trendland
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The color developing agents CD-1, CD-2, CD-3, and CD-4 can all be used as substitutes for PPD in fine grain developers. CD-1 and CD-2 are chemically very similar to PPD. They are also cheaper than the other two. However, they also produce allergic reactions and cross sensitization. CD-3 and CD-4 are somewhat safer to use. Interestingly the color developing agents have also replaced developing agents that are no longer made such as Atomal.
Kodak's answer to the Sease formula was D-25. By lowering the pH of the developer development times were lengthened thereby the solvent action of the sulfite has more time to work. Same fine grain without the danger of PPD.
Yes good idea Gerald - to use CD1 or CD2 I have had the same idea some
times ago.
But looking to the chemical structure
CD1 and CD2 are very more complicate/complex than PPD.
May be that it works very simular - does
it contains PPD additional - this is not in my mind now - but yes it is within the
structure formular - you mentioned it above.
But then it is not origginaly - I would say
you can substitute it in many ways - with
the lost of the special effect.
So as D25 does.
with regards
