Film-Tech Forum ARCHIVE: What is Scotchguard?

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Posted by Leo Enticknap (Member # 534) on 02-20-2001, 12:59 PM:

I've noticed that old release prints from the 70s and 80s often arrive in rusty old tins with sticky labels that say 'Scotchguard Protected' (complete with a 3M logo). Whenever I open them, the reel invariably stinks of some awful chemical (acetone at a guess) - sometimes the smell is so bad as to completely mask the vinegar syndrome! The film is usually very shrunk and brittle (although of course 20 year-old acetate gets that way without any help from other treatments), whilst the base is often sticky and discoloured.

I guess this stuff must have been a scratch resistant coating or film cleaning agent which worked in the short term, but has damaged the film over decades of storage. Is this the case? Does anyone know what the chemical composition of Scotchguard was, how widely it was used or anything else about it?

Posted by Derek Maxwell (Member # 234) on 02-20-2001, 01:27 PM:

That is news to me. I know it has been used recently on new Polyester stocks but I have never seen it used years ago and never saw an effect like that. I wonder if it does have an effect like that on all newer prints that were treated? I personally don't have any of my new Drive-in Intermission films done like that since it costs so much to have it done. I think if you get new film and keep your machine clean and use something like Filmguard, you would be much better off.

New 35mm Intermission films http://www.drive-infilm.com

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http://www.drive-infilm.com

Posted by Jerry Chase (Member # 660) on 02-20-2001, 01:35 PM:

This month's Scientific American has an article on scotchguard. Apparently segments of one of the main chemicals are nearly indestructable. I can't think of a good reason to scotchguard film and am puzzled why it was done.

Posted by John Pytlak (Member # 331) on 02-20-2001, 01:56 PM:

Here is a link to information about 3M SCOTCHGARD Film and Photo Protector:
http://www.3m.com/market/consumer/photogard/index.html

It can be used both on duplicate negatives and prints. It is a polymeric coating that is applied to the film and then cured (hardened) with intense ultraviolet light. It is impervious to most solvents and water, and cannot be removed.

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John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Eastman Kodak Company
Research Labs, Building 69, Room 7419
Rochester, New York, 14650-1922 USA
Tel: 716-477-5325 Cell: 716-781-4036 Fax: 716-722-7243
E-Mail: john.pytlak@kodak.com
Web site: http://www.kodak.com/go/motion

Posted by John Walsh (Member # 168) on 02-20-2001, 02:00 PM:

It was not widely used, at least not in the US. I only saw one print with it (a Woody Allen film, forget the title.)

You needed special splicing tape; regular tape wound not stick to it. In fact, very little would stick to it, including dirt. At the time (about 15 years ago) we dunked a short length from the tail leader into old pizza sauce, soda, etc. It was weird how nothing would stick. I remember thinking how someone will be digging this stuff 2000 years form now, because it will never go away!

You could see a texture to it, sort of like brush strokes, when the light reflects off of the film. Didn't see anything on screen, though.

Scotchguard and Film Guard were made for different purposes; Scotchguard kept the film from getting dirty, Film Guard cleans the film if it gets dirty.

I never heard of Scotchguard damaging film; My understanding is/was it was just too expensive to use on new prints, where 90% of the prints just get thrown away after the initial release. It was also expensive to treat older prints, because they must be cleaned throughly before applying the Scotchguard. Usually, no one wants to put any money into maintaining old prints.

Posted by Ken Layton (Member # 133) on 02-20-2001, 02:55 PM:

Scotchguard is what used to be called 3M Photoguard. It was a hard coating applied to reduce scratching to prints. Evidently it sealed the film so well that vinegar syndrome was accelerated on Photoguarded prints because the film couldn't breathe!

In the days before Polyester prints some distributors payed extra for the Photoguard treatment with acetate prints they thought would get extended runs in theaters.

Filmack Studios was a big proponent of Photoguarding their snipes and datestrips.

Posted by Leo Enticknap (Member # 534) on 02-20-2001, 02:59 PM:

According to the web link John P posted, this stuff was first sold in 1978. 3M claim that it "won't yellow or delaminate with age". A very difficult claim to evaluate, I would have thought - if you're dealing with a 20 year-old element, there are so many other things that could cause the emulsion to fade or the base to delaminate (e.g. acetylation, faulty developing, storage conditions) that it would surely take a very determined analytical chemist to find out whether or not the Scotchgard played any part.

