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Topic: Red film tint
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John Whittle
Jedi Master Film Handler
Posts: 791
From: Northridge, CA USA
Registered: Jun 2003
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posted June 07, 2009 09:06 AM
Jon Check throught the forum archive, this is a lot of information on this. Basically a filter will not help. If it's just a little red, you can add a filter (in this case cyan not green) but it will tint the highlights of the image. Working electronically in telecine you can do a bit more since you can set midtones, highlights and shadows on their own.
The other technique is to do silver seperations and then print them back with different exposures that will hold white and black, but that's very expesnive and as far as I know only done on 35mm.
As for stopping it, that's hard to do. Some think storing the film at zero degrees F will slow down the action. What is happening is that the chemical elements that make up the cyan in the color in the image aren't leaving, they're just turning clear thus reducing the density of the original and turning it red.
In Eastman color negative materials from the 50s and 60s, the problem is with the yellow layer going causing a printing imbalance toward the blue in the print. There again, silver seperations if made originally can be used to make a new dupe negative with proper color balance--at considerable expense.
This is one of the "little" problems with film such as nitrate base decomp, safety film vinegar syndrome and dye fading.
John
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