Film-Tech Forum ARCHIVE: Eastmancolor fading

This is topic Eastmancolor fading in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Brad Miller (Member # 2) on 06-05-2002, 01:38 PM:

Perhaps John and some of the archivists out there could answer this one. I was looking at an older print from the late 70s on Eastmancolor that is just starting to fade. The whites were still white, but the blacks were turning red. The movie was flat and was being projected with proper 1.85 lenses and plates. However I noticed that during the dark scenes the top and bottom edges of the picture were still black. Upon racking the framing control a bit, I noticed that the area that was not hit by a xenon/carbon arc lamp still had good color and true blacks, yet the area of the image that was not masked off had fading. (It appeared whoever ran this print used 2:1 plates.)

So are high intensity arc lamps to blame for speeding up the color fading this much on these older films? I know projecting through high intensity light sources can fade a film, but I've never seen anything like this. All other Eastmancolor prints I've seen had equal fading throughout the print (from frameline to frameline).

Posted by John Pytlak (Member # 331) on 06-05-2002, 02:06 PM:

The chemical reactions that cause dye fading occur both in the dark, and when exposed to light. But "Dark Keeping" and "Light Fading" may be different mechanisms, and affect the dyes differently. Dark keeping can be greatly extended by storing the film in cool and dry conditions, as specified by SMPTE Recommended Practice RP131. Light fading can be minimized by reducing the amount of ultraviolet energy from the lamp (e.g., the Century UVIR filter). Although it usually takes thousands of projections at very high power levels to fade the dyes noticeably (special venue theme parks run loops of film tens of thousands of passes), it would not surprise me if the added radiant energy of projection also added to the effect of improper storage on "dark keeping".

In addition to storage temperature and humidity, other factors include the processing (washing the film to "archival" levels of retained thiosulfate, maintaining proper pH, proper stabilization), and reducing or venting trapped acid vapors in enclosed storage.

------------------
John P. Pytlak, Senior Technical Specialist
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Posted by Jeff Taylor (Member # 443) on 06-05-2002, 02:45 PM:

Brad: I think I would vote for the heat of the lamp in the unmasked area being the culprit moreso than the intensity of the light, and if I read John P's comments correctly I think that's what he was implying. Still, they must have had a LONG run of that title with the wrong masking to produce that result. I know I've never seen that.

Posted by John Pytlak (Member # 331) on 06-05-2002, 02:58 PM:

On the print film samples supplied by a theme park that had been run tens of thousands of times, the light-related fading that occured caused the shadow areas to go slightly green, with a slight yellow stain in the highlights. The area of the image "protected" by the aperture showed no fading. Ultraviolet energy is the usual "culprit" in this type of magenta dye fading. Heat and acidity are the usual culprits for the cyan dye.

Posted by Leo Enticknap (Member # 534) on 06-05-2002, 03:40 PM:

All the faded pre-print elements I've handled (i.e. camera negs, fine grain positives, dupe negs and reversal intermediates) are faded evenly - I've never come across anything with the differential fading Brad describes. I guess this would support John P's theory of the culprint being intense, localised heat in the frame area as distinct from light.

Posted by Frank Angel (Member # 248) on 06-06-2002, 10:31 PM:

On one of the news groups I came across a collector fellow who insisted that he would not run any of his prints without an ultraviolet filter in the lamphouse. He was adament about the fading properties of ultraviolet light exposure on the emulsion dyes and he said that he could easily show the effect in a lab with the proper testing equipment. I guess I will go out to find an ultraviolet filter somewhere. Edmund Scientific perhaps?

All you have to do is walk past a store window that's has a poster that;s been in it a little too long. It will look just like a faded print. I have a beautiful souvenir book from THE GREATEST STORY EVER TOLD (the book was better than the film) that I've kept on a table in the living room. At one point my lady put one of her books on top of it but covering only 2/3rd of it. Much to my dismay, when I took away the top book, I found the souvenir book had faded where it wasn't covered.