Czech Autochromes

[PaulRicciardi]

Thanks for the post, some really good work in those galleries.
The early colour work is very beautiful.

[Bill_1856]

I wonder what the "ISO" would have been for Autochrome plates?

[Ernest Purdum]

Wilhelm, I haven't found it yet, but I found "sixty times as slow as the normal negative emulsion of that period". I'll keep looking. That low sensitivity emphasizes the achievements of the Autochrome users. Underwater? Amazing.

[Nathan Potter]

Never really knew how these autochromes were made but I see the process was pretty clever. The notion of filling the voids between the dyed starch grains with lampblack serves to enhance the suttle color aspect of an autochrome by somehow decreasing the contrast of the image peripherally around each grain. Perhaps this is sort of analogous to a first generation contrast film masking process in color printing.

The photomicrographs of Karel Smirous in autochrome are particularly fascinating. They look like geologic thin sections executed under polarized light microscopy.

Many thanks Struan

Nate Potter, Austin TX.

[aduncanson]

I thought that the lamp black was necessary to preserve the intensity of the color, which otherwise would be overwhelmed by white light coming through the spaces between the starch grains.

This technology is very cool. I wish somebody made materials for a similar process today, replacing the randomly arranged dyed starch grains with tiny plastic filter elements on a clear substrate backed with a B&W reversal emulsion.