| Early Agfa colour materials - researched by Michael Talbert |
|
Prior to the launch of the 'subtractive' Agfacolor Neu colour reversal (transparency) film (see following paragraphs), Agfa had marketed (since 1932) 'additive' colour film. This was similar to Dufaycolor film, producing a positive transparency. The film was processed in black and white reversal chemicals and had a 'reseau' type colour screen within its construction in order to provide the image colour when viewed by transmitted light. According to an Agfa price list of May 1934, it was available in roll film, flat film, and film packs. There were two types of Agfacolor additive 'reseau' films. One, Agfa Color film, dates from 1932, and the other, Agfacolor Ultra, a faster film, dates from 1934. Both these films were derived from Agfa Color glass plates, which were sold in Germany as long ago as 1916. Agfa did manufacture a 35mm film in 1933, but this was a Lenticular film, specifically for Leica cameras. The film had minute lenses incorporated into the film base, and transparencies were viewed with a Leitz projector fitted with a three band colour filter. The process was mainly used for cinematography and saw little use in still photography. It was similar to the earliest 'Kodacolor', a 16mm version for home movies made by Kodak in 1928. When “Agfacolor Neu” reversal film first made it’s appearance in 1936, it proved that a multi-layer colour film could be manufactured with the colour couplers incorporated into three separate emulsion layers coated onto a single 'support' and that this arrangement could be processed in a single colour developer. It was processed with a first developer and then the colour developer. It was available in Germany as 35mm 36 exposure film and by late in the 1930s it also became available in the U.K. The British Journal Almanac of 1938 gives a short review on Agfacolor Neu film and suggested it should best be exposed at 14 Scheiner in daylight (about 2ASA / ISO !), although Agfa quoted a speed of 17 Scheiner (4ASA). It cost 6 shillings (30p) for a cassette of 36 exposures including processing (1937 price). Processing was done by Agfa. In the 1930s Agfa had an address in Lawrence St, St. Giles High St, London, WC2, but its uncertain whether 'Neu' films were processed there. A multi-layer colour coupler type negative film (type B2 balanced for daylight and type G2 balanced for artificial light), was announced by Agfa (probably to the German film industry, U.F.A; for a Wikipedia definition: see below) in 1937. It was a 35mm film, designed for motion picture use, as the German Film industry already had much experience in, and the necessary equipment for, processing and printing large quantities of 35mm black and white film to a high standard. The first colour prints to be made from a multi-layer colour development negative film were printed onto an equivalent positive film, not paper. This positive (print) film was announced at the same time as the negative film stock. These negative & positive films were not manufactured in any quantity until 1939. The negative and positive films were certainly not on sale to the German public. At the beginning of WW.2, U.F.A. and other film studios in Germany were instructed by the German Propaganda Ministry, (Joseph Goebbels), to make several full length feature films using the new Agfacolor negative / positive films. At that time U.F.A. did not consider the new Agfacolor films were sufficiently technically advanced to do this, but they went ahead and made about 13 films, (some unfinished) during the war to 1945. Two types of negative film were available, Type B for daylight, type G for artificial light. The films were processed and printed using modified black and white equipment but owing to wartime conditions, some of the release prints were inferior. It was generally agreed that “Die Fledermous” showed the best colour quality. The processing procedure for Agfacolor negative film changed little over the next 30 years. After 1940, all research and development was done under the approval of the German Government. Some work was carried out on a special soft gradation reversal film for the production of duplicate negatives (negatives from negatives), but the film was only used for the duplication of short sections, spliced in with the original colour negative. In all cases, the original colour negative film which had been exposed in the camera and suitably edited, was used to make the release prints, and no duplicate negatives were ever made for the printing of a complete film. A number of the feature films made were never released to German audiences, either because the films were never completed by 1945, or were considered unsuitable for showing to the German public. The Agfacolor Motion Picture Negative films were panchromatic films coated with three emulsion layers, one sensitive to red light, one to green light, and one to blue light. Originally, when the negative films were first manufactured in 1939, the film speed was 10/10 degrees DIN, corresponding to about 6 ASA (ISO). A year later, one source claims this speed had increased to 16/10 degrees DIN, or roughly 25 ASA (ISO). As far as Michael has been able to find out, this claimed high speed applied to both types of film. However, another source states that, in 1945, the film speed was 14/10 degrees DIN, around 12 to 16 ASA (ISO). This is much more likely to be true, as this corresponds to the speed of the Agfacolor Negative films for still photography, CNT and CNK, introduced in 1949. The Agfacolor Motion Picture Negative films were similar in structure to the very early Kodacolor films, but Agfacolor film employed a different type of colour coupler. The Red sensitive emulsion layer was coated on top of the Nitrate base of the film. This layer contained the Cyan dye coupler which, on development, produced a negative cyan dye image in the exposed areas. A Green sensitive emulsion layer was coated on top of the red layer, incorporating a Magenta dye coupler, producing a negative magenta dye image on development. Because both the red and green emulsions were also sensitive to blue light, a yellow filter layer was coated on top of the green layer, preventing any blue light from reaching the bottom two emulsions. The final emulsion to be coated on the film was the Blue sensitive layer on top of the yellow filter. This contained a Yellow coupler, which on development, produced a negative yellow dye image. An anti-halation backing was applied to the base of the film containing a blue-green dye. The backing dissolved in the development step. The Nitrate film base, which was not “Safety Film”, was the same base as used for black and white motion picture films. The yellow filter layer consisted of colloidal silver in gelatin, which was removed from the film in the Bleach bath in the