I dont think so. Most or all of the orange mask is incorporated in the base; no way to get it out without destroying the film itself.
No no noI'm perfectly fine doing proper B&W and proper C41, but my curious engineer's brain just wanted to know. Donald answered my question perfectly, thank you everyone.
Although now I'm curious about the opposite: can I use C41 developer to develop B&W?
Why does this keep coming up. Color film has a Grey or slightly Blue base. the orange colour comes from Yellow and Magenta couplers in the film which correct for dye absorption. Don't believe me? take a scrap colour film end and scrape off the emulsion like you were going to make a splice.
4-aminophenol (stuff in Rodinal) is a type of colour developer, and I would say metol is too, and possibly phenidone. They all have amine groups which results in dye formation. But only when there is no or very little sulphite in the developer.
This effect -- formation of dyes on oxidation -- occurs with at least p-aminophenol and metol; that's what you're seeing when old developers turn brown with time. The dyes that form are slightly weak in cyan/blue, so the overall color is yellow/brown. I'm rather surprised you can see the colors in unbleached C-41 film, however; I'm pretty sure the dye couplers in the emulsion aren't correct for the dyes formed by developers outside the PPD family. Might be that the dyes are weakly coupling and the bleach breaks them loose from the couplers, allowing them to wash out. You might (if/when you get back to it) explore using a formaldehyde based stabilizer before bleaching. This used to be a required step (though, with correct dye couplers, applied after bleach and fix steps, as part of the final rinse) for C-22, and C-41 until around 2000.
Of course, it might also be that the dyes are coupling to the developed silver some way, which gets removed during bleach and fix -- but that wouldn't explain getting roughly correct-looking colors (the dyes should be random in that case, producing a brown or black image).
Obviously, this isn't going to replace proper CD-4 based color developer, but it's a cool and interesting "this gave an image" sort of finding...
Those two examples were scanned as a reflective iirc. Given the file name of the first one, it appears I would have developed, bleached and not fixed.
There is a non-trivial chance, that sulfite destroys the dyes you created that way. It would be interesting to see, what remains of these dyes, if you fix with pure Sodium Thiosulfate, or even with Sodium/Potassium/Ammonium Thiocyanate.
Your responses are always exceptionally succinct, unambiguous, and always readily understandable by non chemists like me. - David LygaColor developers are generally poly-phenylene-diamine (PPD) derivatives that produce specific oxidation products that bind with the dye couplers in the film layers to produce very specific colors of dyes, with density proportional to the amount of silver developed. Once the developed silver is bleached (usually back to a halide of some sort) and the halide fixed away, all that's left is the image formed by the dyes.
Xtol will give you an image, but it'll be three or four layers of B&W negative image, without a hint of color, because neither phenidone nor ascorbate produce the cocrrect oxidation products to bind to the dye couplers. Then your blix or bleach and fixer will remove the silver image, leaving you with blank film (just as would occur if you put black and while film through a C-41 process, because there are no dye couplers in the emulsion). You might be able to get a faint wrong-color image if you use a PPD-based developer, but few if any B&W developers use this developing agent because of its low activity, low contrast, and higher toxicity than metol, phenidone, or even hydroquinone.
I don't think EK has hundreds of any type of particular expert any more, and they certainly don't have hundreds of people working with photographic film.EK still has hundreds of chemists working there, right?
Hi David - it's a bit fateful, missing a few hours at school and you can never make up for the missed chemical class.Your responses are always exceptionally succinct, unambiguous, and always readily understandable by non chemists like me. - David Lyga
Color developers are generally poly-phenylene-diamine (PPD) ........[...........,]. ..,.You might be able to get a faint wrong-color image if you use a PPD-based developer, but few if any B&W developers use this developing agent because of its low activity, low contrast, and higher toxicity than metol, phenidone, or even hydroquinone.
Best wishes to you in Philadelphia , David !
combined with metol as a second agend it became very popular during the 20s/30s.
....right, I have it in mind! But a good time before there was a popular one : named Methol extra fine grain I can't find the formulation but I have it somewhereThere was a developer known as 777 that combined PPD, Glycin, and Metol, IIRC, and could be self-replenished indefinitely -- it was very popular with portraitists because of its tonal rendering and extremely fine grain (both greatly enhanced after extensive seasoning).
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