8mm Forum: The truth about Vinegar Sydrome!

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Posted by Kevin Wardle (Member # 1680) on August 29, 2009, 01:04 PM:

Hi,

Could anyone tell me the truth about Vinegar Sydrome, is it safe to store with other films, does it cause any damage to the film itself? What signs other than smell should I look for?

Many thanx, Kevin.

Posted by Mark Mander (Member # 340) on August 29, 2009, 01:24 PM:

Hi Kevin,
I've only ever come across one vinegar print in the past,the other sign i noticed was that the film had a sticky feel to it as well,i wouldn't have a print with it in my collection.As for it passing to other films,i guess it's possible but don't know for definate,i'm sure this topic has been mentioned in the past,try in the search section....Mark.

Posted by Michael O'Regan (Member # 938) on August 29, 2009, 01:40 PM:

Despite varying opinions on this, nobody knows for sure whether or not VS is transmissible to other prints. Different collectors will provide evidence for one or the other belief. Having said that it would seem to make sense to keep any VS prints stored separately from your other prints.
Better safe than sorry and all that!!
[Smile]

Posted by Kevin Wardle (Member # 1680) on August 29, 2009, 01:44 PM:

Hi Mark,

Thanx for that mate. I did a search but it came up with zilch! [Confused]

I got some films off of E bay and they smell strong, might be a film cleaner smell, the films aren't sticky at all. I like the films you see, and some of them are very old! 'Scat Cats', which is a Castle cartoon (and is my favourite) has been dated 1945/47 according to my Castle reference book 'Castle Films: A Hobbyist's Guide'! [Wink]

So I really don't want to bin em if I don't have to...

Anymore help would be very much appreciated!

Kevin.

Posted by Michael O'Regan (Member # 938) on August 29, 2009, 01:49 PM:

If its VS there will be an unmistakable smell of vinegar.

Posted by John Whittle (Member # 22) on August 29, 2009, 03:43 PM:

There have been experiments where a film with VS was placed in a can with a normal film and indeed in a tightly controlled can, the other film contracted VS as well.

One major thing we've learned is that film needs to breathe. Don't store in tight metal cans and never tape them closed. Best storage conditions are lower temp and normal humidity. Too dry and the film will have other problems since the emulsion is composed of gelatin and if you dry it out it cracks.

VS is actually a breakdown of the acetate base into it's base elements and once it starts it continues. It can be slowed down with cold storage, but with respect to all those who swear by their tonics, it can't be corrected.

Nitrate film turns to goo and then dust, Safety film can develop VS but by no means is it universal and some films from the 30s are fine and stuff from the 60s is bad. Kodachrome seems very unlikely to get the problem and ironically its the one film that Kodak made on di-acetate.

There is lots of information out there on VS and Kodak covers it in one of their books on Care and Storage of Motion Pictures (or they did when they still printed those books).

John

Posted by Kevin Wardle (Member # 1680) on August 29, 2009, 04:00 PM:

That's great, John, thanx.

Posted by David Kilderry (Member # 549) on August 30, 2009, 02:47 AM:

As John says, do not store in air tight tins or cans. Film needs to breath in order to dispell any chemical build-ups. Mine are now all on open spools; carboard boxes are OK, cans are good for transport however.

The Kodak website and others have tones of information on the subject.

Posted by Dino Everette (Member # 1378) on August 30, 2009, 03:11 AM:

the simple answer is yes it is contagious - vinegar syndrome involves gases that are offing from the film as its chemical composition is breaking down. The gases can migrate to other films. The best prevention for spread is to isolate the vinegar films from your healthy ones - especially for most small collectors who simply keep the films at home, since generally you don't have air circulation systems that constantly replace the air with fresh air, if your air circulation is just that...circulating the same air, then the gases are probably going to find the way over to the other films. The kodak molecular sieves that they sell can be used to absorb the gases being ofed to help prevent a spread, but it obviously cannot stop the process.

Posted by Michael O'Regan (Member # 938) on August 30, 2009, 03:35 AM:

So the gasses can then initiate VS in another print?

I was under the impression that VS began chemically within the affected print and was not initiated from without.

Posted by Simon McConway (Member # 219) on August 30, 2009, 04:32 AM:

I read recently that collectors should not keep their films in cardboard boxes as these can trigger vinegar syndrome! I disagree with this.

Where I keep my films, two extractor fans are installed. Every so often, these are switched on to draw out all of the stale air. It may be doing very little, however, it's better than nothing!