processing sequence. The red and green sensitive layers each consisted of a similar emulsion to the Agfa black and white film, Isopan F. The Isopan F film was a black and white panchromatic negative film with a speed of 40 ASA (ISO). The blue sensitive layer was a positive film emulsion, sensitized for blue light only, not panchromatic. No masking layers were incorporated in the negative films, nor did the colour couplers generate a coloured mask. No form of masking for contrast correction was ever used in the printing of the negative film. As far as Michael Talbert has been able to ascertain, the exposure latitude of the Agfacolor Negative Motion Picture film was about one stop, although this is very likely to mean one stop over-exposure. Over-exposed negatives would require increased printing time. Under exposed negatives caused thin shadows with no detail, low contrast, and poor blacks in the positive release prints. The Agfacolor Positive Film was a colour sensitive 35mm film used for making release prints from both types of Agfacolor Negative Motion Picture films. It was sensitized for 3,000°K tungsten lamps and had a slightly higher printing speed than the equivalent black and white positive printing material. On processing, it produced a colour transparency, but was not a reversal material, and the processing of it was similar to the Agfacolor negative film. It was not suitable for camera use. The structure of the film was similar to the Agfacolor negative film, having the same layer order. The bottom two layers were each made up of an ”Isopan F” film emulsion plus a Process film emulsion. (At that time, Process film was a slow speed blue sensitive film of fairly high contrast, mainly for use in Graphic Arts or for copying.) The top layer was a black and white Process film type of emulsion, sensitive to blue light, i.e. not panchromatic. More variation in manufacture was allowed for the Agfacolor positive film and batch variations of up to one stop in speed were permissible. The different colour characteristics of each batch could be filtered to a neutral balance when printing. All Agfacolor film, negative and positive, was manufactured at the Agfa Wolfen factory. Processing of the film was done in sprocket driven continuous machines, the film being processed at 9 to 15 feet a minute. Modified processing machines were used, originally intended for black and white films. They used stainless steel or glass tanks for the solutions. The processing room temperature was kept at around 20°C/68°F, as the processing solutions were used at 18°C/64°F. Approximate Processing Procedure for Agfacolor Motion Picture Negative Film.
As far as Michael Talbert has been able to ascertain, the processing of Agfacolor Positive Motion Picture Film was carried out in the same machines as for the Negative Film. The temperature for processing was 64°F/18°C. Two processing procedures were necessary, one for Motion Picture Film with no sound track and the other for Motion Picture Film with an optical sound track. Magnetic sound tracks were not invented until 1953.
Notes on both Motion Picture Positive Film processing procedures.
During 1944/45 Agfacolor Motion Picture film was being processed at the UFA laboratories at Kopenick, South Eastern Berlin. After 1945, it was included in the Soviet sector of East Berlin. Processing and printing was also carried out at the UFA studios at Neu Babelsberg, then the capital city of the German state of Brandenberg. Most of the feature films using Agfacolor materials during WWII were produced at the UFA Neu Babelsberg studios. Printing was done by tungsten illumination on De Brie printing machines which were, as far as Michael Talbert can ascertain, were originally used for black and white release prints. It seems the intensity of the printing light was altered by means of a paper ribbon over the light source in which round holes were punched at different apertures. It was also necessary to change the colour of the printing light to correct for:
AGFACOLOR Printing Filters for Colour Correction The printing filters used on the De Brie machines were made in the three subtractive colours, yellow, magenta, and blue-green. (Blue-green was later termed as Cyan. it was actually known as Blue-Green to begin with, possibly because it was translated from the German – Blaugrun). The purpose of the coloured filters was to change the colour of the printing light to correct for any tints or colour casts in the positive print, this being a transparent print on 35mm positive film. The filters were made in different depths or densities of colour. The highest density filter in each colour was numbered 100 strength, and the other filters were numbered in densities of 10, decreasing from 100, the lowest density being 10. Therefore a “set” of colour filters would consist of 10,20, 30, 40, etc Yellow in increasing strength up to 100, 10 Magenta in the same values, and 10 Blue-Green, in the same values. The whole set comprised of 30 filters. The value of the filters could be added together, 160 Magenta would be made up as, 100, 50 and 10. Obviously, when printing on a large scale, it was very important to keep records of the filtrations used when printing each batch of negative film. A simple system of designation was used to indicate the filter combination of any print. All filter combinations, using numbered values, were written in the order of Yellow, Magenta, Blue-green (Cyan). This sequence was chosen as it related to the same sequence as the order of the layers coated on Agfacolor negative film. A filter correction of a 70 strength Yellow filter and a 40 strength Magenta filter with no Blue-Green filters was written as 70 40 00. A filter correction of a 30 strength Magenta filter and a 60 strength Blue-Green filter and no Yellow filters was written 00 30 60. One filter could be used on it’s own, so e.g. a 50 strength Magenta filter would be written 00 50 00. There was no need for all three filters to be used as a correction because three filters superimposed on top of one another would make a neutral density or grey. In other words, if all three colour filters were of the same strength, they would cancel each other out and would not alter the colour of the print. A filter combination of 20 Yellow, 50 Magenta and 70 Blue-Green, would contain 20 “neutral density”. Therefore, if a value of 20 was subtracted from each filter the Yellow value would become 00 and this would cancel out the neutral density, or “grey” value, leaving a filter combination of 00 30 50. The colour correction filters were stapled over the paper ribbon aperture holes to adjust the colour balance and produce a neutral print. Residual colour casts in the printed, positive, film were removed by using a filter over the projection light source. In this case, the filter would be the same colour