Cibachrome (the Silver Dye Bleach Process)

Research for this Webpage is still in progress, courtesy of Michael Talbert


  1. Early History; Gasparcolor (early 1930s to 1950s)
    Processing Gasparcolor DP
  2. Ilford Colour Prints (Ilford Colour Print Material; 1953)
    From 1963
  3. The Cilchrome Process (1964)
    How Silver Dye Bleach Materials work
    Image Sharpness and Dye Stability in Silver Dye Bleach Materials
  4. The P-7A Process (mid-1960s)
    From 1969
  5. Cibachrome Transparent CCT-D 661 (1969)
    Cibachrome P-10 Process for Cibachrome Print CCP-D 182 and Cibachrome Transparent CCT-D 661 (1973)
    Cibachrome P-18 Process for Cibachrome Print CCP-D 182 (1974)
6. Cibachrome-A and Process P-12 (1974)
   Cibachrome-A processing kits (1975 US; 1976 UK)
   Cibachrome-A print material CCP-A 182E
   Printing filters
   P-12 process for Cibachrome-A material

Introduction
Cibachrome
Print materials, and the later Ilford Ilfochrome print materials, were designed for making prints directly from colour transparencies.

Unlike conventional colour negative/positive printing papers, where the coloured dyes making up the picture were generated by colour couplers in a “colour developer”, Cibachrome print materials were manufactured with the dyes already incorporated in the printing paper.

Cibachrome materials, or papers, were multi-layer products, each layer containing a dye of the opposite colour to the layer’s sensitivity.

The top layer was sensitive to blue light and contained a yellow dye.
The next layer was a non-sensitized yellow filter to prevent any blue light affecting the middle and bottom layers.
The middle layer was sensitized to green light and contained a magenta dye.
The bottom layer was sensitized to red light and contained a cyan dye.

One problem for any Silver Dye Bleach materials was their extreme insensitivity to light. This is because each layer has effectively a complimentary colour filter coated on top of the sensitive emulsion of that layer. For example, the top layer, sensitive to blue light, has a yellow dye placed over the blue sensitive emulsion, the opposite colour of blue.

The later Cibachrome print materials were manufactured with an extra emulsion layer coated adjacent to each of the dye containing layers. These extra layers contained no dye, but were in contact with the dye containing layers and served to increase the speed of the print paper.

Early History; Gasparcolor
The idea of producing a colour print by bleaching coloured dyes is not new. As long ago as 1906, Dr.J.H. Smith of Zurich manufactured a printing paper containing three coloured dyes viz: red, yellow and blue, with the purpose of bleaching the dyes in the paper by the action of light to make colour prints from Autochrome transparencies. The process was not a success, but another way was found by forming a silver halide image in the paper by making it light sensitive, developing the image in a black and white developer, and then, by using chemical means, bleaching out only the dyes corresponding to the negative image formed by the developer. Then, removing all the silver halides from the paper by silver bleaching and fixing to leave only the dyes, in the same way as negative/positive colour printing papers, such as Agfacolor and Ektacolor.

The first person to achieve any success with the Silver Dye Bleach process was the Hungarian chemist, Dr. Bela Gaspar. Based on the work of another researcher, Carl Schinzel, Dr. Gaspar invented a colour transparency material for use with motion picture animated advertising films in the early 1930s. The films were made using a very complicated method, by making three exposures of each frame through tri-colour filters on black and white motion picture film. This produced a separate negative record of the red, green, and blue components of the picture. Because Dr. Gasper’s material was a positive to positive printing material, each frame had to be printed again onto the black and white motion picture positive film to produce a transparency of each of the red, green, and blue records. Finally the black and white transparencies were printed through their corresponding tri-colour filters, a red record black and white transparency was printed through a tri-colour red filter (and so on) onto Dr. Gaspar’s colour Dye Bleach material to produce a colour motion picture film.