Posted by Kevin Wardle (Member # 1680) on August 30, 2009, 12:18 PM:

Very interesting guys, keep the comments coming as they will be useful to other collectors!

Many thanks, Kevin.

Posted by Dino Everette (Member # 1378) on August 30, 2009, 03:48 PM:

Michael yes while the VS originally does start within a reel of film breaking down all on its own the gases that are being released are not neutral, but harmful gases that can then in turn speed up the breakdown of healthy film because it is changing the overall purity of the air that healthy film is breathing in...Think of it in terms of second hand smoke. While it is obviously worse for the person ingesting the smoke initially (ie: the film that developed the VS all on its own) the presence of that contaminant in the air can have negative affects on anyone else in the room that then breathes it in (ie: the other healthy reels of film). In part this is the same basis behind the comments about people not storing films in boxes. The only reason is the paper in the boxes can "absorb" things which in turn can be harmful for ones' films. For Instance if you had a film that developed mold, it could be spread by the air circulation to the other boxes which would absorb the moisture and would then create an outbreak (I once had to hire and supervise a special cleaning crew to take every reel of film out its can and clean it at the small archive I was working at, because we had an air conditioner leak over the weekend and the moisture in the air got picked up and transported through the vents to all of the shelves (which at that time were wooden, which caused the moisture to stick and soak into the shelves ) and by Monday it had turned into spots of mold all over the cans of film....

I think for most home collectors the paper boxes are perfectly fine, but when you get into the thousands of items you really need the vented plastic archival cans, because you can't necessarily just empty the room of everything should you have the presence of moisture, etc...

Also don't forget that the chemical composition of every type of film is slightly different not just between nitrate, diacetate, & triacetate, but literally every batch of Kodak triacetate is different in some way, mainly because they all got processed at different labs using different formulas, etc.... At my work we run films through an old style traditional tinting bath when preserving old silent movies, and we have to take our color formula and run 3 or 4 test passes with adjustments to match a color because as soon as the tint hits the emulsion it reacts completely different on each and every print because of the emulsion and processing variances....

Posted by Michael O'Regan (Member # 938) on August 30, 2009, 04:55 PM:

Thanks, Dino, for the explanation.

I'm wondering then, why there is ANY difference of opinion regarding VS being transmissible from print to print.

From what you describe, it would appear to be pretty conclusive.

Posted by Mark Todd (Member # 96) on August 30, 2009, 05:29 PM:

Only VS ones I got went straight in to the Wheelie Bin in a few layers of plastic.

I am amazed people will even buy wanted films with it in progress, absolutely mad.

But then again most if not all of us left in the hobby probably need some serious therapy !!!!

Best Mark.

Posted by Dan Lail (Member # 18) on August 30, 2009, 08:00 PM:

If you dip them in liquid Jello, then soak them in lye with a smidgen of Worcestershire sauce at temperature of...oh say ..-10 degrees they will be just right for the old "wheelie bin". [Big Grin]

Love the "wheelie bin" thing booby. [Big Grin]

Posted by Dino Everette (Member # 1378) on August 31, 2009, 02:42 AM:

quote:
I'm wondering then, why there is ANY difference of opinion regarding VS being transmissible from print to print.

short answer - because unless something is as straight forward and as easy to understand as 1 + 1 = 2, it will be debated....

slightly longer answer would involve the fact that there are enough instances where a reel of film will sit right next to an infected reel and NEVER develop VS, providing the fuel for argument. This is in keeping with what I said about the fact that the film being acetate is only part of the equation, the other parts, such as the chemical mixture that was used in the processing of the film, is completely different every single time a film is processed, and this level of variance cannot be accounted for making the equation more something like "VS will contaminate other films in proximity UNLESS special inexplainable factors are present."

Here is a quote from page 14 of the IPI storage guide for Acetate Film)The Image Permanence Institute is the only place I know of who are routinely and specifically testing these types of arguments in relation to media storage over time.

quote:
Laboratory experiments show that acetic acid
vapors are readily absorbed by fresh film, and this will
lead to faster deterioration. In practice, however, it's
quite difficult to judge when a threat actually exists.
Where at all practical, films showing vinegar syndrome
should be segregated.

Basically what they are saying is that the controlled tests show that this is the case, but in real life situations there are many unpredictable variables that can make it less clear cut...The question then becomes is it worth the risk to keep your vinegar films in with your healthy films? If you think there is no risk then by all means feel free to treat vinegar films the same as your others, I was only trying to answer Kevin's question with information obtained from those studying this phenomenon, rather than try and push personal beliefs, or something..

