Quote Originally Posted by VesaL View Post
Precisely, i Have bottle of Rollei Black Magic variable contrast emulsion sitting on my freezer. The problem is that one can coat a glass plate with this variable liquid emulsion, but I would need a red sensitization into it also, that i could could use it as a viable emulsion for"Autochrome" plate. straight from the bottle, I can render the blue & green but not the red. I could sensitize the emulsion using Methyl violet (ethyl I cannot obtain) but like PE said, this would probably mess the blue & green record, IDK.
Forgive me my ignorance, but why would you want/need to do this?
(This is not criticism but me wanting to learn & understand this)

BTW: if I remember correctly, in the How To document I mentioned before (see link above) there is some text about mixing emulsions & influencing contrast and gradation, If my memory serves me well.