If Gaspar’s material had been made in large sheet film sizes, it could have been used to make duplicate transparencies, possibly from Autochrome, Dufaycolor, or other additive “reseau” transparencies. (Kodachrome 35mm film was first marketed in 1936). This was never done, but by 1945 a printing material known as “Gaspar Opaque”, similar to a reversal colour printing paper, was being made and sold in America for photographers to make their own colour prints from transparencies.

Another material, maybe an improved version, appeared in 1953. This later material was known as “Gasparcolor DP” (Direct Positive). It was obtainable in the USA, was similar to Cibachrome, and processed in much the same way. It was balanced for enlarger lamps (3200°K), and had to be handled in total darkness or under a safelight suitable for panchromatic black and white films (Wratten Series 3, or 5, or Ilford GB 908). It was said that with a brightness level of 10 foot candles, prints from “average” transparencies could be made with exposure times of 30 to 60 seconds. There was even a recommended filter pack for trial exposures given with each batch of Gasparcolor DP, possibly similar to the “Grundzahl” figures stamped on each packet or box of Agfacolor paper.

Processing Gasparcolor DP
Five solutions were necessary to process Gasparcolor DP. The Developer, Dye Bleach, and Silver Bleach were supplied by the manufacturers, but the printer had to provide his own fixing baths. Any standard black and white general purpose fixing bath could be used. Four fixers for black and white films and papers at that time were:
Kodak Acid Fixing Salt with Hardener (UK)
Kodak Photo Fix or Kodak Acid Fixer (USA)
Ilford IF 2 Acid Fixing Salts (UK)

A stop-bath in step 2 was optional. If used, 30ccs of glacial acetic acid in 1 litre of water would have been a suitable formula.

A dozen sheets of 8 inch x 10 inch Gasparcolor DP could be processed in 2 US gallons of Developer or Dye Bleach. 2 US gallons of Silver Bleach served to process twice this amount of print material.
The processing was generally carried out in dishes.

Bath

Time
(Mins)

Temprature °F
Total darkness, or Safelight suitable for handling black and white panchromatic films
1. Developer

7

70
2. Stop Bath or Water Rinse

30 seconds

60 - 70
3. Fixer

5

60 - 70
4. Wash

8

60 - 70
5. Dye Bleach 

12

70
6. Wash

5 (max)

60 - 70
7. Silver Bleach

5

65 - 70
8. Wash

5 (max)

60 - 70
9. Fixer

5

60 - 70
10. Wash

10- 15

60 - 70
10. Dry

Notes:

  1. It was likely that the temperature of the Developer and Dye Bleach had to be kept within the limits of 69 – 71°F to achieve consistent results.
  2. Continuous agitation was recommended in the Developer and Dye Bleach and occasional agitation in the Silver Bleach and Fixing Baths.
  3. The negative images were made slightly light sensitive again in the Dye Bleach. It is possible that processing could be carried out in white light after step 3, but as the Dye Bleach in step 5 converts the images to a light sensitive form, steps 4 to 8 were best done in subdued lighting, or under a safelight filter suitable for black and white printing papers.
  4. It was important not to extend the wash times in steps 6 and 8.
  5. Rubber gloves were recommended for handling the prints in the Dye Bleach and Silver Bleach. Both solutions were strongly acid and corrosive to most metals.
     

Ilford Colour Prints (Ilford Colour Print Material)
In 1953, Ilford Ltd began a service for making postcard size (3½ inch x 5½ inch) prints from 35mm size amateur colour transparencies of any make.

In the early 1950s, no printing or processing machines were obtainable or sold in the UK for mass production printing of transparencies onto a print material. Ilford designed and made their own equipment, both printers and processors, for their colour print service. Instead of printing onto a multi-layer colour coupler type of paper, such as Anscocolor Printon, Ilford chose to employ a Silver Dye Bleach material. It was known as “Ilford Colour Print Material”.