as the colour cast. If a print appeared too Yellow, or Magenta, or Blue-Green, it was corrected by placing a Yellow filter, or a Magenta filter, or a Blue-Green filter in the light source. A strong colour cast, one which could be seen very easily, was corrected by an equally strong filter value, such as an 80 filter. A very slight tint which might not be noticed was filtered out by a weak coloured filter, such as a 10 value. Red, Green and Blue casts were dealt with by combining Yellow plus Magenta to make a Red filter, Yellow and Blue-Green to make a Green filter and Magenta and Blue-Green to make a Blue filter. When printing the Colour Negative Motion Picture film onto the corresponding Positive film several test prints were made to find out the correct combination of printing filters which give the best colour rendering. Usually, “coarse” test prints were made with exposure variations and filter values of 30 units apart. A “coarse” test print would take into account any estimated casts of almost any colour. The strength of the filters used were from 30 to 90 in Yellow, Magenta, Blue-Green, Red, Green, and Blue; Red, Green and Blue being a combination of filters, as explained above. From this wide range of test printing a fairly good indication of the correct colour balance could be estimated. If the best colour in the “coarse“ test prints was estimated to be a print with the filters 00 60 60, (no Yellow filters, 60 Magenta filters, 60 Blue-Green filters), and this test print had a Magenta colour cast of, say, 20 units, another test print was exposed with the filter combination 00 80 60; i.e the Magenta value was increased to 80 to correct for the magenta colour cast in the 'coarse' print. Other test prints were also exposed at the same time varying the filtrations by say, 10 or 20 units around 00 80 60 (00 80 80, 00 80 70, 00 70 50, and so on). This series of test prints would “fine tune” the colour to hopefully arrive at an optimum colour balance and, with it, an optimum filtration value which could be used to make numerous release film prints. In the early years of World War II, much experimental work was done by Agfa on a process for making colour prints on paper. By 1942, Agfacolor Paper was available for making prints from Agfacolor negative motion picture film. It was originally decided by Agfa to release the negative/positive process to the general public as soon as World War II was over in Europe. But in 1945, production of film and paper had ceased at the Wolfen plant because of lack of basic raw materials and the collapse of Germany. Also, by then, the patents for the Agfacolor process became available to other photographic material manufacturers, such as Gevaert and Ferrania. Later on, both companies marketed colour negative/positive processes very similar to Agfacolor. The experimental paper, and some quantities of it, were originally made at Wolfen, but by 1949, both film and paper production had moved to Agfa’s Leverkusen plant, although Wolfen continued to make colour film, later known as Orwo. In January 1949, Agfacolor film was made available to the general public, and the first colour processing laboratories for processing and printing Agfacolor negative film were set up in Germany. As far as Michael Talbert is aware, Agfacolor negative film was first sold in the U.K. in July 1951. By June 1951, four processing laboratories had been established in the U.K. At that time, Kodacolor film was not sold in the U.K; the only Kodak film obtainable to the amateur photographer was the transparency slide and movie film called Kodachrome. Ektachrome film was accessible to the professional photographer in limited quantities. Colour prints could be made by the “assembly” processes, such as Kodak Dye Transfer, Trichrome Carbro, or Duxochrome. Prints from these processes were very costly and were used mainly by professional advertising photographers, not by amateur photographers. AGFACOLOR
Negative Film Type T It’s speed was 10 to 12 ASA(ISO) and it was recommended to find the correct exposure with an exposure meter; in 1951, the Agfa meter was the Lucimeter. The instruction sheet for Agfacolor Type T film suggests making three exposures of the same subject, one at the exposure setting given by the meter, then one exposure at one stop less than the meter reading, and another at one stop more than the meter reading. The best exposure was then selected and with it the correct film speed for that particular camera/exposure meter combination. AGFACOLOR
Negative Film Type K Film speed was 10 to 12 ASA(ISO). With two lamps 4 feet away from the subject, exposures were around 1 second at f5.6. Pictures could also be taken under ordinary room lights, at exposure times of about 3 seconds at f4. It was not possible to achieve a neutral balanced print with daylight and tungsten lighting illuminating the same subject, and prints made from negatives made in this way showed varying blue to yellow colour casts on the same print. Colour filters were not recommended when exposing either type of negative film with the exception of an almost colourless Ultra Violet (UV) filter, Agfa No.K29C. Colour casts due to varying colour temperatures of the lighting were corrected by printing filters and no colour compensating filters, such as the Kodak range of Light Balancing filters, or other makes, were advised. Film
Sizes
Flat film was also made in
Type K artificial light film, but its unknown whether Type K
film was marketed in any other format. Agfacolor negative film for still photography was processed in much the same way as the Motion Picture film equivalent (see above). The first solution, a colour developer, formed the complementary colours in each of the three colour sensitive layers of the film. Unlike the Kodacolor film of that time, there was no orange colour correcting mask formed in the development step. Processed negatives, when viewed, took on a magenta cast. The yellow dyes and the blue-green dyes in the negative could not be seen easily because they were formed in the Ultra Violet (yellow) and the Infra Red (blue-green) regions of the negative film. As the human eye is insensitive to ultra violet and infra red light, the negatives looked magenta. Shifting the absorption of the yellow and blue-green dyes away from the magenta dye improves the saturation of the colours in the printing paper as it ensures the three colour dyes in the negative film do not overlap. Only three solutions were used to process Agfacolor negative film – Colour developer, Bleach, and Fixer. When freshly mixed, the colour developer could not be used for 12 hours, as the chemicals were possibly too active and would produce negatives with too much contrast if used immediately. The three processing solutions were sold in packages to make either 1 litre or 35 litres of solution when made up.
