PROCESSING COLOR FILM STEPHEN P. MARION Brooklyn College, Brooklyn, New York
T z o s E familiar with the processing of Anscochrome Color Films know that some of the solutions last only a week or two. Actually the best results are obtained from freshly prepared solutions. For this reason it is convenient and economical to prepare the necessary solutions from individual chemicals. These formulas have been assembled from various sources, have been modified and tested, and good results are obtained. A brief review of the important points of technique together with some of the pitfalls to be avoided are given. With one important exception liberal variations in timing will still give satisfactory results. Since 500 ml. is a convenient volume for 35mm.-tanks, which volume will process up to 3 rolls of film, the formulas are stated on this basis. Step 1. First Developmat Water (20D30'C.). . . . . . . . . . . . . . . . . . . . . . . . . Metol (Elon, Pictol, Photol). . . . . . . . . . . . . . . . . Sodium sulfite,. anhydrous. . . . . . . . . . . . . . . . . . . Hydroquinone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Sodium carbonate, monohydrated.. . . . . . . . . . . . Sodium thiocyanrtte. . . . . . . . . . . . . . . . . . . . . . . . Potassium bromide. . . . . . . . . . . . . . . . . . . . . . . . . Water to. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ~
:375 ml. 1.5 g. 25.0 g. 3.0g. 20.0 g. 1.0 g. 1.0 g. 500 ml.
The optimum developing time is about 21 minutes at 20°C. Uniformly good results are obtained when the time of develop ment is between the limits of 18 to 24 minutes. Less than 18 minutes constitutes underdevelopment which will be evident by purplish tones. This first step is critical in the direction of underdevelopment, and if an error must be made it is better to overdevelop than to underdevelop. During this first development, and in fact through the following steps, frequent agitation is advised.
Step 8. Shmt Stop Water.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 375 ml. Glacial acetic acid. . . . . . . . . . . . . . . . . . . . . . . . . . 5 ml. Sodiumaeetate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.0g. Water to . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 500 ml.
Step 8. Color Development The film is developed in the color developer for 18 to 20 minutes a t 20°C. This developer is compounded as follows: Water (20'-22T.). . . . . . . . . . . . . . . . . . . . . . . . . . 375 ml. Diethyl paraphenylene diamine. . . . . . . . . . . . . . 2.0 g. Sodium bisulfite. . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 . 9 g. Sodium carbonate, monohydrated.. . . . . . . . . . . . 35.0 g. Potassium bromide. . . . . . . . . . . . . . . . . . . . . . . . . 0.5 g. Water t o . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 500 ml. The dye coupler N,N-diethyl paraphenylenediamine is Easb man Organic Chemical No. 1374.
Step 7. Step 8. Sfep 9. Step 10.
Shmt Stop--Identical with step 2 Hardma-Identical with ~ t e p 3 Wash-Identical with step 4 Bleach
The film, in spite of the color development,, does not show a transparency in full color. I t is necessary to remove the original black silver deposit by bleaching it, and then removing it. Bleaching should take a b u t 6 minutes and this bath will keep for some time if stored in a glass container. It may he used until the time for bleaching becomes excessively long. Water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 375 ml. Potassium ferriqwnide. . . . . . . . . . . . . . . . . . . . . . 35 g. Potassium bromide. . . . . . . . . . . . . . . . . . . . . . . . . 7.5 g. Disodium hydrogen phosphate. . . . . . . . . . . . . . . 7.0 g. Sodium bisul6te. . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 . 0 g. Water to... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 500 ml.
Step If.
Wash
The film is washed for several minutes in running water or until no yellow color from the potassium ferricyanide is imparted to the wash water.
Slep 1% Fixing The bleached image is now removed with sodium thiosulfate. Do not use the acid fixing solutions normally used for black and white processing. Water. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 500 ml. Sodium thiosulfate.. . . . . . . . . . . . . . . . . . . . . . . . . . . 100 g.
The film is treated for 2 or 3 minutes in this short stop. This bath is saved for use in step 7.
This bath may be used until the fixing time becomes excessive, say longer than 6 minutes. The film should now appear in full color.
Slep 5. Hardenw
Slep IS. Wash
Water.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 500 ml. Potassium chrome alum. . . . . . . . . . . . . . . . . . . . . . . 15 g.
Ten or 15 minutes in running water. It is then rinsed in a 0.1% detergent solution (Glim or Joy) and hung up to dry.
A +minute immersion in this bath will do. This bath is saved for step 8.
The temperatures of the solutions and wash water should be as close to 20°C. as possible. Actually, except for the first and color developers the temperatures are not too critical, and neither is the timing of the operations. However any emulsion, whether color or black and white, is a delicate item and successive extremes of temperature can do no good to either. If the final film is a uniform copper red instead of a natural the bath was quite enough. Adding a little more of the phosphate and re-treating
Step 4.
Wash
The lights are turned on and the rest of the processing can be done in room light. The film is washed for 5 minutes in running water.
Step 5. Second Exposure The film is now re-exposed to a No. 2 floodlamp for about 1 minute on the face side and 1 minute on the hack side, holding the film about 3 feet from this light.
VOLUME 34, NO.
9, SEPTEMBER, 1957
441
the film will usually bring about the correct colors. A second quick hypo rinse and washing will be necessary. With these solutions, if the first development has been carried out properly, the color development stage even when carried out to 30 minutes will still give good results. Obvious overdevelopment in the first developer
will give weak washed-out results in the final stages. Little can be done to correct this. Further experiments along this line may be taken by trying other dye coupling agents in the color developer. Dimethyl paraphenyleuediamine can be used satisfactorily.
JOURNAL OF CHEMICAL EDUCATION