Because of the extremely low light sensitivity of Silver Dye Bleach materials, the printing machines were equipped with 2¼ kilowatt Xenon arc lamps to make the printing exposures and thus achieve a reasonable print production rate of over 1,000 prints per hour.

The printing paper, or Silver Dye Bleach material, was allegedly made by Ilford Ltd, but was only for use in their laboratories for their print service. It was never sold on the open market, much in the same way as Eastman Kodak’s Kodacolor paper.

From 1963
Ilford’s colour print service lasted until 1963, by which time it became widely known that Ciba Photochemie in Switzerland was making a Silver Dye Bleach material by the name of “Cibachrome”. Ciba Photochemie had been interested in the Silver Dye Bleach process since the early 1950s and by 1963 had researched and developed “Cibachrome” for making colour prints directly from colour transparencies.

In 1963 Ciba AG, Switzerland, approached Ilford with a buy-out offer. The Ciba group comprised (i) Ciba AG, Ciba Photochemie AG (formerly Tellko AG, research laboratory near Fribourg) a manufacturer of sensitised photographic materials, (ii) Lumière SA France (near Lyons, acquired by Ciba in 1962) also a manufacturer of sensitised materials & of colour film (in the 1950s), and (iii) Gretag GmbH (Germany) a designer and constructor of equipment and instruments for use in the photographic industry.

There was no take-over by Ciba until 1969 but there began commercial co-operation between Ciba and Ilford to develop Ciba's dye-bleach print material for making prints directly from colour transparencies. Originally called Cilchrome ('Cil' derived from the names Ciba, Ilford and Lumière) the eventual product name reverted to Cibachrome (1969 in the UK).

A processing procedure for “Cilchrome” was published in the British Journal of Photography for 19th June 1964, by E.Ch. Gehret. It was also reproduced in the British Journal of Photography Annual for 1965 and some following annuals. The chemical formulae, given in the annuals, were worked out by E.Ch. Gehret. It is not an exact procedure, the material was still at the “research and development” stage at the time the processing procedure was published. It is based on some of the patents taken out by Ciba Photochemie.

Bath

Time
(Mins)

Temprature °C (maybe 24°C)
1. Black & White Developer

6

not stated
2. Stop Bath 3% Acetic Acid

not stated

not stated
3. “Standard Formal” Hardener. (Maybe 3% Chrome Alum solution, as in Ektachrome E2 and E3 processes). Optional

not stated

not stated
4. Acid Fixer

not stated

not stated
5. Dye Bleach First Stage

10

not stated
6. Wash

5

not stated
7. Dye Bleach Second Stage

not stated
8. Wash

not stated

not stated
9. Re-Halogenising Solution

10

24
10. Wash

not stated

not stated
11. Fixer

not stated

not stated
12. Wash

not stated

not stated
13. Dry

Notes:

  1. Only one temperature is given, 24°C, and this is for the “Rehalogenising" solution. It may, or it may not, apply to the other solutions.
  2. Some of the times for the steps in the procedure are not stated in the article.
     

The Cilchrome Process
Jack H. Coote described the working of the Cilchrome Print Process at a lecture at a meeting of “The Colour Group” of the Royal Photographic Society (RPS) on 16th October 1964. Part of the lecture is reproduced in “The Photographic Journal” for March 1965. He makes an interesting point about the printing exposures used for Cilchrome. The prints made at Ciba Photochemie in 1964 were exposed additively, one exposure through a red filter, one through green, and one through blue. Ciba claimed that this method produced a better separation between the three emulsion layers leading to a more accurate colour reproduction. Mr. Coote also mentions that another type of print material was in the development stage, specifically being designed for “white light” printing to give an equal quality in colour reproduction.

How Silver Dye Bleach Materials work
The material is made up of three light sensitive layers, one each sensitized to red (bottom layer), green (middle layer), and blue (top layer) light. Incorporated into each layer is a dye of the opposite colour to the layer’s sensitivity e.g. the middle layer contains a magenta dye, but the layer is sensitized to green light. The light sensitive layers with their dyes were coated onto a cellulose tri-acetate base. It was not possible to coat onto a paper base, owing to the high acidity and corrosive nature of the Dye Bleach bath.