Notes
Agfacolor paper was first demonstrated at a meeting of the German Cinetechnical Society (Deutsche Kinotechnische Gesellschaft) in 1942 at Dresden, but due to wartime conditions, and lack of basic materials, Agfa did not release the Agfacolor negative / positive process until January 1949, and then only to a few laboratories in East/West Germany and later to Switzerland and Russia. Agfacolor film was made at Wolfen, and the printing paper was made at Leverkusen. The negative film, like the early cine film, was available in daylight, Type T, and artificial light, Type K. In the original instruction sheet for the daylight type, the film is rated at 12 to 16 ASA. (Ref: Michael Talbert's own copy). The Agfacolor negative /positive process was introduced into the U.K. in July 1951. Click here to see some magazine advets that date from that time. Until mid-1951, very few people had set eyes on an Agfacolor negative, let alone printed one. Agfa were concerned that if they marketed the process on the basis that everyone was able to purchase the special Agfacolor chemicals, colour paper and equipment to make their own colour prints, great difficulties would arise for the amateur printer from handling, processing, and especially the colour printing of an unknown negative material onto an unknown printing paper. This would have had a detrimental commercial effect on the Agfacolor negative/positive process as a whole. Agfa
processing in the U.K In July 1951, the first four companies to handle Agfacolor materials were (according to Mr.Napthine of Agfa)
Fencolor laboratories Ltd. of 11a, Newmarket Road, Cambridge, are first mentioned as Agfacolor processors in the BJPA of 1953, so its likely they started Agfacolor processsing in 1952. It appears that “University Cameras” of Cambridge sold Agfacolor negative film very early on and maybe took processing and printing orders for Fencolor. The Agfacolor process was capable of giving very good results, provided the film was exposed precisely in the right lighting conditions and the print was made with the correct printing filters in the enlarger. However, in the early days of Agfacolor printing, few people were able to filter an Agfacolor print successfully, so paper wastage was very high, - and expensive! It is quite possible that those who had some experience in making Carbro or Dye Transfer prints in the 1930s or 1940s, or maybe “Ansco Printon” prints, were the most qualified to judge colour casts on the new Agfacolor paper. Those who had made “assembly” prints would have had to learn an entirely new method of changing the colour balance of an Agfacolor print, using glass Agfacolor filters on a black and white enlarger with a filter draw, or working with a “Varioskop F” enlarger with an Agfacolor head. To instruct photographers in the use of Agfacolor negative film, “The International School of Colour Photography” was started at Heath House, Crockham Hill, Edenbridge, Kent. Only photographers who had attended a course at an approved Agfacolor School, such as this, could obtain the genuine Agfacolor chemicals, equipment, and Agfacolor printing paper to process their films and make their own colour prints in their own darkrooms. Students acquired knowledge in using both types of Agfacolor film, plus the processing and printing of Agfacolor negatives. However, upon returning to their studios to put into practice what they had learnt, and finding a general lack of processing and printing facilities in the U.K. at that time, the Colour School also established a colour processing laboratory, namely ”Colour Processing Laboratories”, or C.P.L. for short (1952). At that time, early 1950s, Agfacolor paper was balanced for their unmasked film, and was designated “CN111”. It was a thick, double weight paper with a glossy surface. C-colour, N-normal, 1-double weight, 1-white, 1-gloss. A Hard grade was available from 1952, (CH111). There was also a colour positive film, for making large display transparencies, later known as “Positive Film S” Agfacolor negative film CN17, (40 ASA) was introduced in 1956, and CN14, (20ASA) in 1958. A masked film was put on the market in 1963, Agfacolor CN17M., with a new printing paper for masked colour negatives, coded “CN111M” or later “MCN111”. Michael has access to the processing procedures for most, if not all, of the Agfacolor materials made in the 1950s and 1960s. A service for the processing and printing of the first Agfacolor negative films began in Germany in January 1949. By July 1951, four colour processing laboratories in the UK were handling Agfacolor negative film and making contact prints and enlargements from customers negatives. (see above) Although the Eastman Kodak Company had been making Kodacolor prints with semi-automatic printing machines, using a method of Tri-color printing, since 1942 (see: Early Kodacolor Print Materials), the Agfa company preferred a different approach. Agfacolor prints were made by a method known as “White Light” printing, in which the colour cast on a test print was removed by inserting coloured filters into the light beam of the printer or enlarger. Although this web page has already described the colour printing filters used in Motion picture printing (see above), the Agfacolor printing filters for use in printers and enlargers were slightly different. In 1951, Agfacolor Printing filters for use in printers and enlargers were manufactured as square glass sheets, in 6 sizes, from 2¾inch square for enlargers taking 35mm negatives, up to 11¾inch square for vertical or horizontal enlargers designed to print large sheet film negatives. All sizes of printing filters were available in the three subtractive colours i.e yellow, magenta and blue-green (cyan) in a range of varying densities. The lowest colour density was nominated as a “5” unit filter and then the filter densities progressed in 10 unit densities up to and including 100, the highest colour density. Thus a set of filters would consist of 11 in each colour, making 33 separate filters (in 1958, a set of 24 gelatine Agfacolor printing filters was manufactured specifically for amateur colour printers, 8 filters in each colour). The “100” density filter was marked as “99”, so a six figure code could be used when writing the filtrations used in colour printing. The filtrations used for each colour print or test print were written in the strict order of “Yellow, Magenta, Cyan”, the colour Blue-Green was (by then) known as “Cyan”. The filtration 00 99 45 would consist of: no yellow filters, a 99 magenta filter, a 40 cyan filter, and a 5 cyan filter. A simpler way of writing filtrations was to abbreviate the designation for the filter not being used by using a line. 00 99 45 became – 99 45. This is said: "Stroke, ninety-nine, forty-five". For Agfacolor printing, an enlarger with a filter draw was an essential requirement, and it was possible to modify a black and white enlarger for colour printing by fitting some kind of filter draw between the light source and the condensers. The sets of 33 colour printing filters were supplied in a wooden case, which incorporated a small hand torch, fitted with a light which was safe for Agfacolor paper types CN111 and CH111, so a filter from the case could be selected in a darkened room without fogging the Agfacolor paper. On each filter was printed a black/white edge, on which the denser the filter, the longer was the printed white section compared with the black section. It was then easy to tell if the filters were not in order of density when they were put back in their case. Enlargements from colour negatives were made in exactly the same manner as enlarging from black and white negatives, apart from the use of the colour printing filters. The colour printing filters were used to correct any colour cast by inserting a filter of the same colour and density of the cast.
