Did I do something wrong?

dslater said:

Staining developers are usually use either Pyrogallol or Pyrocatechin as the primary developing agent - PMK Pyro and Pyorcat-HD are 2 examples. As they develop the image, they also stain the gelatin a yellowish or brownish color - the amount of stain is proportional to the density. A search for Pyro or Pyrocat on this site will bring up many threads. You also can go to www.unblinkingeye.com where there are many of articles about staining developers.

Dan

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Pyrogallol or catechol are primary in quantity but not necessarilly in function. Hydroquinone will stain as well as catechol in the same formula, but a different color. Add more sulfite to any of the catechol series and you will have little or no stain. HC110 used catechol instead of hydroquinone once upon a time. The combination of the development products of a low sulfite developer and one of the hydroybenzene makes the dye that stains the image. Another result that is of consequence is the tanning of the gelatin in proportional to the image, that is said to give certain edge effects that improve apparent sharpness.

Sorry about the lecture. I just can't help myself. The point I started out to make was that in any non-staining PQ or MQ developer, which might have the same proportions of the two agents as a staining developer, we would usually refer to the Metol or Phenidone as primary. It's not as important as I seem to have made it, but simply a matter of interest.

I even goofed on hydroXybenzene. Catechol and hydroquinone are both dihydroxybenxenes while pyrogallol is a trihydroxybenzene.

The newspaper reported "We said that Officer X is a defective in the police force. We should have said Officer X is a detective in the police farce."

gainer said:

Sorry about the lecture. I just can't help myself. The point I started out to make was that in any non-staining PQ or MQ developer, which might have the same proportions of the two agents as a staining developer, we would usually refer to the Metol or Phenidone as primary. It's not as important as I seem to have made it, but simply a matter of interest.

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Go ahead and lecture away - I'm always interested in more information on this stuff.

jgcull said:

What is a staining developer?

Thanks for all of your replies!

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Some people have even been known to use coffee mixed with a few common ingredients like washing soda as a staining developer. Do a search on folgernol and caffenol to find more on this.