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Tuesday, June 12, 2012

Like processed in C-22

Old color films were processed according to C-22 process, that required several chemicals but the main difference was the color developer, instead of CD-4 it used CD-3, still used for color slides in standard process E-6. Another important difference is the change of the bleach bath in witch entered  the environmental pollutant Potassium Ferricyanide replaced with Fe(EDTA), ferric ethylenediaminetetraacetate, as far as I could determinate.
Of course there were changes in photos quality, some of the photos treated in C-22 were very different from the modern ones, with their vivid colors. But not only the developer was other, the bleach bath determines also the color quality. I discovered in the internet this photo, among others, here.

Photo from the 70's
This was for me an important issue, I can see that some of my first attempts to develop color photos in a different way, gave also similar results, where we hardly can talk about color.

One of my first attempts
I have been using CD-4 as color developer, but the bleach I used was based a recipe of Franz Dietrich,1988, with Potassium dichromate and Sulfuric acid, both of them easy to get for me. Potassium dichromate and Sulfuric Acid (see Recipes, Caffcol I) require careful handling but the solution is very weak, I have been using the recipe in a 1:5 dilution with water. So, the working solution is not such a problem to deal with, care must be taken when dealing with the pure substances, gloves, fresh air mask and googles are recommended.

But this color is, for me, mainly a matter of the bleach used. So, if you want to achieve a 70's look, try this bleach, but be very precise in the time because it may bleach completely your film if you give it time to act.I have been working with 3 minutes bleach constant agitation to prevent uneven bleaching like in the photos above.

Another example pf a photo of the 70's but made in 2012




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