The respective layer records the red, green and blue coloured image of the transparency, plus mixed colours, being recorded in two or, in the case of white, in all three layers.

After exposure, the material is developed in a black and white developer, fairly similar to one which might be used to develop black and white printing paper. This produces a negative silver image in each layer corresponding to a black and white negative of the red, green and blue components of the transparency.

For example, the image in the middle layer is a black and white negative of anything green in the transparency, or any colour which is partially green. A cyan colour, green/blue, would be recorded partly in the green layer and partly in the blue layer.

The next step is the Dye Bleach bath. The removes the coloured dye from the developed black and white negative image only, and leaves any dye not affected by the black and white developer. It works in the exposed parts of the red, green and blue images only. The remaining dye makes up the positive image to give a colour print of the transparency.

As the material still contains the unwanted exposed and unexposed silver halide, two more processing steps are necessary. In the next step i.e. the Silver Bleach step, the exposed metallic silver, formed by the black and white developer, has to be converted into silver halide which will be made soluble in the fixer.

The final chemical step is a Fixing Bath, which converts all the silver halides in the material, exposed and unexposed, to a soluble silver, which can then be washed out the print to leave only the dyes. The negative image is effectively “removed” from the Cilchrome (Cibachrome) print, the negative unwanted dye is bleached out in the Dye Bleach, and the exposed silver halide of the negative image is “removed” in the Silver Bleach and Fixer.

This is an outline of the earlier processing procedure. Later processes combined the Dye Bleach and Silver Bleach into one processing step. Earlier processes contained additional fixing baths as well as a separate Dye Bleach and Silver Bleach.

Image Sharpness and Dye Stability in Silver Dye Bleach Materials
The traditional method of generating coloured dyes to form an image in a colour film or a colour printing paper rely on a “colour developer” to react with “dye couplers” which are contained in each emulsion layer, producing a dye of the opposite colour to the sensitivity of that layer. For example, the red sensitive emulsion produces a cyan dye, whether it is a colour film or colour printing paper, the image is produced by means of a “colour developer”.

Unfortunately, there are very few colour developing agents that can be used successfully to produce coloured dye images. Also, the dyes which these colour developing agents produce have poor stability to light and are susceptible to heat, humidity, and chemical fumes, even in dark storage e.g. colour prints in an album.

Because Silver Dye Bleach materials do not have to generate a dye image by processing the material in a “colour developer”, there is far more choice of dyes which can be included in the three light sensitive emulsions. Cibachrome Print and Transparent materials contained dyes of the polyazo type, having excellent resistance to dye fading, humidity and chemical contamination.

Another advantage was a gain in print sharpness. There was a significant gain in sharpness in a Cibachrome print compared to a print made on conventional “colour development” paper such as the Kodak Ektachrome range papers. This gain in sharpness was due to minimal ”light scatter”, or irradiation, within each emulsion layer. In this context, “Irradiation” is light scatter within silver light sensitive emulsion layers. Light is scattered by reflection and spreads as it passes through overlapping silver grains in any light sensitive photographic material, film or paper. It causes unsharp images, as the light is spread out and definition suffers.

Each light sensitive layer in a Cibachrome material had a dye of the opposite colour to that layer’s sensitivity included in the layer. The coloured dye had a masking effect on any light scatter within the emulsion layer. For example, the magenta dye in the green sensitive layer ”neutralised” any scattered light in that layer by rendering it magenta, the opposite colour to green, and therefore the opposite colour to the layer’s sensitivity.

“Acutance dyes” were included in conventional colour materials, films and papers, to improve definition, but acutance dyes in Silver Dye Bleach materials are taken to an extreme level, hence greatly improving definition.