It is never necessary to print with all three colours of filter within the enlarger since yellow, magenta and cyan filters, if all used together, simply cancel each other out. AGFACOLOR
Enlarger Heads Instead of a whole array of individual glass colour printing filters of varying densities, a special printing enlarger “Colour Head” was equipped with one “99” (100) density glass filter in each of the subtractive colours which could be gradually introduced into the light beam of the enlarger. Three knobs on the outside of the colour head were provided for moving the “99” filters more or less into the light beam. Above the knobs was a graduated scale from 0 to 99. When half the filter was across the light beam the scale registered “50”, and so on. The filtration of any colour print could now be corrected to any degree down to a unit of “1”, whereas the smallest change when using glass filters was a unit of “5”, the smallest density glass filter made. If the colour cast on the test print was so strong that a higher filtration than “99” was needed to eliminate the cast, a fourth knob, situated in the centre of the colour head was pulled out to introduce a further “99” filter in any one of the three subtractive colours. The first Agfacolor Heads to be manufactured were provided with one “99” supplementary filter but later, in the early 1950s, the Heads were modified to incorporate one pull-out knob for each colour. The maximum filtration which could then be utilized was 210 units in each colour. The rotary knobs were able to be turned past the “99” mark giving another 10 filtration in each colour. This was to allow for a certain amount of fading of the filters. The pull-out knobs were known as “stops”, and the rotary knobs were known as “dials”. |
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
The lamp used in the Agfacolor Head was a 250 watt tungsten bulb. This bulb also illuminated the scales above the rotary knobs so that the filtration could be adjusted in the dark-room. The light was thoroughly mixed before reaching the condensers of the enlarger. The “Agfa Varioskop” was the first enlarger to be fitted with an Agfacolor Head, although the Head was modified to fit other makes of enlargers. One of the first companies to fit an Agfacolor Head to their enlargers was De Vere, who had started making enlargers for black and white printing in 1947. |
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
The author has had considerable experience of making prints using Agfacolor Heads and can add the following comments.
Compensation
for exposure times when using Agfacolor glass colour printing
filters Agfa produced tables of exposure
factors for calculating exposures for all possible variations
in filtrations. A print exposure made with no filters in the filter draw (zero print) is judged to have a Blue/Magenta cast and glass filters of 120 Magenta and 90 Cyan are placed in the enlarger filter draw to correct the colour cast. ( -- 120 90) The original 'correct' exposure with no filters was 8 seconds at f/11. The exposure factor given for those particular Magenta and Cyan filters is 7.4. Therefore the print exposure has to be increased by 7.4 times the original exposure. Thus, 7.4 x 8 = 59.2. The print would have been exposed at 60 seconds at f/11. The length of time could, of course, be reduced to 30 seconds at f/8 When using the Agfacolor head the exposure factors were sometimes less. In this case, the exposure factor for 120 magenta and 90Cyan is 6.6. Glass filters generally required more compensation in print exposure than the colour heads because of a small amount of light reflection between the filter surfaces in a stack of glass filters placed in a filter draw. Exposure factors for the glass
filters ranged from: When adding glass filters, or dialing up filters on the Enlarger Colour Head, the exposure time was multiplied by the appropriate exposure factor. When removing glass filters, or dialing down, the exposure time was divided by the appropriate exposure factor. |
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| The Agfacolor Mosaic Filters | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
In the early 1950s, the most difficult aspect of making any successful colour print, was deciding on which printing filters to place in the filter draw to eliminate the colour cast. Two decisions had to be made.
Of course it was quite possible to expose many test strips with different filtrations and exposure times on a trial and error basis in the hope that one or other of the tests might show the correct colour balance. This takes much time and uses up a lot of colour printing paper. hence, Agfa invented a faster method of arriving at the correct filtration while exposing only the minimum of test strips. |
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
The Agfa Mosaic filters consisted of different filter combinations, available as three different filter groups. Each mosaic filter contained 36 different filter combinations in a chequer board fashion. One mosaic filter was of Yellow – Magenta filtrations, from no filtration to 99 99 –. Another mosaic was of Yellow – Cyan filtrations, from no filtration to 99 – 99. The third mosaic was of Magenta – Cyan filtrations, from no filtration to – 99 99. Each mosaic filter was available as a glass filter for placing on top of a piece of Agfacolor paper. A Mosaic print was made by “printing” the Mosaic filter onto the paper with the negative in the negative carrier. Procedure for using the Agfacolor Mosaic filters The principle of colour balancing
a print from a colour negative using subtractive filtration,
is as follows:
Hence, if the "zero" test print had a Green cast, then another test was exposed, this time with the Yellow – Cyan mosaic filter placed on top of the printing paper (i.e. adding Yellow - Cyan filtration) and exposing for twice the time as assessed by the “zero” stepped exposure test print. The Yellow – Cyan Mosaic was graduated in 36 Yellow and Cyan filtration combinations at 20 unit intervals, for filtering out colour casts from Yellow to Green to Cyan (see diagram). The exposure time was doubled to compensate in general for the density of the different filtrations in the mosaic filter. Each mosaic filter repeated the same group of 36 different filtrations eight times, so that a single exposure using the mosaic would show the effect of the mosaic over 8 different parts of the print. Each filter measured 4¾ inches by 2½ inches. After processing, the Mosaic print would show a range of colours from Blue to Magenta to Red. A filtration for exposing the final print could be assessed by choosing the most neutral coloured square, repeated eight times over the Mosaic test print. A special mask was available, which isolated the “assessed” filtration in the eight sections. It was perforated with eight square holes, and when placed on the Mosaic print and one square hole lined up with a selected filtration, the other seven holes would show the result from the same filtration in the other seven sections. Having found the filtration for that particular square, (see diagram), those filters could be placed in the filter draw, the exposure time calculated from the exposure factor table, based on the “zero” print exposure, and the final print exposed. In practice, it is likely that another test print would be exposed, as the Mosaic filters were made at 20 unit intervals and so an estimated 'in between' filtration might have to be made. |