Posted by Michael O'Regan (Member # 938) on August 31, 2009, 06:03 AM:

Thats an excellent summary, Dino.

I wasn't questioning your beliefs, or whatever else you think. I was genuinely interested.

I'm not sure why some people get a little put out if they're questioned a little closely on a particular topic - if we don't ask we'll never find out.

Posted by John Whittle (Member # 22) on August 31, 2009, 10:23 AM:

Michael,

The other thing to remember is that the tests used to forcast a problem over time have not proven to be very accurate. Both time/temp/light tests used for film (and paper prints) have been bad predictors of fade and damage.

Look how long it took to find cyan image fade, and then there are cases of nitrate film from the 20s being fine and projectable and other films have turned to dust.

The bottom line is alot of the "predictors" turn out not to work. In some cases (like 100 year ink jet non-fade inks) we won't be around to see if they're accurate, in other cases such as storage conditions and VS, you won't find out for years if a theory you read about is true or not.

So use your best judgement, but don't look for absolute answers--there are just too many variables.

John

Posted by Dino Everette (Member # 1378) on August 31, 2009, 01:53 PM:

Michael
I didn't mean to sound put off by being questioned. Not in the slightest, but I did want to make clear, that I was not simply some guy that thinks he knows all about everything (HA far from it [Eek!]

) I wanted to make clear that it wasn't my own philosophy on VS but the studies that are being done, I just was trying to point out that, if nothing else, the tests show that the spread is highly possible and very likely so why would you (as in anyone...not you personally) want to risk it. I have nothing against anyone, nor do I get my feelings hurt so easily....howzabout a cyber shake on it? [Big Grin]

PS John points it out the clearest, the biggest thing to consider is that no answer or theory on storage is truly time tested except the fact that for some reason some nitrate we know can last 100+ years and still be in projectable shape, beyond that we are all still guessing and learning as time passes.

Posted by Michael O'Regan (Member # 938) on August 31, 2009, 01:57 PM:

Dino,

A cyber-shake it is, sir.
[Big Grin]

Posted by Hans van der Sloot (Member # 494) on August 31, 2009, 02:55 PM:

VS is a very strange phenomena.
I have 3 super-8 digests from Picollo with VS. Each digest has 2 reels.
Strangely enough from all these digest only 1 reel from each digest has VS, the other not.
So 3 reels have VS, the other 3 not.
One digest is even brand new. The films are still sealed in plastic.

Posted by Kurt Gardner (Member # 440) on August 31, 2009, 09:05 PM:

Sealed in plastic? Even worse! I bought a brand-new 400' sealed super 8mm "Shaft" off eBay and wouldn't even run it because it stank so bad when I unwrapped it.

Posted by Hans van der Sloot (Member # 494) on September 01, 2009, 05:47 AM:

Yes, I know. Film should be able to "breath".
I didn't even unwrapped these films.
But that's not my point.
It's strange that films from a same batch and always stored together in the same conditions, react differently to VS.

Posted by Winbert Hutahaean (Member # 58) on September 08, 2009, 12:32 PM:

Hans, I understand your situation because I have the same problem too.

From all readings above, it seems to me no one include the lab process and stocks used as the result of VS.

I think Hans' problem may be resulted from lab process and stock batch (because I remember some one explaining here that in making 2/3 parter sometimes was done in different batch between the part).

So my assumption is that your healthy part reels come from a right chemical process while the other is not. The word "right" here means very subjective, i.e "Right" to your current environment/climate. So it can be a different scenario if (for example) the reels are in my country. Probably the healthy reels will get VS, while the other are the opposite.

My last question, will the LPP stock get VS too? anyone here find VS on your LPP prints (8mm or 16mm)?

cheers,

Posted by Michael O'Regan (Member # 938) on September 08, 2009, 01:23 PM:

Any acetate film can get VS. This can include LPP or indeed any stock.

Only Mylar prints are immune.

Posted by John W. Black (Member # 1082) on September 12, 2009, 01:34 AM:

Storing film in cans in a humid room will hasten VS. And despite claims of some,it cannot be cured,only treated to slow the process.Kodak tried to come up with a solution in the 70s and gave up.

Posted by Mark Todd (Member # 96) on September 12, 2009, 05:14 AM:

Bin em or burn em !!!

