Has anyone ever developed colour film using a black and white developer instead of a colour developing agent?
I don’t mean developing it as black and white film, but actually swapping the developer.
I don’t quite get it either. What’s the difference?
I’d be interested to know whether colorants form or not. After all, some black-and-white developers do use
derivatives of color developer substances as the development agent (p-phenylenediamine).
Someone once told me that the pH value (and presumably also the concentration of p-phenylenediamine) determines whether the colorants form. I had to try it out for myself anyway and developed a C-41 film in Emofin, which is also based on p-phenylenediamine. Of course, no colour image emerged, just a black and white one. I didn’t bleach out the silver, but if colour had formed, it would still have been visible in the scan.
Furthermore, I’d be interested to know how it’s ensured that transparency films don’t form
colorants during the initial development.
It’s quite simple – the primary developer is a black-and-white developer that is incapable of forming colorants. It merely ensures that a negative image is present, so that the silver halide in the emulsion is no longer light-sensitive during the (possibly chemical) secondary exposure. This process creates a negative of the negative, which produces the colour positive image during the subsequent colour development. The subsequent Bleach bath converts the black metallic silver back into silver salt, which the fixer then washes out (or simultaneously, if a bichromate bath is used). In the primary development, only a silver (black and white) image is produced; in the secondary development, the dye formation occurs, which overlays the silver image until bleaching and fixing.
What I’d also like to know is what requirements the black and white primary developer must meet, or whether I can use any black and white developer for this purpose, e.g. to influence density (push/pull) and contrast. Or whether using such a primary developer might chemically destroy the secondary developer, e.g. due to residues in the emulsion... In other words: can I develop a transparency more or less correctly using Rodinal and a C-41 kit, or will I just ruin the second/colour developing agent in the process? I’d also need to make sure the primary developer is thoroughly rinsed out before I perform the second exposure, so that everything doesn’t turn black during the second exposure :) – I’ll have to give it a go sometime...
Peter.
