Film-Tech Forum ARCHIVE: Non-digital restoration of pink prints

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Posted by Peter Berrett (Member # 672) on 07-27-2006, 10:08 PM:

Hi all

Has anyone, including Kodak, ever developed a technique or mechanism for restoring old prints that have gone pink? There was a thread recently which discussed a digital restoration of a faded print and the comment was made that even though the print was severely faded there was still a lot of color information left in the print.

Digital restoration aside, perhaps it would be possible to restore an old print by reinjecting the dyes that have faded? This could be achieved by a camera scanning the picture to identify the faded colors, followed by a small laser to micrscopically drill tiny holes in specific spots on the film into which the dye could be injected and then finally followed by some sort of sealing process. Sort of like printing on film.

Alternatively if a laser was unfeasible the dyes could be imprinted on the top layer of the film and then sealed over with several new layers.

Those old pink prints might still have some value!

Regards Peter

Posted by Carl Martin (Member # 1146) on 07-28-2006, 04:01 AM:

there was talk a few years ago about some process of soaking film in something or other that would reassert dyes that had faded. i believe talk was all it was.

your idea of "tattooing" the film seems incredibly impractical and probably impossible. it is possible to restore the color by reprinting, and the results would probably be better and cheaper. not as good as the original, of course.

i wish this were still done instead of the digital means that seem to be employed most often now. for example, the recent re-release of army of shadows just didn't look right to me, even though the restoration was supervised by the dp. (great movie though.)

Posted by Jim Bedford (Member # 4) on 07-28-2006, 04:26 PM:

Why would anyone want to spend the money necessary to "restore" color and balance to beat and fading Eastman acetate prints? I have some fading prints but would be unwilling to spend very much on anything that's going to vent off as acetic acid gas in the next few years. What does make sense is using original negs, reprinting a bunch of desirable titles in LPP on poly stock, making them available to theatres and seeing if there is a market for them.

Posted by Frank Angel (Member # 248) on 07-28-2006, 05:57 PM:

Obviously this is a question asked by people who have collector's prints. If any exhibitor really thought he could make a respectible profit by playing a particular older title, one of which the studio doesn't have a decent print (if the studio doesn't have a decent print, it is usually because they have already determined that there is not a large enough market to strike new prints), then he can always put up the money to have a print struck. I know a number of outfits who travel playing their own compositions along with silent movies. They paid the studios to strike prints for their own use. So if an exhibitor really thought he could make $$$ from a title, there is an easier way than to try to accomplish what no one, not Kodak, not Fugi, have accomplished with all the modern R&D and film chemistry at their disposal.

But I know your angst -- I have many prints that are all magenta (a color, btw, that I used to like....not so much any more). I have toyed with the idea of experimenting with video projection. When I was at the 3D World Expo two years ago, Jeff Joseph ran a 3D print in which the only existing Left Eye print was faded, while the Right Eye print had good color. I was very surprised at the result. Even though one eye was looking at a very faded image, the brain seemed to ignore that bad color and rely on the good color that the other eye had access to. The picture looked much more like normal color than like faded purple. So, given that experience, I extrapolated a hypothesis:

Suppose you could get a DVD that has not been time-compressed in any fashion, and you had a faded print that was fully intact, i.e., no missing frames. Then let's say you would run both in synchronism and project each, the 35mm projector and the video projector, aligned perfectly on the screen, i.e., the images are superimposed on top of each other. My theory is that the color from the video and the high resolution of the faded print will blend together and the brain will combine the best elements of both, producing an image that looks very much like the high resolution of 35mm film, but with the balanced color of the DVD video.

Of course this is just a theory and even if it worked, it's execution would be absurdly complex and impractical. It would be fun to try though.

Posted by Peter Berrett (Member # 672) on 07-28-2006, 08:22 PM:

There is a need for such a process.

First there are many non-feature prints out there that are fading eg - home movies, that would be too expensive to copy. If Kodak or someone else could develop a laser guided film restoration (Sort of like Star Wars for film) method these prints could be brought back to life from the dead.