The P-7A Process
P-7A
, in the mid-1960s, was possibly the first Dye Bleach process to be used commercially. Silver Dye Bleach print materials and the chemicals for processing them were marketed first in Switzerland and later extended, under license, to laboratories in Germany.

From 1969
In the UK, by 1969, the material had reverted back to being called Cibachrome and a few professional laboratories had begun to offer a “hand print” service for making Cibachrome prints on photographic enlargers. The processing chemicals and the Cibachrome print materials were marketed by Ilford, and tank, drum, or machine processing was recommended.

Cibachrome could be dish processed, but at no more than one sheet at a time in a processing dish. The support base was fairly rigid, slightly thicker than the base of a resin coated colour printing paper, and did not bend easily. Because of the risk of the corners of one sheet damaging another, interleaving agitation of more than one sheet was not recommended.

Cibachrome Print material was to be handled in total darkness, or under a safelight fitted with a 15 watt bulb and a “Dark Brown” filter, such as Ilford 912. The near equivalent safelight filters which were suitable included Kodak Wratten 10H, and Agfa 166M, later known as “08”.

This Process P-7A processing sequence was in use for Cibachrome Print (CCP) in 1969.

Bath

Time
(Mins)

Temperature °F
Total darkness or recommended safelight filter (as above).
1. Developer

7

75 +/- ½
2. Stop Fix

3

73 - 77
3. Wash (Running Water)

3

72 - 78
4. Dye Bleach

7

75 +/- ½
5. Wash (Running Water)

2

72 - 78
6. Silver Bleach

8

73 - 77
7. Wash (Running Water)

2

72 - 78
8. Stop-Fix

4

73 - 77
9. Wash (Running Water)

10

73 - 77
10. Stabilizer

1

73 - 77
11. Dry; at temperatures up to 120°F

Total time: 47 minutes.

Notes:

  1. When processing in tanks, the use of nitrogen burst agitation in the developer and compressed air in the other solutions was advised. It was necessary to agitate very thoroughly in the developer and the two bleach solutions.
  2. Because of the corrosive nature of the two bleach solutions, the processing equipment used should be made out of inert plastic material. It was advised not to use stainless steel clips, tanks, or processing print baskets.
  3. The solutions were replenished at the rate of 6 fluid ounces per square foot of Cibachrome material processed, or 2 litres per square metre.
  4. As the Dye Bleach solution contained concentrated hydrochloric acid, adequate ventilation over the processing chemicals was important.
  5. It is not known if the Stop-Fix baths in step 2 and step 8 were identical.
  6. The yellow non-sensitized filter layer was bleached out in the Dye Bleach bath.
  7. The processing table gives no indication as to when “white light” can be used. It may have been after the second Stop-Fix bath.

Cibachrome Transparent CCT-D 661
In 1969, Ciba introduced a Transparent version of their Cibachrome Print material. This was equivalent to a duplicating film, such as Kodak Ektachrome Duplicating films, but with the added advantages of minimal dye fading and enhanced definition. It was available in sheet film and rolls, and was designed for making large, backlit, display transparencies.

Cibachrome P-10 Process for Cibachrome Print CCP-D 182 and Cibachrome Transparent CCT-D 661
By 1973 the then new Cibachrome P-10 process cut the total wet processing time to 36½ minutes, using four solutions and four washes.

Bath

Time
(Mins)

Temprature °F
Total darkness or recommended safelight filter (as above).
1. Developer DE

6

75
2. Wash

4

75
3. Dye Bleach FB

75 +/- ½
4. Wash

2

75
5. Silver Bleach BA

2

75
6. Wash

1

75
7. Fixer FX

8

75
8. Wash

6

75
9. Dry

Total time: 36½ minutes.

Notes:

  1. The temperature tolerance of the Dye Bleach, being the most critical solution, was ½°F either way from 75°F. The other solutions and washes could be varied from 73 to 77°F, the development temperature being the most critical.
  2. The working solutions were supplied to make 30 litres of solution, and replenishers were available to make 19 and 95 liters of solution.
  3. Rubber gloves, protective glasses and an apron were recommended, when mixing the Dye Bleach, because of the extreme acidity of the product!