Best Mark.

Posted by David Kilderry (Member # 549) on September 16, 2009, 01:54 AM:

I tossed a 16mm feature last week; the VS smell was so strong it nearly made you pass out when i openned the plastic can. The layers of film were also stuck together. It had been completely sealed for years.

It had come from Queensland, a northern Australian state; think Florida and add some more heat and humidity!

Posted by Brad Kimball (Member # 5) on November 08, 2009, 09:31 PM:

What about the MGM titles that came in the black plastic hinged cases or the Universal-8 plastic cases? Do these promote v/s?

Posted by Douglas Meltzer (Member # 28) on November 08, 2009, 10:18 PM:

Brad,

I've had films in both the MGM and Universal 8 clamshells come down with VS. The films need some air. Keep 'em cracked open a bit.

Doug

Posted by Brad Kimball (Member # 5) on November 08, 2009, 10:47 PM:

Both parts of "A Night At The Opera" have a sort of soury aroma. Not horrible, but it's definitely there.

Posted by Vangelis Lympouridis (Member # 1753) on November 10, 2009, 10:12 AM:

I am confused...and I smell vinegar at most of my films too...
Do doth B&W and Colour films suffer from VS first of all?
I bought 6 films that arrived today and I smell them again and again trying to realize if they smell vinegar or it is simply an old grandpa's closet smell...
It gets even more confusing since one of the reels has a gentle perfume aroma...
Doctor, is it me or my films???

Posted by John Whittle (Member # 22) on November 11, 2009, 11:21 AM:

First, any estar/mylar film will not have the VS smell.

Second many if not most sound striped prints will have an "aroma" about them. That is not VS.

Open a bottle of your best punget vinegar and take a whiff (it'll probably really be strong)--that's what you're looking for.

Most 8mm films that have been stored "in the open" don't suffer from this, rarely Kodachrome which was diacetate will have the problem.

Remember the smell is the first stage, then sticky or the film is curly and hard to hold flat and focus. If you find a reel or two, store them in a different location.

John

Posted by Bill Brandenstein (Member # 892) on November 11, 2009, 02:56 PM:

John, can you tell us more about Kodachrome being diacetate? Didn't Kodachrome change to triacetate at some point? And why would Kodak make a diacetate film when everything else is/was the other (until Estar)? TIA

Posted by John Whittle (Member # 22) on November 12, 2009, 09:25 AM:

I really would have to go back and do some research. Kodachrome was a very early color product but I don't think that was the reason of the different base. They probably did change at some point, but there was a reason that the camera films were on that support. The print films (Kodachrome Print 5269 and Eastman Reversal Color Print 7387) were on triacetate.

John

Posted by Bill Brandenstein (Member # 892) on November 12, 2009, 11:07 AM:

So those of us who shot Kodachrome in the 70s and 80s were probably dealing with Triacetate? Let alone the latest stock?

Posted by Adrian Winchester (Member # 248) on November 12, 2009, 06:29 PM:

[ November 13, 2009, 11:11 PM: Message edited by: Adrian Winchester ]

Posted by John Whittle (Member # 22) on November 13, 2009, 10:03 AM:

This is from a fifty cent Kodak book "Storage and Preservation of Motion Picture Film" This is the early blue cover edition, I have a later one somewhere but the following will be of interest to some:

"The base of support of acetate motion picture film, which is approximately .0055 inch in thickness is usually made from cotton or wood cellulose by chemical treatment which coverts it into a plstic. In former years, most motion picture film support was of the highly flammable, cellulose nitrate type. The only "safety" or slow-buring films up to about 1938 were made from acetone=soluble cellulose acetate. These were followed by the cellulose acetate propionate and acetate butyrate types. In spite of the hazardous nature of nitrate film and the safety precautions which were necessary in the handling and storage of this materi, it was preferred over the early types of acetate film for commercial 35mm use because of its superior physical characteristics.
In recent years, an improved safety support made of high acetyl cellulose acetate (commonly called "cellulose triacetate") has been developed and this new safety support is fully suited to the rigid requirements of commercial motion picture use. As a result, the Eastman Kodak Company has not manufactured any nitrate film in the United States since 1951.
Although virtually all Eastman 35mm motion picture filmas as well as 16mm black and white motion picture films are now made on triacetate support, Kodachrome Film is currently made on cellulose acetate propionate support. Kodachrome andEastman Color Films were never made on nitrate base, but imbibition color print and various two-color print stocks were made on nitrate film for a number of years prior to 1951.

