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Topic: Restoring color to faded Eastman film

John Schulien
Expert Film Handler

Posts: 206
From: Chicago, IL, USA
Registered: Nov 1999

posted 05-15-2003 12:25 AM

Ok, just because the USPTO issued a patent doesn't mean that the process works, but here's a fellow who claims to have invented a method of restoring the color to faded Eastman film.

U.S. Patent 6,537,737

Has anyone heard of this process, or heard of any studies as to whether it works?

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Ken Layton
Phenomenal Film Handler

Posts: 1452
From: Olympia, Wash. USA
Registered: Sep 1999

posted 05-15-2003 01:22 AM

I don't get it----how can you put the color back into a faded print? Once the dye has faded it's just plain gone. What happens when the film has tape splices in it? Does this process screw up the tape splices? What if the print has scratches, does it work with scratches? How would this process work with a print that has vinegar syndrome?

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Leo Enticknap
Film God

Posts: 7474
From: Loma Linda, CA
Registered: Jul 2000

posted 05-15-2003 02:30 AM

Most of the chemistry is beyond me, but to me this looks completely gippo!

Firstly, his rationale over the reduced contrast in black-and-white is inherently flawed. Quote:

quote:
With regard to black and white motion picture films, which include many of the great films of the past, a problem often encountered is a limited contrast range. Films intended to have a rich range of contrast, including jet-blacks, exhibit only an assortment of pallid grays. <edit> Black and white films made after 1950 on safety stock are also typically printed generations away from the original negative, as these original elements could sustain damage if subjected to repeated use.

OK, I accept that black-and-white elements which are several generations removed from the camera negative are flatter, less contrasty and have excess gamma relative to the generation before it.

quote:
Enhancement of black and white film in accordance with one form of the invention includes an expansion of the contrast range of the film, turning murky grays into deep blacks, bringing out textures in set and costume design, and revealing artistic lighting effects that were either muted or lost.

How far do you take this process? I mean, presumably you could heighten the contrast by this method too far and make it more contrasty than the original. And how can this chemical cocktail 'sharpen' individual grains of silver halide? I note that the patent application says that you should just fumigate your films with this brew over and over again until you like the look of it - doesn't sound very scientific to me!

But what really makes me suspicious about this is his assertion that this process will 'restore' colour and b/w film alike. B/w is essentially just silver halide, which is a very stable substance. The emlusion just doesn't change over time in the way that Eastmancolor did. Dye-coupler colour emulsions are a totally separate (and far more complex) set of chemicals, and the contention that the same treatment will have an identical effect on both just doesn't ring true for me.

BTW, I've posted this link on the AMIA list and will be very interested to see what the preservation experts have to say about it...

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Stan Gunn
Expert Film Handler

Posts: 176
From: Clematis, in the hills near Melbourne Australia
Registered: Aug 2000

posted 05-15-2003 02:32 AM

Fantastic, now we can restore colour that is not there and make B/W prints look like new with details that don't appear on the washed out 10th gen copy.

Were can I get it What does it cost? [Roll Eyes]

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John Anastasio
Master Film Handler

Posts: 325
From: Trenton, NJ, USA
Registered: Sep 2000

posted 05-15-2003 05:12 AM

The further removed a print is from the original negative, the MORE contrasty it gets. Negatives are intentionally shot flat, because the printing process always increases the contrast. As an example, make a photocopy of a picture....then copy the copy. See what happens? Contrast is increased by multiple generations, not decreased. Also, the active element in emulsion is only a silver halide in unexposed film. Once it's developed, it becomes stable, metallic silver and is no longer either a halide or sensitive to light.

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Leo Enticknap
Film God

Posts: 7474
From: Loma Linda, CA
Registered: Jul 2000

posted 05-15-2003 05:55 AM

...so what does he hope to achieve by winding the film over a light box after having casseroled it in chemicals?

By 'less contrast' I meant 'less visible detail which depends on accurate rendition of contrast', not a greater uniformity of emulsion density - sorry.

BTW, have you seen the drawing of his film fumigation machine? I gather that San Quentin don't use their gas chamber much anymore - I'm sure it could easily be adapted for the purpose! [Roll Eyes]

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Stephen Furley
Film God

Posts: 3059
From: Coulsdon, Croydon, England
Registered: May 2002

posted 05-15-2003 07:37 AM

"Additionally, the optical track, which had looked rather soft in focus and low in contrast, has sharpened considerably and deepened in its contrast range."

So the processs not only increases the optical density, but also sharpens the focus of the optical sound track. I would like to see (and hear) a demonstration of this process.

Ammonium Dichromate, or rather a mixture containing it, can be rendered relatively insoluable in water by exposure to ultra violet light, but he's not exposing the film to dichromat, just to 'vapors'.

I think exposure to glycerin would tend to soften the emulsion, would it? This might help to reduce minor scratches.

Calcium hydroxide is lime, and is very non-volitile. It would simply be left in vessel in which the mixture is heated.

I'm not sure what the effect of ammonium phosphate on film would be.

