Why are only silver based films used?

It's my understanding (according to an old set of Funk & Wagnall's encyclopedias) that non-silver based emulsions have been developed over the years. Why have none of these become a serious competitor to silver halide emulsions?

Also, I recall some chatter a while back about a fine grained, super fast (~25,000 iso) b/w slide film with a thermal process (not sure if silver was involved) that Kodak was testing. Is there still any hope for it to be released?

Silver was involved with the 25,000 speed film, I assure you.

No other method than silver halide in gelatin allows spectral sensitization and high speed, not to mention color.

There you have it!

Many have tried for years to get other systems to work, and they simply do not. I myself worked on a light sensitive system using copper. It failed to make the grade for the reasons stated.

PE

From what I've read (just putting it in simpler terms) silver just gave/gives the best image.

You can make a light sensitive emulsion out of iron compounds. It works, I've seen it done, but IMO, does not give a very good image.

It's entirely possible you could make an emulsion out of gold, too, but it would be pretty pricey.

We used to joke that we had solved the silver problem. We went to the director of research and told him that we could replace silver with platinum.

PE

I direct you to the execellent textbook by Khosar on alternative processes.

PE

Photo Engineer said:

We used to joke that we had solved the silver problem. We went to the director of research and told him that we could replace silver with platinum.

PE

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When I first read this thread I was wondering if the reason that silver became the basis was that it was the most affordable choice?

I know that in electronics silver/lead solder is the standard - because who but the DOD can afford to use gold!

Theophile Dimitrios Dektolopoulos, the famous Greek researcher (known for his contribution to the photographic industry with the invention of Dektol) was working on the revolutionary olive-oil based photosensitive compounds when, tragically, death met him in his house while he was trying to fix a broken spring under his bed. His research wasn't continued, for the notes he kept were all written in an ancient dialect that has never been translated as it was only spoken by an obscure tribe or Greek Bushmen of the South, where is now the new city of Herakleion, Creta (some say that Aristotelis Grammatikakis is the only descendant of this tribe, although he doesn't agree with the specific theory).

If your parents don't have any children, you probably won't either.