The current Kodachrome spec sheet makes no metion of film support.
http://www.kodak.com/global/en/professional/support/techPubs/e55/e55.pdf

The current Care and Storage publication is now 12 pages and is here:
http://www.kodak.com/global/en/consumer/products/techInfo/e30/e30.pdf

There is a Kodak Publication, which I could not find on line: "The Book of Film Care" publication H-23.

The publication quoted has no copyright date, but the back page has a code 3-57 and I would guess that's the revision date of the book.

John

Posted by Vangelis Lympouridis (Member # 1753) on November 13, 2009, 12:53 PM:

Hello,

Excuse me if that is irrelevant but should a film be firm on its reel or quite relaxed? Sometimes I use a microfibre cloth while I rewind the reel so to clean it off from dust but that causes the film to be a bit firmer than usual back on its reel. Does it mean that it cannot breathe properly? Any possible connection to VS there?
Thanks
Vangelis

Posted by John Whittle (Member # 22) on November 13, 2009, 03:02 PM:

An interesting point that hasn't been directly addressed. However, since the major Hollywood Vaults are now storing film horizontally in film containers that allow air circulation, I wonder if a more "relaxed" wind might not be better.

Remember, however, that most negative and sound tracks are stored on cores, tails out wound with a tite-wind. So perhaps it's not a critical issue, but an interesting point. Also most of the work has been done on 35mm film and narrower gauges would not be as adversly effected.

I most transcribe some of the research notes on testing acetate film base circa 1948-1950 and the published results. One of the problems with the research is it was all done with elevated temperatures and concerned itself with film brittleness--a previous problem with film support. Hence no one considered the problem of breakdown with moisure, but certain problems with fumes were addressed and problem with certain air conditions in areas with heavy coal burning industries.

In all a fascinating study considering what we learned fifty years later.

John

Posted by David Michael Leugers (Member # 166) on December 14, 2009, 10:00 PM:

Just a note or two on a very interesting subject... Vitafilm, while a good product similar to Film Renew, is most definitely NOT a cure or even a treatment for VS. I did an experiment with it on beautiful print of a great B+W episode of Gunsmoke I had that was turning VS. I soaked the film completely submerged in Vitafilm for 6 months. It projected fine right after that. I stored it in a loose can so it could breath for about 1 year. I was horrified to discover last month that the film had completely warped into being unable to project status and the stench was incredible. Sad to see it go...

The other thing is that after all the years I have owned (never a large collection) of S-8mm and R-8mm prints, I have never had a VS print. 16mm several...

I personally think that if a film is not VS, then storing in a can is no problem. Only once it starts going it needs to keep the fumes away so as not to accelerate the process. Just my 2 cents. I had some 16mm color and B+W original home movies I shot that had been stored in taped up cans for 30 years without problem. They were as fresh and pliable as the day they went in.

Posted by John Hermes (Member # 1367) on December 16, 2009, 10:18 PM:

I do film transfer work and see a lot of old film. Almost every reel of VS film which comes my way has been stored in a tightly sealed can. While every film which has been stored in a can may not turn vinegar, almost every film which is vinegared has been in a can, in my experience.

Posted by David Michael Leugers (Member # 166) on December 30, 2009, 07:04 PM:

Just took my 16mm print of "Dawn Patrol" with Errol Flynn out with the trash. VS overcame this print even though I treated it with full submersion in Vitafilm for 3 months. After I took it out I thought the treatment had done a lot of good. Stored on open reels but only 6 months later what was a print starting to smell turned into a warped vile mess unable to be projected. Man that hurts.

Posted by John Hermes (Member # 1367) on December 30, 2009, 10:34 PM:

David, I'm sorry to hear of your plight. I had an LPP print of "The Bramble Bush" that went VS faster than any I have ever seen. I had to throw it away as well...nothing helped.

Posted by Michael O'Regan (Member # 938) on December 31, 2009, 02:56 AM:

David,
Did you try Pete Goed's LFP on the print?

Posted by David Michael Leugers (Member # 166) on January 02, 2010, 12:50 PM:

Michael

No I didn't. I did find out that you now can buy it via Paypal even though the website doesn't list this as a payment type. He is away until January 20, and I plan to order some after that date.
The print was so far gone, mounted on good metal reels the film was so wavy and misshaped, and smelled so horribly strong, I didn't feel it was possible or worth it. I have a few others that could use the LFP treament. Even though it supposedly puts VS film back into a pliable and projectable condition, you have to redo the treatment every few years.