A label from a box of Cibachrome Print dating from 1975 designed for Process P-10.
This was made in Switzerland and marketed in the U.K. by Ilford


The rear label of Cibachrome Print material CCP-D 182 showing a trial filtration of 10 Yellow and 30 Cyan, (10, –, 30). It is not clear what make of filters this suggestion refers to, but it could be either the Cibachrome A set of filters or, more likely, the Ilford Dilute Complimentary set of filters, as this label may pre-date appearance of the Cibachrome A filters.

Cibachrome P-18 Process for Cibachrome Print CCP-D 182
Three bath processing for Cibachrome Print CCP D-182 was introduced in 1974, by combining the Dye Bleach with the Silver Bleach. The temperature of the solutions and washes were raised to 86°F (30°C), the total processing time was reduced to around 17 minutes.

Because of the simultaneous action of the combined Dye Bleach and Silver Bleach, the working temperature of this solution was less critical. Plus or minus 2°F could be allowed for the Bleach Bath and Fixer.

The P-18 process was suitable for “one shot” processing in small cylindrical drums, such as the “Simmard”, “Kodak Printank”, the “Wilkinson” processor and others. Dish processing was not recommended, but could be employed for very large prints which might not fit into a drum. The processing times remained the same for drum, dish, or large continuous processing machines, such as the “Kreonite”, or “Colenta” machines.

Cibachrome Transparent CCT D-661 was not compatible with Process P-18, and laboratories printing on CCP D-182 and CCT D-661 either had to carry on processing both materials in the old P-10 process, or run two separate processes.

The three solutions were supplied in concentrated liquid form to make 25 litres of working solution, the Developer and Bleach as two parts each, A and B, and the Fixer as one part. According to W.D.G. Cox, writing in the British Journal of Photography Annual (BJPA) for 1977, it was possible to make up as little as 1 litre of Bleach or Developer working strength solution by taking 200 ml of part A and 100 ml of part B, and mixing these parts with 700 ml of water. He gave no indication of how to make a working solution of Fixer, but as the Fixer was supplied as a one solution concentrate, it might be assumed that 300 ml of Fixer concentrate was mixed with 700 ml water to make the working solution.

For large scale users, solution replenishers were available, again as concentrated liquids, to make 50 litres of each replenisher.

Bath

Time
(Mins)

Temprature °F
Total darkness or suitable safelight filter, Kodak 10H, Ilford GB908, or Agfa G4 (Dark green).
1. Preliminary Soak

1 - 4

83 - 90
2. Developer, DE-18

3

86
3. Wash

1

83 - 90
4. Bleach, BL-18

3

84 – 88
5. Wash

1

83 - 90
6. Fixer, FX-18

3

84 – 88
7. Wash

83 - 90
8. Dry

Total time: 16½ to 19½ minutes.

Notes:

  1. Minimum wash times in steps 3 and 5 were 45 seconds, but the times could be safely increased by 50%.
  2. Development continued in the washing step, step 3, therefore the wash times had to be kept constant for tests and final prints for each batch processed. The timing for the wash in step 5 was less critical.
  3. It was recommended to keep the development temperature between 85°F to 87°F (29.4 - 30.6°C) for consistent results.
  4. When processing in a drum, it may have been more convenient to remove the print from the drum after the Fixer step and wash the print in an open dish.
  5. The first step, preliminary soak, could be varied in time between 1 and 4 minutes according to the method of processing and type of processing equipment used.
  6. When dish processing, the room lights could be turned on nearing the end of the Fixer step.