This may sound unbelieveable but then again every time I look at a printer I am amazed at how it can print a color page in a matter of seconds. If it can be done on paper why not on film?

Regards Peter

Posted by Carl Martin (Member # 1146) on 07-29-2006, 02:27 AM:

if it's too expensive to make a copy, then it would be far far too expensive to implement your method, which is analogous to making a copy, but with more alignment issues, and dependence on a unique technology that doesn't even exist.

Posted by Peter Berrett (Member # 672) on 07-29-2006, 04:01 AM:

Actually I just found something quite interesting...

The following comes from the following thread

quote:

KODAK LIGHTNING LASER RECORDERS

The Lightning recorder's technology is unique in that it uses red, green and blue lasers to expose negative film. The three lasers write directly to each color layer of the intermediate stock. This combination produces images of unparalleled sharpness and color saturation. The system's 10 bit (per color per pixel) log space retains all the film's enormous density range, while the lasers' extremely wide dynamic range ensures that the quality of the new negative is absolutely optimised
Kodak's laser recorder polygon has 16 facets and spins at 6120 revolutions per minute (rpm). The imaging lens is a high-performance, color-corrected f/theta lens which was custom designed for the recorder. The digital datapath of the Lightning laser recorder also includes color matrix and aperture correction boards. The color matrix is used to help eliminate color crosstalk on the negative. The aperture correction board applies a compensating correction for the combined optical losses of the film recorder ensuring that the full detail and grain structure of the film is preserved.
It is extremely important that the grain content in the recorded shot matches exactly that of the original film, so that when an added effect is edited into the finished sequence there is no discernible change in grain, a telltale sign of an added effects shot. Cinesite outputs to 5242 intermediate stock, which is virtually grainless (ASA 3) and has the ability to record the grain pattern from faster stocks so that the digital transformation is unnoticeable in the final edit. The lasers that the Kodak system uses are more intense than CRT's and are able to record out the full dynamic range of any other scanned original negative stock. At Cinesite the lasers are calibrated to give a maximum dynamic range of 2.046 density units to match the capability of the 5242 stock. When used with the Lightning film scanner, the Lightning laser recorder's output is nearly impossible to distinguish from the camera original

If these lasers can, with such precision, expose negative film, then likewise they could be used for the purpose I have outlined.

Whether they would drill holes I don't know but maybe a new thin layer of film could be laid onto the new film, the lasers expose this to add the extra colors and then some sort of sealing process could be added?

It seems to me that technologically it is possible - it is just a question of whether anyone has ever tried.

Regards Peter

Posted by Leo Enticknap (Member # 534) on 07-29-2006, 07:15 AM:

It's more a question of whether it would be economically viable than technically possible: my gut feeling is that it wouldn't.

Having a laser-out interneg made using a machine like this costs, at a bare minimum, around £250 per minute of footage, not including stock (for example, see this lab's price list). Even if it could be adapted to rejuvenate faded dyes, the cost is likely to be so large that you could have a new print struck (colour corrected using filtered light on a Bell & Howell 'C' printer, if necesssary) for a fraction of the price.

As others have pointed out, there would be no market for such a system as far as preservation is concerned. At present, photochemical methods (either filtered light printing to a dupe interneg or f/g pos, or, if you have a higher budget, making seps and a recombined interneg) are still a lot cheaper than 2k or 4k digital if the only problem is dye fading, though I don't imagine that being the case forever.

The reason this technology is so expensive is that the machines have a seven-figure price tag and run very slowly - around 30 seconds to scan a frame at 4k, and around 2 minutes to burn one. So, scanning or burning a feature takes days and sometimes weeks, which is why the cost of doing it per frame is so high. That's also why we don't have directly burnt release prints, but rather a lasered interneg which is then used to strike release prints the normal way. If burners which are cheap enough and fast enough to ever make it viable to burn an inventory of release prints directly ever come on the market, the likely print quality could be fantastic.

Posted by Frank Angel (Member # 248) on 07-29-2006, 08:01 AM:

quote: Peter Berrett
First there are many non-feature prints out there that are fading eg - home movies, that would be too expensive to copy.

