Marco , I spent the last night diving in the internet and I found a russian site which posted 1940 Dye Technologies of Kodak book. I saw there many chemicals for example for green have extremelly different sensitometry. And I found ph degrees change the curve also. But When I look to the patents , for two color process of 1922 to 1927 , used salt of sulfonic acids. This information narrows the search.

I think I need the first book of Kodak written at 1920 , not 1940. I believe this will make the search field narrower. I wrote to Eastman House and waiting an answer also. Its too difficult for me to read book from screen and I think I will order a print and look for the clues.

This video was a eye opener for me and Thank you very much.

It is quite interesting how much research done on this field and the wide palette of chemicals even 90 years ago.

So I need answers to my specific questions , try and hit is impossible , its like finding the technology of Egypt Pyramids building technology with experiment.