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| If the colour cast on the “zero” print was so strong that the Mosaic print (as in the example) was still Yellow, or Cyan, or Green in the 99 – – square, or the – – 99 square, or the 99 – 99 square, then another trial Mosaic print was exposed, but this time with a 99 unit filter of the same colour of the cast placed in the filter draw. When the Mosaic print was assessed, it was remembered that each, say, yellow filtration had been increased by 99 units. For example, the 40 – – square would now be 140 – –. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
The disadvantages of the mosaic filter system were:
It should be noted that a saturated area of any colour is extremely difficult to filter to correct balance because that area of the print may look acceptable at a number of differing filtrations that would not be representative of the picture as a whole. Because of these disadvantages, the mosaic system was almost obsolete by the end of the 1950s. A far better method was to make one test strip from a new negative at a filtration based on previously printed negatives and then, according to the colour of this test strip, make three or four more tests with different estimated filter values. It was quite possible that one of the tests would be close to a neutral colour balance. Another two estimated test strips would likely bring the correct filtration to within 10 filter units and a final, correctly balanced, print could then be made. In the long run, this method probably wasted less paper on test prints than the mosaic system. Agfacolor
Comparator The Comparator was equipped with a set of Agfacolor printing filters which could be set at the filtration for the “known” Agfacolor negative (one that printed to a neutral balance), and another set of printing filters which were adjustable to match the colour of the two negatives. Both negatives were viewed at the same time, and the filters were changed under the “unknown” negative, (the negative that was to be printed), until the colour of both negatives looked the same. The value of the printing filters used to match the colour of the negatives was then used to make the final print. Example:-The “known” Agfacolor negative had been printed at a filtration of -- 40 40 and this had produced a satisfactory print. When the “unknown” negative was matched in colour to the “known” negative, the matching filters were -- 85 90, then this filtration was the correct one for the final print. By adding blue filters, almost
50 blue, this meant that the “unknown” negative was
yellower than the “known” negative. If the “unknown”
negative had been printed at a filtration of – 40 40, then
the resulting print would have printed bluer, the amount of extra
yellow in the negative producing a blue cast. By adding a blue
filter, approximately 50 blue, or in colour printing filter terms,
45 Magenta, 50 Cyan, ( -- 85 90) , this filtered out the blue
cast. The 'Colorax' and other devices Other gadgets, or devices were the “E.K. Strip printer” and the “Colormeister”. By the early 1960s, most of these gadgets were rendered obsolete. More sophisticated methods evaluating colour negatives were appearing on the market such as electronic densitometers which, if correctly calibrated, could give a fairly accurate filtration from an unknown negative in seconds. One of the best densitometers made was the “Macbeth Quantalog”, made by the Macbeth Corporation, Newburgh, New York, U.S.A. Another was the “Welch Densichron”. These newly marketed densitometers drastically reduced the amount of tests prints made in hand enlarging. 'Hand enlarging' is a term in the photofinishing industry referring to enlargements made manually with an enlarger, as opposed to small prints made on an automatic machine, as is usually the case with amateurs’ negative films. When the Agfacolor negative/positive process was first marketed, it is believed that the filter corrections for Agfacolor negatives were aimed, for best correction, at a zero filtration. That is to say, when a printer made a first test print he would have exposed that test print with no filters. He then may have made another test using a Mosaic filter, chosen according to the colour bias of the first test. Filtrations higher than 100 (99) were deemed unlikely. By the mid-1950s, it was noticeable to Michael Talbert that filtrations for Agfacolor prints were generally moving in a Magenta/Cyan direction, the yellow filter hardly ever being used. Agfacolor CN111 and CH111 papers would have been in use at this time. John Vickers, author of the book, “Making and Printing Colour Negatives” published in 1959, gives filtrations mainly in Magenta and Cyan. In the late 1950s, Kodak Colour Print paper Type C and the later Ektacolor paper, (see early Kodacolor web page), were balanced for use with Yellow and Magenta filters, possibly due to the fact that Kodacolor and Ektacolor negative films were of the “orange mask” variety. Agfa introduced their first “orange” masked negative film in 1963, being CN17M, and with it a new printing paper, CN 111M, the latter balanced for use with masked negatives using, like the equivalent Kodak papers, Yellow and Magenta filters to correct the colour balance. By 1964, the paper became known as MCN 111. Grundzahl
Figures Example:- If a satisfactory print was made on Agfacolor
paper Batch A at a filtration of 00 70 60. Lets assume the “Grundzahl”
figures for paper Batch A were 00 20 30 and that the “Grundzahl”
figures for paper Batch B were 00 50 50.
The figures were only a guide and a lot depended on the age of the colour paper and how it had been stored, so the figures were not always reliable. The speed of Agfacolor paper didn't vary significantly. The “Grundzahl” figures in the worked example (above) are taken from CH 111 paper. The Agfacolor CH 111 paper box shown left has the Grundzahl figures 00 Yellow, 50 Magenta, 50 Cyan. Packets and boxes of the later MCN 111 paper were stamped with Yellow and Magenta “Grundzahl” figures, with Cyan left as 00, i.e 70 50 00.
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
Batches of experimental Agfacolor paper were used for making colour prints as early as 1942. The following is a very early paper process, dating from 1947.
Notes. This process was for Agfacolor paper CN111, and for the later CH111.
Notes on the above processing procedure.