Actually, while there may be many non-feature shorts out there on both 35mm and 16mm film that might be faded, the majority of home movies were shot on 8mm Kodachrome which is a color reversal stock and which has little or no color fading issues. I have reels and reels Kodachrome color 8mm home movies that my grandfather took as far back as 1939 and the color is pristine. Luckily for us the color dyes in reversal color didn't fade because if they did, those films would be lost forever being that there is no negative; each one is the only copy.

I am also happy to report that not a single foot of the thousands of feet shot has turned vinegar. What it is about thr acetate base that was slit for 8mm home use that has prevented it from going acid? It is a mystery and I have never heard an explanation for it. Our Kodachrome reels were never kept in any climate control at all -- they were just stored in a big footlocker in the basement which got very cold in the winter and very hot in the summer....go figure.

Posted by Leo Enticknap (Member # 534) on 07-29-2006, 11:39 AM:

Yup, we've got a lot to thank Leopold Mannes and Leopold Godowsky for. Apart from the short lived (1935-38) Kodachrome I, which fades pretty badly, the stuff is virtually bulletproof as far as fading is concerned. The same can't be said of Ektachrome and other reversal home movie/TV news reversal stocks which started to be used in the '60s, though.

Where the cost of photochemical duping for preservation is beyond what we can afford, there's also the option of telecine transfer and then rebalancing the colour in the computer (Premiere, Final Cut Pro and Avid Express can all do this). The big drawback is that the end result is only video, and so it's not a preservation option: but for TV quality access to the content without the pink, it works.

Posted by Peter Brown (Member # 3272) on 07-29-2006, 11:50 AM:

Do you mean Leopold Godowsky the concert pianist and composer of some of the technically hardest piano music out there?

Posted by Leo Enticknap (Member # 534) on 07-29-2006, 04:12 PM:

Kodachrome was co-invented by his son, who was also a professional musician (and amateur photographic chemist). The whole story can be found in Alan Kattelle, Home Movies: The Story of an American Industry, 1897-1979 (Nashua, NH, Transition Publishing: 2000), pp. 183-187.

Posted by Tim Reed (Member # 137) on 07-30-2006, 01:47 AM:

Leo, you're good! And, Peter, keep thinking, brother! That's how progress and fortunes are made! Restoring those faded layers is a swell idea. [thumbsup]

I know that faded film can be duped/reprinted, and the color balance adjusted using (help me, guys... additive or subtractive to fix faded cyan) printing lights.

Posted by Charles Greenlee (Member # 3856) on 07-30-2006, 03:13 AM:

Can't the film be transferred optically though filters to strike a 3 strip technicolor master. Thay way, you can tweak the component colors seperatly, possibly unsing exposure times, and then recombine them to a final print. Say your cyan is weak. You dupe it over to a technicolor master, and simply expose the cyan print a little longer, cause it to be better saturated in the final print. Yes, this requires your to make 4 prints or more in case of error(3 for the technicolor master, and 1 for the final print), but you may possibly bring back the color, without computer assist, or more expensive means.

Posted by Leo Enticknap (Member # 534) on 07-30-2006, 04:48 AM:

Yes, absolutely. Making a set of seps is the standard option for creating preservation masters from colour elements, where either the original has faded or you only have a combined positive (print) to start with. A less expensive option is to print through filtered light (the Bell & Howell 'C' printer has adjustable light veins which can be used to adjust the colour temperature of the light source to compensate for the faded original); but this isn't as effective on severely faded elements and of course it only gives you a chromogenic dupe. Seps give you the chemical stability of a b/w silver dye for preservation, whilst also recording the entire colour record.

The main drawback with seps is the cost and complexity. If I remember correctly, it was Robert Harris who pointed out that after Scorsese's fading awareness campaign in the early '80s, studios started making a set of preservation seps off cut camera negatives as a matter of policy, but often didn't bother making a recombined interneg for quality control. The result was that in some cases, serious registration errors were discovered many years later.

At AMIA last year we were shown a back-to-back comparison of a scene from Chinatown, once reprinted directly from the preservation seps and once from the 4k-scanned camera negative and cleaned up digitally. The digital version blew the photochemical one away - largely, we were told, because the latter had not been done with enough attention to quality control.

