C-41 at Room Temperature

[Nick_3536]

Fotochem for one.

http://www.jdphotochem.com/

[Ron Mowrey]

A couple of comments are due here.

Leuco dyes are formed in C-22 and are converted to the final dye in the ferricyanide bleach bath. In C-41, the full colored dyes are formed in the development step. This alone makes the two films and processes basically incompatible.

C-22 and older C-41 films required formalin to stabilze the dyes and residual couplers from interacting and causing fade. Newer C-41 films don't need formalin but it can be used, as a secondary effect of formalin was as an antibacterial/fungicide for the film. The new final rinse helps prevent growth of bugs in the film during storage.

In the case of the hospital problem with aldehydes, it was due to glutaraldehyde in the X-Ray process which is apparently quite toxic in spite of the higher boiling point compared to formaldehyde.

Now to the final item... I've talked with Pat Dignan lo these many years ago when he was still with us. I advised him to stay away from CD-4 for processing color prints, and I advised him not to use 2 bath processes. He took the first piece of advice but not the second.

My reasoning for the advice on two bath C-41 developers is this. Color negative films are very thick, sometimes with 14 layers or more. And, between versions and manufacturers you will find that the number of layers, their position and their thickness varies. Along with this, the films contain DIR couplers to control the color reproduction and image structure.

The entire setup is based on control of diffusion through these layers and does not always work out the same when you change the developer or the development conditions. I have seen this happen. At best, the cyan layer on the bottom is under developed, or the yellow layer on top is over developed (or both). At worst, you have total crossover, fog, speed mismatches and etc.

Well, the final result is this. If you get it to work with film A under a given set of conditions, thats fine, but those condition will probably not work for film B and you will have to retune the development time(s) and temperature. In other words, with the Dignan developer (designed for a thicker C-41 film of over 10 years ago) you would have to test it with every film you use and get an optimum condition, and this is not a guarantee, just a guesstimate. Today's C41 films are drastically different than those of just 10 years ago.

Good luck.

Ron Mowrey

[jetcode]

Anyone want to share how to manage and dispose of C41 chemistry in a home lab using well water and septic? The lab I'm using is nicking me $6 a neg for 4x10 because it takes up an 8x10 slot in their tank. I think I can save money since I am already wired for B/W processing using a Unicolor drum. Any recommendations for starting up this process?

[Gary L. Quay]

Where I live, household hazardous waste can be taken to a transfer station for free. They figure it's better to make it a free service than having folks pouring it down the drain. I save old developer, selenium toner, etc, in the bottles that I get my distilled water in, and take it there. I take my fixer to my camera store, and they take out the silver. I wouldn't dump the stuff down the drain, especially in a septic system, because it'll kill off microbes that make the septic system function, as well as potentially pollute the ground water.