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Copying color negatives with camera

Started Oct 13, 2014 | Discussions thread
justinwonnacott Senior Member • Posts: 1,279
Re: Copying color negatives with camera

Hi;

This link may be useful to you regarding the theory of what you are trying to do. http://www.hpl.hp.com/techreports/97/HPL-97-16R1.pdf

Colour masks vary according to brand and emulsion type.

The mask is there to compensate for deficiences in the colour dyes in the film (the cyan component being the worst . . . The mask is formed in proportion to the "developed" colour dyes in the emulsion layers - the more image there is the less mask and where the - where is no image  it is all mask. The curves are NOT parallel making correction hard.

If Slide film is processed as a negative the negative image is a nightmare to print because of the absence of the corrective mask. Bad blacks (brwns usually" and crossed characteristic curves making accurate reproduction almost impossible. Photoshop would make this easier , but without a map (lookup table) and some way to interpret it you are working blind.

MAYBE...It might be useful to shoot a grayscale on the negative stock in the light the film was designed for - this would represent a known colour when printed correctly, and scanner software could be used to determine the rgb figures for each step of the grayscale target. Knowing the actual numbers might make it possible to kludge a corrective curve that works.

on the other hand colour negative film fades just as badly and as quickly as colour prints......

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