At the moment, the cost of digital intermediate restoration is still so high that in many cases, the photochemical route still costs a lot less to deliver an equivalent quality. I guess that Moore's Law means that this won't be the case forever, and at any rate photochemical restoration of colour faded elements needs the best lab guys and girls in the business, taking as long as the job needs, to get it right. The colour information is still there in the faded film; the trick is in making it visible to the naked eye again.

As for Kodachrome, I guess you could call it the ultimate home movie medium, having been invented by two people for whom photography was their hobby rather than their day job!

Posted by Christopher Seo (Member # 7) on 07-30-2006, 11:48 AM:

Leo,

Is/was "Chinatown" in need of restoration, or was this just a demonstration? The newer Warner Bros. print I've seen is almost certainly from the camera negative and looks amazing.

Posted by Charles Greenlee (Member # 3856) on 07-30-2006, 01:01 PM:

Ok. Well I'm glad to hear that I make sense, though a little disappoined I didn't start a revolution. [Wink]

Posted by Leo Enticknap (Member # 534) on 07-31-2006, 06:14 AM:

Christopher: what we were shown was in the context of a demo of the Sony 4k projector. A section of the interneg made by recombining the preservation seps and scanned 'as is' (i.e. with no attempt made to digitally correct the registration defects) was shown, followed by the same scene in which the cut camera negative had been scanned directly and the fading digitally corrected. The colour fringing was horrible on the former. There may have been an element of trying to flog d-restoration and d-cinema (after all, I'm sure it would have been possible to correct the registration issues digitally, as well), but it did make the point that you're only going to get the best result out of the preservation through seps route if you make a recombined neg to check the registration at the end of the process.

There are some pretty good IB prints of Chinatown still around here, meaning that it's possible to see it fade-free: so how much the film 'needs' restoration is a bit difficult to say. AFAIK there's no issue with incomplete versions in circulation or anything like that.

I am a bit worried if, as you say, they're striking release prints straight off the camera negative, though. Simply for physical issues (i.e. to minimise scratching, perforation damage and stuff like that), you want to be using that element as little as possible. Once you've made a f/g pos, you can then make as many subsequent copies as you like without disturbing the o-neg, or if you scan it, you can then make as many copies of the raw data as you need to work on. But there's only one camera negative, and personally I'd be cagey about using it to directly strike release prints, however good they're likely to look.

Posted by John Pytlak (Member # 331) on 07-31-2006, 11:39 AM:

Kodak published a method of restoring faded prints photochemically: "Corrective Reproduction of Faded Motion-Picture Prints" by C. Bradley Hunt in the July 1981 SMPTE Journal, Volume 90.

As mentioned, a pre-print element like the master positive, duplicate negative, or B&W separation positives is usually the best choice for making new prints or transfers.

Digital color restoration is routinely done for video transfers, and as the cost of 2K and 4K Digital Intermediate comes down, is being used more frequently for feature film restorations.

Posted by Christopher Seo (Member # 7) on 08-01-2006, 02:23 PM:

Leo,

I don't believe "Chinatown" was labeled as an OCN print, but that I judged it as such due to lack of lab cues, as well as very high sharpness and low grain (as judged by binoculars out the port window). If it was a fourth-generation print I'd be really impressed.

Posted by Tim Reed (Member # 137) on 08-04-2006, 04:20 AM:

quote: John Pytlak
Kodak published a method of restoring faded prints photochemically: "Corrective Reproduction of Faded Motion-Picture Prints" by C. Bradley Hunt in the July 1981 SMPTE Journal, Volume 90.

What did that method involve, John? How well did it work?

Posted by John Pytlak (Member # 331) on 08-04-2006, 10:34 AM:

quote: Tim Reed
What did that method involve, John? How well did it work?

It involved making either a "Dupe Mask" or a "Flashed Dupe Mask" on a color reversal film, then bipack printing it with the faded print to make a new internegative. It worked well, but as noted, a color print is not normally considered to be a preservation element.

Today, most would choose to make a corrected digital intermediate if only a faded print was available.