For this process to work, it would need to add optical density to the film image in proportion to that already there, like a positive mask added to a positive image. I can see no way that this process is going to do that. How it is going to do that to each of the three dye layers of colour film, to restore the optical density of each layer to the appropriate wavelengths of light to what it was before fading, is even harder to see.

I've got some very faded print film, some in was in the 16mm soundtrack scans which I posted a few months ago.

I challenge this person to make any noticeable improvment to those prints, using his process.

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Frank Angel
Film God

Posts: 5305
From: Brooklyn NY USA
Registered: Dec 1999

posted 05-15-2003 10:54 AM

I once heard that the Russians were experimenting with a process that identified the molecular differences between the three color dyes. If understood it correctly, although the color fades, the molecule that holds the color remains. Using a radio active wash that only clings to specific color molecules, they can radioactively mark where each color used to be. How they then apply color back to the markers is lost in my faded memory, as is the source of this (perhaps an article in Big Reel -- not at all sure). Also not sure if they concluded that it worked.

Has anyone else heard of this?

Frank

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John Pytlak
Film God

Posts: 9987
From: Rochester, NY 14650-1922
Registered: Jan 2000

posted 05-15-2003 11:23 AM

Modern color films form the image dyes when a dye-forming "coupler" reacts with oxidized color developer released when the exposed silver halide grains are developed:

http://www.kodak.com/US/en/motion/support/processing/sequence.shtml

http://www.kodak.com/US/en/motion/support/processing/h249/h2409_011.shtml#130997

Dye-forming coupler technology has evolved over the years, and many different couplers have been used in various products. Likewise, several different color developers have been used (e.g., CD-2, CD-3, CD-4). So the dyes are not all alike, and don't have the same chemical structure. There are literally hundreds of different dyes.

Color dyes fade at various rates, and fading is affected by a variety of factors. For example, some dyes required "stabilization" with formaldehyde or similar chemicals to "tie up" unused coupler. If the processing did not follow Kodak specifications, residual processing chemicals (e.g., thiosulfate) or incorrect emulsion pH would harm dye stability. Acids formed by "vinegar syndrome" or hydrolysis of magnetic striping accelerated fading of some dyes. The effects of improper storage conditions are well known:

http://www.kodak.com/US/en/motion/support/technical/storage1.shtml

http://www.rit.edu/~661www1/sub_pages/8contents.htm

http://www.rit.edu/~661www1/sub_pages/dwnloadcounter.html

http://www.kodak.com/US/en/motion/support/technical/molecular.shtml

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Ken Layton
Phenomenal Film Handler

Posts: 1452
From: Olympia, Wash. USA
Registered: Sep 1999

posted 05-15-2003 05:39 PM

If this process is good, then a major film manufacturer should buy the patent. They'd have people lined up to get their films restored.

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Steve Kraus
Film God

Posts: 4094
From: Chicago, IL, USA
Registered: May 2000

posted 05-17-2003 02:19 PM

I can understand the general concept that it could be possible to chemically "amplify" an image, especially the silver image in B&W film but the notion that a simple process would work just as well on color defies comprehension. In theory it seems possible but as John points out there are lots of different chemistries involved. Hypothetically perhaps one could design a process whereby certain dye chemicals are used to trigger the formation of new dyes (which are in the restorative solution). Maybe one bath each for Y C and M with the amount of time in each or the temperature determining whether each extant dye molecule gets augmented by how much new dye. Careful measurement ahead of time to determine the percentage of fading (one looks for an area known to be black) would determine how much restoration is needed for each color.

So in general, it could be done. But I doubt that this is it.

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Frank Angel
Film God

Posts: 5305
From: Brooklyn NY USA
Registered: Dec 1999

posted 05-17-2003 05:45 PM

Besides, it seems a little ludicrous that an industry which routinely BANDSAWS prints, would be concerned in preserving them. But, one would ask, what about the studio's Classic Departments? Hey, they won't spend any money to strike new prints when they have existing negatives; what makes anyone think they would spend money to restore faded prints?

Then there are the collector prints; to my knowledge, no studio has ever spent any money to acquire a good print from a seller. For example, once when I was booking LAWRENCE (before the restoration), I mentioned to the head of Columbia Classics that, ironically, there was a collector offering an IBTech print for a measily $1000. Her comment was, she would give up her first born to have an IBTech print of that title in her library. I asked why wouldn't CC just purchase it -- it would be cheaper than striking a new print and it certainly would look better. She sighed and said the classics department was more of a "lip service" to film heritage that the studios feel they need to promote. In reality they are not willing to put a penny more into them than they have to. She also explained that there were many current titles that she knew would have indefinate life in the art house circuit, but she couldn't get the studio to save a few prints of these titles for her when they were distroying inventory. The biggest issue was the costs of storage.

So who would be footing the bill for R&D and then paying for the recoloring process for old prints when the studios aren't even interested in storing them?! Wouldn't it be ironic if at one point a print is "colorized" only then to be bandsawed a year or two later.

Frank

[ 05-18-2003, 07:35 AM: Message edited by: Frank Angel ]

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