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Author Topic: Green scratches on red film??? Greg Mueller Phenomenal Film Handler Posts: 1687 From: Port Gamble, WA Registered: Jun 99 posted 10-20-2003 10:03 AM                        I have an old print from the 50s that has turned red. When I first got Film Guard I tried it on that film as a test. The film was quite dirty and had what I thought was black scratches. As the Film Guard worked I began to see that the scratches where not black but green. Apparently the green scratches had filled with dirt and the Film Guard cleaned the dirt out showing the true green color. So if the aging of the Eastman film makes it lose it's blues and greens leaving only the red, how is it there is still green in the scratches?.....John?  |  IP: Logged Sam Hunter Jedi Master Film Handler Posts: 779 From: West Monroe, LA, USA Registered: Jan 2002 posted 10-20-2003 10:08 AM                     Corrosion Thats a good question though.  |  IP: Logged John Pytlak Film God Posts: 9987 From: Rochester, NY 14650-1922 Registered: Jan 2000 posted 10-20-2003 10:20 AM                        Evidently, the "dirt" filling the scratches in that old film was oil and miscellaneous debris. When dyes fade due to improper storage, you usually lose only a percentage of the dye's density; most of the dye remains. Here are some excellent papers on the chemistry of dye fading: http://aic.stanford.edu/jaic/articles/jaic31-02-005.html http://unesdoc.unesco.org/images/0005/000586/058641e.pdf http://www.rit.edu/~661www1/sub_pages/8contents.htm  |  IP: Logged Dominic Case Expert Film Handler Posts: 131 From: Sydney NSW Australia Registered: Aug 2003 posted 10-20-2003 06:39 PM                       The film image consists of yellow, magenta and cyan dyes not red, green and blue. Magenta is the top layer in print film, then cyan, with yellow at the bottom. When film gets scratched and the top layer is removed, you are left with green (yellow + cyan, missing the magenta). Even if just the protective supercoat is removed, and oil gets into the emulsion, it will rapidly cause that magenta layer to fade. So you get green scratches again. As John suggests, dirt filling the scratches made them appear black before cleaning. Now, the rest of the image appears red because the cyan dye layer has faded most of all (due to time, temperature, humidity, etc) over the years. From the era of that print, cyan was the least stable dye. But there's probably still a proportion of cyan there - enough to make the scratches appear green by contrast with the rest of the image.  |  IP: Logged William Hooper Phenomenal Film Handler Posts: 1879 From: Mobile, AL USA Registered: Jun 99 posted 10-21-2003 12:06 AM                        I ran a cartoon that had turned green - all over, the color change was in the base. Onscreen, white areas in the picture were green, etc. Pink is better.  |  IP: Logged John Pytlak Film God Posts: 9987 From: Rochester, NY 14650-1922 Registered: Jan 2000 posted 10-21-2003 05:46 AM                        quote: I ran a cartoon that had turned green - all over, the color change was in the base. Onscreen, white areas in the picture were green, etc. Pink is better. One possibility: Until the late 1980's, the magenta dyes used in color print films required formaldehyde in the final rinse to "stabilize" the unused coupler and prevent reaction with the magenta dye that had just been formed. If the formaldehyde was not at the proper concentration, prints would quickly turn green.  |  IP: Logged

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