---~--~-r-~~+-~¥----u ~

~ g' 10t----t-- - +--tif--7''t--:l'-- - _i___-=-d xposure time 'i 8 +---+-- - --j Increase by o s lope contro l i 6t----t---f~~~+-+---_i___-~ ., ~ 4+---+-~7L~___ir-+-+---+_-~ .., ., u ., ~ 2'+--~~--+_---i-+-+---+--~ u

2 6 8 10 20 40 Uncorrected time

enlargement at the smallest and at the highest magnification. If both these yield prints of the same density (not colour balance) as your medium" enlargement, the slope setting is correct. If there is a noticeable difference, ~et the enlarger again to the min imum magnification and correct the print density with the density contro"1 knob (33) until it matches the density of the medium-size print. Then set the enlarger to maximum magnification and make a slope test series with constant settings of the density and filter control knobs : For instance make test exposures with slope settings of 30, 45, 60 and 75 %. The slope setting that yields a print of . correct density, matching enlargements at the smallest and medium magnificat ions, is the correct slope setting for your paper.

Although the densities match, colour enlargements at the maximum and minimum magnifications will show different colour balance. This colour variation is riot however noticeable in the normal magnification range (i.e. print sizes between 9 X 13 and 24 X 30 cm or 3'hx 5 and 10X 12 inches).

For this reason always calibrate the enlarger (sections 5.2.4 and 5.3.1) at a medium magnification.

If however you frequently make big enlargements of 30 X 40 cm or 12 x 16 inches, it is worth establ ishing a special calibrat ion for these.

The same applies to colour negatives - even of the same make - that greatly deviate from the density of the negative used for calib ration . For appreciably denser or more strongly masked negatives can also lead to exposure times at -which the sensitised layers of the paper no longer re'act in the same way as under the calibration conditions. Th is would then again cause a colour sh ift in the print.

6.0.0 Copying

The Durst AC 650 can be used with the copying film holder (Order Code: SIRIOREP) and a suitable copying lighting unit (Durst COPYLAM 2 or 4) for copying on sheet film.

For this purpose insert the copying film holder ·in the enlarger in place of the negative carrier and set up the copying lighting unit against the baseboard. Adjust the field to be covered on the baseboard and focus

15

with the vertical adjustment crank (11) and the focusing knob (19) while the focusing light is switched on, i.e. the key (31) depressed. After selecting the field of view, focus to get the format frame lines of the ground glass screen sharply projected onto the orig i'nal being copied. For further details refer to the operating manual for the Durst SIRIOREP copying film holder.

The Durst AC 650 can also be used as a copying stand for the camera. The latter is mounted on the column with a camera adapter (Order Code: SIRIOCAM) available separately.

7·.0.0 Maintenance

(1) Focusing: The focusing adjustment uses a friction drive. After considerable use this may become too loose. In that case tighten the screw (20) underneath the knob (11) with a screwdriver.

(2) Rack rod: Periodically grease the rack rod of the column with vaseline or acid-free grease.

(3) Lens: Period ically clean the lens with a fluffless cloth .

(4) Durst cover: When not in use, cover the enlarger with a dust cover (Order Code : SIRIOCUF) or keep it in a cupboard.

Important: (a) Before opening the colour mixing head, or (b) when changing the tungsten-halogen lamp, check always that the transformer plug Is disconnected from the mains supply.

16

8.0.0 Trouble shooting table

Problem Possible causes

Tungsten-halogen lamp fails to light (a) No cu rrent (press the Fix. F.

or 8 & W key afresh) (b) Poor lamp contact (4.6.0) (c) Faulty lamp (4.6.0) (d) Fuse blown on transformer

Print underexposed (a) Wrong mixing box sett ing (5.1.2)

(b) Reference value not entered (5.2.1)

(c) Incorrect slope sett ing (5.5.0) (d) Wrong lens aperture (5.2.1) (e) Wrong calibration setting on

density contro l knob (5.2.4 c r 5.3.1)

(f) Incorrect calibration of colour head (5.2.2)

(g) Colour correction also requ ires compensating density correction (5.2.4)

(h) En l3rg ing paper exposed t;lrough back

Print overexposed (a) Photocell in metering frame dirty

(b) Wrong metering frame used (4.4.0)

(c) WronQ, mixing box setting (5.1.2)

(d) Wrong or no reference value entered (5.2.1)

(e) Wrong slope value setting (5.5.0)

Print unsharp (a) Friction drive of focusing has become loose (7.0.0)

(b) Colour head moved up or down without refocusing

Image laterally reversed (a) Negative or slide inserted with

emulsion s ide up (b) Paper exposed t~rough back

·Print fogged (a) Darkroom safelight too bright (b) Light leakage into enlarging

paper box . (c) Stale enlarging paper (d) Enlarging paper stored too

warm

Colour variations (a) Incorrectly calibrated enlarger (5.2.0 to 5.2.4)

(b) Anomalous colour distribution (predominant colour) in negative or slide

(c) Use of different film or paper types (5.2.2)

(d) Extreme magnification (5.5.2) (e) ExceptiOnally dense negative

(5.5.2)

Density variations (a) Incorrect slope set~ing (5.5.2) (b) Greatly underexposed or

overexposed negative or slide (5.5.2)

17