It would be interesting to compare the condition of two reels from the same print (i.e. same stock batch, same lab, same storage conditions), one which had been SG coated and one which had not.

Posted by Scott Norwood (Member # 30) on 02-20-2001, 03:54 PM:

Apparently, this stuff is (was?) sometimes used on IMAX prints. The idea is that supposedly it makes scratching the film nearly impossible. As Ken mentioned, there are many reports of this causing vinegar syndrome in acetate-base prints (which is probably the situation that the original poster describes).

Scotchguard (the chemicals) is also sometimes used on carpet; in theory, it helps to prevent staining, although I have no idea whether or not it is effective. (I suspect that it is.)

Posted by John Pytlak (Member # 331) on 02-20-2001, 06:08 PM:

AFAIK, "SCOTCHGARD Film and Photo Protector" and SCOTCHGARD fabric protector are completely different and unrelated technologies developed by 3M.
http://www.mmm.com/market/consumer/photogard/index.html
http://www.mmm.com/market/consumer/chemical/index.html

Dacar Products Company makes similar UV-cured film coatings called Imagegard:
http://www.dacarprod.com/www/ndatesh

Posted by Joe Redifer (Member # 3) on 02-20-2001, 07:11 PM:

"Scotchguard and Film Guard were made for different purposes; Scotchguard kept the film from getting dirty, Film Guard cleans the film if it gets dirty."

I must disagree here.

Filmguard is made to improve the presentation of any theatre, primarily by keeping prints clean from the get go. You can use it effectively to clean dirty prints, yes, but it was made to stop the cause, not treat the symptom.

Scotchguard (and its evil twin Imageguard) to my understanding exist to "rejuevenate" prints. It is applied only to the base side only (really helpful for preventing emulsion scratches). It does run through the projector louder and rougher. Many of the treated prints often shed like no tomorrow, actually making the onscreen presentation much dirtier and far worse. In its defense, it is near impossible to put a scratch on the base side of a treated print. And John is definitely right... it's impossible to remove!

Posted by Gordon McLeod (Member # 33) on 02-20-2001, 07:17 PM:

Photoguard has been applied to both the emulsion and base sides of film.
It prevents most minor scatching (cinch marks and the likes)
But a major disaster will scratch a print
It was first used on alternateing reels of JAWS

Posted by Derek Maxwell (Member # 234) on 02-20-2001, 09:33 PM:

Is there a way to do this yourself in any way? I wonder if my Rejuvination machine can be converted to do this?

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http://www.drive-infilm.com

Posted by David Kilderry (Member # 142) on 02-21-2001, 04:49 AM:

As a circuit that uses around 100 Filmack trailers, I can vouch for the Photoguard process. It certainly does protect the film and with animation at least does not cause any noticeable colour change.

We have run some trailers every day for years and the quality is still evident.

David

Posted by Jeff Taylor (Member # 443) on 02-21-2001, 06:34 AM:

For what it's worth, I've got a number of late '70 vintage Samuel Goldwyn titles (the Danny Kaye series) which were photoguarded. I can't speak to its effectiveness in preventing scratches as I'm careful with my prints, but it also hasn't caused any VS, warping, cupping, or ribboning to date. 'Guess I'll keep my fingers crossed!

Posted by Dick Vaughan (Member # 540) on 02-21-2001, 06:39 AM:

Ahh! The smell of a photoguarded print.

I have two prints of the Imax film "To Fly" which are photoguarded and date back to 1983.
Each has at least 2500 passes on them ,the colour is a little faded but not a scratch on them.

When this protection is properly applied it's truly wonderful. However we have had badly treated prints on a number of occasions in the past and this results in small amoeba like transparent pieces flaking off and sticking to the field lens.

Posted by Carl King (Member # 398) on 02-21-2001, 07:31 AM:

Scott:

Scotchguard for fabric is, as John Pytlak says, a completely different animal. You mentioned about carpets. Well, Ive used it on the cloth upholstery and carpets of all my vehicles for over 15 yrs (3 kids) and I'm pleased. It sure helps keep stains down to a minimum.