Quote Originally Posted by wildbillbugman View Post
Hi Kirk,
I wonder,do you have any sugestions as to other dyes, with published structures , that could be used as green and red sensitizers.
Well, I have no first hand experience, but I have a nice book from the 1940s on infrared photography. It has a really nice section on the history of sensitizing dyes.

It says that Erythrosine was discovered in 1884 by Eder. And that there was a renaissance in dye sensitization in 1904, and that Ethyl Red was one of the first dyes identified at that time. Cole Parmer lists Ethyl Red at about $55/25 grams.

It then says that shortly after ethyl red, came Orthochrome T, Pinaverdol, and Pinachrome - all isocyanine analogues, as was ethyl red.

Then Pinacyanol was discovered, and it was the most important sensitizer for red, and it was used in all panchromatic emulsions up into the 1930s. It was a family of compounds, with one variety marketed as Sensitol Red by Ilford for this purpose in the 1920s. Sigma-Aldrich lists Pinacyanol iodide at $90/gram.

The book says Pinacyanol gave good sensitivity in the red and on down into the green, but that it was also used with Orthochrome T, Pinaverdol, or Pinachrome for increased green sensitivity. Pinaverdol was known as Sensitol Green, to go with Pinacyanol's Sensitol Red name.

Also mentioned, Pinaflavol as a green sensitizer form after the First Great War.

And Kryptocyanine and Neocyanine are discussed as popular infrared dyes from the 1930s.