Cibachrome-A and Process P-12
When the Cibachrome process was first introduced into the UK, the materials were designed to be printed and processed by professional colour laboratories catering for professional photographers who wanted to obtain the best possible quality prints from their transparencies, mainly taken on Ektachrome sheet film. However, in 1974, Ilford introduced a simplified version of the P-18 process (above), known as P-12, together with a colour print material intended mainly for printing and processing by the amateur photographer (hence Cibachrome-A).

In 1974 there were very few colour printing materials for making colour prints directly from colour transparencies. The best known material was Kodak’s Ektachrome RC paper, Type 1993. The paper was not readily available to the amateur photographer, nor were the Ektaprint R5 processing chemicals, (see Ektachrome paper section).

Although the minimum size of Ektachrome RC paper was 8 inches x 10 inches, and the packets of 25 sheets could be obtained by order through a photographic dealer, the minimum quantity of 5 gallons of each component of the Ektaprint R5 processing chemicals would have been likely to deter even the most enthusiastic amateur photographer from reversal colour printing.

Cibachrome-A processing kits
Following a successful field test in two cities in the state of Ohio in the USA in 1974, Ilford Cibachrome P-12 processing kits were made generally available in the USA in 1975.
The first kits consisted of:

20 sheets of Cibachrome-A print material, size 8 inch x 10 inch.
Enough chemicals to process the 20 sheets of Cibachrome-A.
A set of 18 colour printing filters, size 6 inches square, to alter the colour balance of the Cibachrome-A material, plus an Ultra Violet filter.
A print processing drum.
3 measuring cylinders.
A colour print manual.

These kits would have appealed to amateur photographers who had already done some negative-positive colour printing. They would already have owned some colour printing filters and maybe some of the other equipment. Cibachrome A material could equally well be processed in dishes, like black and white prints, although Ilford did not recommend this method of processing.

Cibachrome-A print material was available in various sizes up to 16 inch x 20 inch. An 11 inch x 14 inch size was sold in the USA and Canada. The almost equivalent size being sold in European countries was 16 inch x 12 inch. The 16 inch x 12 inch was a useful size as two 8 inch x 10 inch prints could be printed on one sheet.

To encourage amateur photographers to start making their own colour prints, especially those who were economically minded and objected to paying for a large size 8 inch x 10 inch kit, Ilford introduced “Cibachrome Discovery” kits in the USA in 1977. The kit was a smaller version of the 8 inch x 10 inch kit and contained 20 sheets of 4 inch x 5 inch Cibachrome-A print material plus a mini 4 inch x 5 inch processing drum. Also included were the set of printing filters, slightly smaller at 3 inches square, measuring cylinders and processing chemicals to process the 20 sheets of 4 x 5 inch paper.

Cibachrome-A kits were being sold in European countries by 1976. It seems the "Discovery" kits were sold in Europe (presumably including the UK) from 1978. They were known as “Cibachrome Mini Kits”, but included the same contents as the US "Discovery" kits.

Economically, the kits were an excellent “buy” for any amateur photographer who had no previous experience of colour printing, and was not keen to spend too much money in case they found colour printing too difficult and found more pleasure from making black and white prints.

The huge advantage of the Cibachrome-A process was that the complete beginner could make prints from colour transparencies and not colour negatives. The filtering, i.e. changing the colour balance of the print, was much more logical than printing from negatives. When printing from transparencies, a colour cast was always corrected with a filter of the opposite colour to the cast. There was the added advantage of using the transparency as a colour guide. If the transparency had a definite colour cast, something easily seen in a transparency but very difficult to detect in a colour reversed negative, a filter of the opposite colour to the cast could be added to the “filter pack” for a first test strip for an improved colour balance in the print.

Cibachrome-A print material CCP-A 182E
The light sensitive layers of Cibachrome-A were coated on one side of a white opaque plastic base. There was a gelatine layer coated on the back to prevent the material from curling emulsion inwards.

The material was designated “CCP-A 182E”. It was only available in a highly glazed surface, similar to Kodak's colour printing papers of surface F.

