Greetings,

I often hear folks referring favorably to films as being "silver rich," or "thick emulsion." These are supposed to be desirable qualities of films from yesteryear, especially when used with Pyro developers. I would like to hear from folks that have used these "magical" films from yesteryear, as well as those versed in chemistry, because I'm having a hard time believing there's something "special" about them.

I heard folks claim that silver rich films stain better in pyro. Pyro stains proteins; it was used in the 1800's as a tanning agent, as it would react with the protein in animal hides. So how does it stain better with silver? I don't believe it does. I believe it reacts with the proteins in the gelatin that forms the emulsion and has nothing to do with silver content. Can any chemists confirm this?

Thick emulsion, would certainly seem to have a greater affect on stain, as there would be more protein, but OTOH is thick emulsion better? It would seem that the thicker the emulsion the less sharp an image would be due to diffraction. This would be especially true of negatives that were destined for the enlarger.

Super XX may have been a "special" film, though I have never used it. From knowledgeable people that have used it, I understand that what made XX unique, was it's linear response to red, green and blue light; not the fact that it may have been silver rich, or a thick emulsion. I believe many of the films made today are quite good, perhaps even better that yesteryears films, just different. Is there anything to silver rich, or thick emulsion films being truly better, or is it myth?

Thanks!

Regards, Pete