Re: Orange Mask in Color Neg film (digest 1541)

[P3D Bob Howard <bobh@xxxxxxxxxxxxxxxxxxxx>]

RE: Dr.T says Greg E. asks 'can you filter out the orange colour during
the taking?"

I missed the original so think Greg is talking about copying film images
etc. from a color negative or ?. (If he is getting 'orange' from a wrong
Kelvin light source that is corrected by filtering.) The orange mask in
color neg is of course also filtered out in printing to get "white" or
18% gray. It is put in the film to help the three layers have a purer
color separation better than the dyes used for the final printing allow.
(Since all layers are blue senstitive you can say it is getting the blue
out)
The very first color negative film from Agfa had no mask and was very
pretty to view as had the pure complementary colors. Later they all
added the orange mask. 
Because the color paper is designed for the mask, if you print for
example Ilford XP film to color paper you have to insert an orange mask
in the form of developed but no image color neg film piece in the path
in order to get a good black and white. Even the one-hour guy has to do
the equivalent in his machine and often used a piece of film. BobH


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