Steve Hamley
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Don't want to hijack the thread, but I have no idea what acetic_sodium sulfite is. Do you mean Acetic Acid as one possibility and Sodium Sulfite as another? What is used to bleach a pyro stain?
I have a similar neg with a pyro streak (Pyrocat) and have been wondering what I can use to bleach out the stain. Don't want to hijack the thread, but I have no idea what acetic_sodium sulfite is. Do you mean Acetic Acid as one possibility and Sodium Sulfite as another? What is used to bleach a pyro stain?
Thanks Steve, that clears it up.
Ian, how would you recommend bleaching a pyrocatechin stain? I really want to save the aforementioned negative.
In all fairness to PMK, at this point we really don't understand what's going on, or if the issue would occur with other developers, commercial or not. ??Cheers, Steve
I think this unfortunate cicumstance points out the problem of using a developer that has not been thoroughly tested. Just because many people have used this developer does not mean that all its kinks have been discovered. Commercial developers have been exhaustively tested under various conditions. Often it is the case that more man-hours are spent in testing than in the initial development of a product.
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On the contrary we do know what is going on. All dyes are subject to fading, some more rapidly than others. From the OP's sad experience he has shown that the stain image produced by PMK is not stable toward light. This problem will be the same for all stain developers whether they use pyrogallol or catechol. Developers that produce only a silver image will not have this problem. People need to be aware of this problem and protect their negatives from strong light.
In fact this thread is the first I've really heard of the issue. Intuitively we know dyes are not infinitely stable, but since we always read the stain is "permanent", I guess most people assume it is permanent enough so that the printing properties of the negative will not change over its reasonable "print life" (I mean, does a negative realistically need to outlast its printer?). This thread, however, points to stained negatives potentially having significantly lower stain stability than I had ever considered. A little scary.
I'm wondering why, for example, a guy like Alan Ross hasn't noticed this when printing any of Adams's older stained negatives. Or maybe he has and hasn't written about it. Or maybe it's that Adams's negatives are so carefully stored.
Anyhow, very interesting discussion here. I rarely use staining developers anymore, but I'm still intrigued by this.
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