As late as 1956, Jack H. Coote mentions the above Agfacolor print process in his book “Colour Prints”, first edition, published in April 1956. By then, Agfa were using a more simplified process for their Agfacolor paper. Substitute formulae for processing Agfacolor paper have been given by R.J. Finn in the British Journal of Photography Almanac of 1954. The processes are not identical to the procedures given by Agfa. Finn’s colour process involves a “Stop-Fixing Bath” or a “Fixing Bath”, in place of an ordinary stop bath and some of the wash times are longer. Finn also warns prospective amateur colour printers about Red Fog, which can occur in (his formula) the Bleaching bath, hence a long wash up to 15 minutes, before the Bleach. The third step of his procedure he called a Stop-Bath, but the formula is one for a Fixing Bath ! |
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
By 1954, print processing had reached the stage where a combined Bleach and Fixer were being used in processing Agfacolor Paper. This reduced the number of chemical baths to four and washes to three, but only reduced the overall processing time compared to the 1950 sequence by four minutes. !954 Processing Sequence for Agfacolor Paper CN111 and CH111
Notes on the above processing procedure.
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
From 1952, official Agfacolor chemicals and printing materials were available in the UK but were not sold to Amateur photographers unless they had attended a course of instruction at the Agfacolor School (see above, International School of Colour Photography). In 1958, the processing and printing of Agfacolor materials had become straightforward and reliable enough for Agfa to release the chemicals for processing the negative and positive materials plus Agfacolor paper for sale to the general public without the need for attendance at an approved Agfacolor School. Packs of 1 litre chemicals for processing Agfacolor negative material and Agfacolor paper, plus various sizes and quantities of Agfacolor paper became available for sale to the Amateur photographer. For processing negative films, the Colour developer, Bleaching bath, and Fixing bath were made up from powders to be mixed with water. A liquid colour developer, especially suitable for processing Agfacolor CN-17 films in the Agfa Rodinex developing tanks was marketed as an alternative to the usual 1 litre powder developer pack. The liquid developer could be diluted to suit the capacity of the Rodinax developing tank being used, and the developing time varied according to the dilution. CN-17 film was developed for 7 minutes at a 300ccs total dilution (stock solution of developer plus water), extending to 13 minutes at a total dilution of 700 ccs. A fourth solution, the Magnesium Sulphate bath, was necessary for the processing of Agfacolor negative film. This was “user make-up”, and consisted of 3% Magnesium Sulphate, or 30 grams per litre. It was also advised by Agfa to add 30ccs of freshly prepared developer to each litre of Magnesium Sulphate bath. Agfacolor Negative Film Processing
This negative process differs little from the 1950 negative processing sequence apart from the fact that the Magnesium Sulphate bath was now considered an essential part of the processing procedure. Notes.
Colour
Negative Printing A set of filters consisted of Yellow, Magenta and Cyan in seven densities from 5 to 99 (100) in each colour. There were two “99” filters of each colour, ensuring that heavy colour casts could be corrected in the printing operation. Later sets of filters were supplied with a small Agfacolor print and the negative of this print. The negative was printed onto Agfacolor paper and the print was filtered to match, as near as possible, to the print enclosed with the filter set. In this way it was possible to ensure that processing was satisfactory with regards to colour balance and contrast. Any errors in exposing and processing, which might have gone un-noticed, would show and could be corrected. The set of 24 filters, size 7 cms. square, were intended to be used in a filter draw below the condensers of a black and white enlarger. If the enlarger had no filter draw, it was possible, ialbeit somewhat inconvenient, to make a mask out of black cardboard, balance the mask on top of the condensers, and then place the filters on top of the mask. This method could be used for the occasional printing session, but it was far better in the long run to obtain an enlarger with a filter draw. Voltage
Fluctuations |
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
 
|
Agfa published an “Agfacolor Manual”, specifically aimed at amateur photographers or beginners in colour printing. Entitled:- “Agfacolor Fibel, Leitfaden zur Selbstverarbeitung von Agfacolor Negativ – Positiv”, meaning “Agfacolor Manual, Introduction to “do – it –yourself” processing of Agfacolor Negative/Positive Materials”. The first edition was published in German, in 1958, but it was later published in English, and ran to two more editions before being completely re-written and up-dated and published as “Agfacolor User Processing”, in 1972. The first 1958 German edition gave very comprehensive instructions on how to process Agfacolor negative film and how to make prints on Agfacolor paper. Included in the book were tables for negative and print processing sequences, and filter factor charts, as well as a colour balance comparison chart of one neutrally filtered print surrounded by six “off colour” prints, each varying by 50 units of cyan, magenta, yellow, red, green and blue. At the back of the book there were five “tear-out” processing data and filter factor tables for mounting onto cardboard and hanging up in the darkroom for instant reference. Printed on the last page of the manual were lists of Agfacolor films, Agfacolor papers, chemicals and filters which were available for sale to the amateur photographer. |
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
A complete set of chemicals, suitable for making up 1 litre quantity of each of the four print processing solutions, was available for sale to amateur photographers. The collective name for the set was: Pa/Satz. The processing solutions were Developer, Stop-fix, Bleach-Fix and Anti-Fade bath. Each solution was made up from powders to be mixed with water, but the Anti-Fade bath required the addition of Formalin which had to be obtained separately. The chemicals were also sold as individual units. Processing
Sequence for Agfacolor Papers CN111 and CH111
Total time without drying:- 49½ minutes. Notes:
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
This label dates from 1960, although the design of the larger label may date from the 1950s. Agfacolor paper CH 111 was first introduced in 1952. 