Posted by Brad Miller (Member # 2) on January 02, 2010, 06:46 PM:

quote:
I do film transfer work and see a lot of old film. Almost every reel of VS film which comes my way has been stored in a tightly sealed can. While every film which has been stored in a can may not turn vinegar, almost every film which is vinegared has been in a can, in my experience.

This has been precisely my findings as well.

quote:
Did you try Pete Goed's LFP on the print?

There is NO CURE for vinegar syndrome, LFP included.

Posted by Michael O'Regan (Member # 938) on January 03, 2010, 02:30 AM:

Absolutely correct, Brad - I never suggested LFP could cure VS.

What I have had results with is getting rid of warp and getting a severely warped print back into projectable shape, with LFP.

I suggested that rather than bin the print, as David had to do, LFP my have allowed him to salvage it.

Posted by Bill Brandenstein (Member # 892) on January 04, 2010, 02:48 PM:

A new thought about home movies, VS, and which support the films might be made on. (For the previous post with amazing technical data, see John Whittle's 11/13/2009 10AM post.)

First, a little technical review based on John's post above. The first safety films were not just one chemical approach (cellulose diacetate) but three: acetone-soluble cellulose acetate, cellulose acetate propionate, and acetate butyrate. Then at some point most of it shifted to "high-acetyl cellulose acetate" which we normally refer to as cellulose triacetate.

Any of our studio or Blackhawk prints would be on this base, and when you view light through the side of the reel, have a medium amber color. Some films are lighter or darker than others, but triacetate prints never seem to be opaque, nor as light as mylar/polyester/estar prints, which are quite a bit more transparent through the film base.

Here's the new point. All the Super 8 Kodak stock that I have, from my first roll in the 70s, right up to current Plus-X and 64T rolls (sorry, have never shot negative) and recent Kodachrome, are opaque. Even with a bright light, almost no light gets through its side. Lest you think this happens because of different emulsion properties, this is still true even when the emulsion is removed with bleach. With no emulsion, it still is nearly opaque.

So at this point I would propose the radical opinion that ALL Kodak 8mm camera film is on diacetate TO THIS DAY. based on the fact that it looks like no other film through the side. Is diacetate less prone to VS than triacetate? I can't tell, but 100-year-old Edison films have turned up on eBay in projectable condition. However, I've seen old Kodachrome with VS.

Posted by John Hermes (Member # 1367) on January 04, 2010, 09:08 PM:

I have seen lots of Kodak camera film, B&W and Kodachrome, with VS. Most of it is from the mid-1930s and 1940s, but once in a while even films from the 1950s have it. Once again, the stuff stored in the tight cans is most prone, from my experience.

Posted by Bill Brandenstein (Member # 892) on January 05, 2010, 10:57 AM:

Yes, I would agree with you on that John (Brad too). Always in cans, and the same vintage.

Posted by Bill Brandenstein (Member # 892) on January 07, 2010, 10:20 AM:

Anyone want to respond to my suspicion that all Super 8 camera film is diacetate to this day?

Posted by John Hermes (Member # 1367) on January 07, 2010, 01:00 PM:

Whenever I have seen the base of Kodachrome specified it has been triacetate propionate. According to this report, Kodak discontinued diacetate films around 1940.

http://louisville.edu/library/ekstrom/special/files/Acetates

Posted by John Whittle (Member # 22) on January 07, 2010, 01:29 PM:

I don't think Kodachrome was on diacetate, what I found was:

"Kodachrome Film is currently made on cellulose acetate propionate support."

I haven't been able for find any reference where this was changed and why that emulsion was made on that base may relate to the coatings or the coupler/color developers in processing. In any event, it would show as a difference in edge transmission. As I recall 7387 had a different edge look that 7381 (Eastman Reversal Color Print/Eastman Color) which was also different from Ektachrome Print and Ektachrome R Print (7386/7388).

The base material for 7386,7388 and 7381 were all identical so it must have been an observation based on some other factor. 7386 and 7388 didn't have the rem-jet backing but a silver colloidal (sp) anti-halation layer. 7381 and 7387 however did have a rem-jet backing (a carbon black back of film coating that was removed in the first stage of development).

There was a black light test for nitrate/safety film but that was because a chemical had been added to all the safety film materials to make that test possible.

John

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