   

Above:
A packet of Cibachrome-A Print System material, CCP-A 182E, size 5 inches x 7 inches, with a “High Gloss” finish, much like Kodak’s 'F' surface for their colour printing papers.
This packet dates from 1976 and was intended for sale on the European market.

Right:
Rear label of the above packet, showing four “starting filtrations” for well known transparency films.
The emulsion Number of the material was 91A2 00-019.

Printing filters
Almost any set of colour printing filters designed for colour printing could be used to correct the colour balance of Cibachrome-A. Each kit of paper and chemicals contained a set of Cibachrome-A filters plus an Ultra Violet absorbing filter. The printing filters were graduated from 10 to 50 units in increments of 10 in yellow, magenta and cyan, plus a 5 density of each colour. A complete set contained 18 filters, plus the Ultra Violet filter. A heat absorbing filter was recommended, but heat absorbing glasses were normally fitted to most enlargers by the manufacturer. It is thought that the Cibachrome colour printing filters were similar in strength to Kodak colour printing filters CP-05 to CP-50.

To assist the printer in achieving the correct colour balance, basic filtrations for four types of reversal films were printed on the back of every packet or box of Cibachrome-A material. Generally the filtrations were made up of yellow plus cyan units, such as 60 – 40, (60 yellow, 0 magenta, 40 cyan), and it was recommended to expose a first test strip using one of the filtrations given, appropriate to the make of transparency being printed. The filtrations given were only a starting point, and it was extremely unlikely that a correctly balanced print would result from the first trial.

The filtrations printed on the packets could also be used to calculate the differences in colour balance between different batches of Cibachrome-A paper.

When filtering Cibachrome-A material, large changes in filtration were often necessary. Unless the print was extremely close to the correct balance, changes of less than 10 units of any colour would not be enough to make any significant difference to the colour balance. A strong cast could be corrected by a 40 unit Cibachrome filter (or equivalent Kodak colour printing filter).

P-12 process for Cibachrome-A material
Only three solutions were used to process Cibachrome-A. The process was based on the professional P-18 process with reduced times and fewer wash steps.

This process is for processing in the drums provided with the kits. There was a choice of three processing temperatures.

Load drum in total darkness.
Times are given in minutes under temperatures. It was recommended to drain the drum after each chemical step for at least 10 seconds.

Bath

(Temperature
68°F or 20°C)
Mins

(Temperature
75°F or 24°C)
Mins

(Temperature
82°F or 28°C)
Mins
1. Developer

2

2. Bleach

4

3. Fix

3

4. Wash

3

3

3
Dry

Total times: 13½, 12 and 10½ minutes (excluding drying time).

Notes:

  1. A safelight could be used, fitted with a filter suitable for black and white panchromatic films, such as a Kodak Series 3, Ilford GB 908 or Agfa G4. The safelight needed to be fitted with a 15 watt bulb and kept at least 30 inches (0.75m) away from the working surface. Safelight filters for colour negative printing papers were not recommended.
  2. Although this process was principally designed for processing in a drum, or Kodak “Printank”, the sequences could be used for dish processing. Processing times were the same and with dish processing it was particularly important to drain each test strip or print for at least 10 seconds before placing it in the next solution.
  3. Compared to colour negative-positive printing papers, the contrast of the material was high. Decreasing the development time by about half a minute was said to have been equal to a contrast drop of one black and white paper grade, i.e. from grade 2 (normal) to grade 1 (soft). It would work the other way, but it was very unlikely that any Cibachrome prints would have needed an increase in contrast.
  4. The wash time had to be increased when washing the prints in water that was much below 68°F. It was easier to wash the print in a dish than to attempt to carry out the wash with the print in the drum. Wet prints exhibited a slight red cast which disappeared on drying and it was recommended that prints were dried before assessing them for colour balance. Test strips and small prints could be dried in about 5 minutes by using an electric fan producing warm air or a domestic hair dryer.

This page last updated: 17th February 2017