CH111: Colour, Hard (contrast grade), Double Weight (1), White, (1), Glossy (1). This paper was for use with soft contrast negatives, and gave good results with slightly under exposed negatives. The little label above the main label reads: “Only Pa 1/60 Developer to be used”. Pa 1/60 was a colour developer introduced in 1960. It was non-irritating to the skin, less likely to cause dermatitis, and produced brighter and more brilliant colours. |
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
MCN 111 paper was introduced in 1963 for making prints from the then new Agfacolor CN 17M sheet film, Agfa’s first masked negative colour film. This label dates from 1964. This paper was for use with Normal contrast negatives. On later labels storage information was printed underneath the cyan panel. It was recommended that MCN 111 paper was stored at 10°C (50°F) or lower to extend the keeping properties of the paper. The later labels stated: “Cool Storage below +10°C” in four languages. |
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
A new Agfacolor Negative film
was introduced in 1956. This film replaced the earlier Agfacolor
types T and K films (see previous, above). CN-17 film had a speed rating of 40 ASA, (ISO), or 17 DIN (German Speed rating). In 1956, it was one of the fastest colour negative films available, a distinction it shared with Pakolor PK-24 film, also rated at 40 ASA. The average exposure in daylight was approximately 1/125 at f5.6. As the film had no orange colour correcting mask, it was easy to make good black and white prints from the negatives. Processing followed the same procedure as with the previous Agfacolor negative films, but the development time was slightly longer with the new film. Agfacolor CN-17 Universal film was first sold in rollfilm sizes 120, 620, and 127, “Karat” cassettes of 12 exposures, and 35mm cassettes of 20 exposures. Later, 35mm cassettes of 12 and 36 exposures were available. Many sizes of sheet film were obtainable, including a 4inch by 5inch format (see picture). |
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
In 1963, an orange masked version of CN-17 film was produced in sheet film format only, known as Agfacolor CN-17M, but it was short lived and was withdrawn from the market a year later. It had a film speed of 40 ASA (ISO). An improved type of masked film was introduced in 1966, called “Agfacolor CN-17S" (S for Special), with a film speed of 40 ASA (ISO). This film was available in roll film sizes, 35 mm cassettes of 12 and 20 exposures, and Agfa “Rapid” cassettes. CN-17S film is listed in the British Journal of Photography Annual (BJPA) for 1968 under “Colour Materials for still Photography”. In the column “Sizes Available”, the “BJ” gives a sheet film format for CN-17S. However, Michael thinks this maybe a mistake, as he can find no other reference to a CN-17S sheet film in any other of his historical Agfa or Agfa Gevaert records. Agfacolor CNS film was introduced about May 1968 as a replacement for CN-17S. CNS was obtainable in the usual roll film sizes, 35mm in 20 and 36 exposure cassettes, “Rapid” cassettes of 16 exposures, and “PAK” film cassettes of 12 and 20 exposures. “Pak” film was equivalent to 126 size cartridges, suitable for the Kodak range of “Instamatic” cameras, plus other cameras designed to take 126 size film. Agfacolor CNS film had a speed of 80 ASA (ISO), which at that time matched the speed of Kodacolor X film. As far as Michael has been able to find out, Agfacolor CNS film was never made in any sheet film formats. Despite these three new films being introduced, the original Agfacolor CN-17 Universal film remained on the market until the end of the 1960s. By then the printing paper for unmasked negatives was no longed being manufactured (Agfacolor CN111), but good prints could be made on Agfacolor paper MCN111, and later versions of it, by incorporating an unexposed but processed piece of Kodak Ektacolor sheet film or Kodacolor rollfilm with the printing filters, or even with the negative itself, when making prints on Agfacolor MCN paper. This alleviated the very high yellow and magenta filtration values necessary when printing an unmasked negative onto a paper intended for use with masked colour negatives. On a personal note, the author first used CN-17 film in 1968, and was processing the film and making prints from it in 1969. In 1970, he remembers taking pictures on several out-dated rolls of 120 film, as by then in-date film was a unobtainable, CN-17 having been replaced by Agfacolor CNS. |
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
Michael Talbert started making colour prints in 1969, using Kodak Ektacolor Commercial paper. He was a photographic colour printer in the 1970s, printing colour negatives mainly onto Agfacolor paper. He also had experience using about 10 types of Kodak paper, plus other makes, Gevacolor, Fuji, Paterson, Konica. Michael now sets up and takes “Retro” fashion pictures, but prints them digitally. |
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| UFA, Universum Film AG, (originally
Universum Film Aktiengesellschaft): The following is taken from Wikipedia: Universum Film AG, (originally Universum Film Aktiengesellschaft) better known as UFA or Ufa, was the principal film studio in Germany, home of the German film industry during the Weimar Republic and through World War II, and a major force in world cinema from 1917 to 1945. After World War II, UFA continued producing movies and television programmes to the present day, making it the longest standing film company in Germany. |
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
Wolfen and ORWO: As far as Michael Talbert can ascertain, Agfacolor paper was only made at Leverkusen, possibly from the end of WWII, and then marketed in Europe as from 1949. The Wolfen plant continued to manufacture negative film branded with an “Agfa” label until 1964, from then on the film was branded “ORWO”. ORWO stands for “Original Wolfen”, and by the mid 1960s as many as five different types of negative film, plus three transparency films, were manufactured at Wolfen. The change in brand name may have been due to the fact that Agfa and Gevaert joined forces in July 1964. Both companies continued to make colour film and colour printing paper with their own brand labeling for a year or two after 1964, and by the late 1960s film and paper products were labeled “Agfa-Gevaert.” “Gevaert” was a large Belgian photographic material manufacturing company founded by Lieven Gevaert in 1894. The company’s plant at Mortsel made colour film and colour printing paper as from the early nineteen fifties, initially mainly for D&P laboratories. The company started marketing their colour film and colour printing paper in the U.K. in 1953, with the sizes of prints and prices being similar to Agfacolor at that time. |
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
The
“Grundzahl” figures were always printed with a “00”
indicating the filter not required, i.e. 00 20 30 (Batch A) and
00 50 50 (Batch B) in the above example.
MCN
111 Masked, Colour, Normal (grade), Double Weight (1), White, (1),
Glossy, (1).
 |
 |
|
|
|