Donald Qualls
Subscriber
I've seen a couple references recently to Talbot's positive/negative process. I'd never realized previously that it could be done in camera -- apparently with exposures of mere seconds, in the 1840s! -- once he hit on developing out and using silver bromide instead of silver chloride.
Who's done the Talbot P/N Calotype? I didn't catch it in the video -- was it ferrous sulfate for developer?
Is it possible to add other salts to the impregnated paper, as is done with collodion, to further increase speed and broaden spectral sensitivity (collodion gets into green with some combinations)?
Are there good online references for this process?
Who's done the Talbot P/N Calotype? I didn't catch it in the video -- was it ferrous sulfate for developer?
Is it possible to add other salts to the impregnated paper, as is done with collodion, to further increase speed and broaden spectral sensitivity (collodion gets into green with some combinations)?
Are there good online references for this process?