Film-Tech Forum ARCHIVE: Does ester count as acetate?

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Posted by Mark Haskett (Member # 2981) on 05-10-2006, 09:42 PM:

Are cellulose ester and cellulose acetate the same thing?
If not, how can I prove that all modern movies are now printed on polyester.
I need some direction!

Posted by Darryl Spicer (Member # 711) on 05-10-2006, 10:00 PM:

No they are not the same. I am not going to get into the chemical make-up of the two. I will leave that to John P. but I will say that Acetate Tears a hell of a lot easier than Polyester does. If you have some Acetate film laying around get a piece of it and a piece of polyester and ask someone to tear it. Start with the acetate then give em the Polyester and watch their reaction.

Posted by John Pytlak (Member # 331) on 05-10-2006, 10:06 PM:

Cellulose triacetate is an ester:

http://www.kcpc.usyd.edu.au/discovery/glossary-all.html

quote:
Ester
Take a carboxylic acid and an alcohol and remove water, so that you are left with two bits linked by a C(O)-O- group - this is an ester. Many of the most important industrial polymers are esters. For example, ethyl acetate.

Kodak's trade name for polyethylene terephthalate (polyester base) is ESTAR base. Not the same thing.

Other trade names for polyester film are MYLAR, GEVAR, CRONAR.

http://www.kodak.com/US/en/motion/support/h1/base.shtml

quote:
Base

* Manufacture of Film Base
* Antihalation Backing
* Edge Numbers
* EASTMAN KEYKODE Numbers
* Dimensional Change Characteristics
* Temporary Dimensional Change
* Permanent Size Change
* Other Physical Characteristics
* References

Posted by Mark Haskett (Member # 2981) on 05-10-2006, 11:43 PM:

Ok, so according to the link ( http://www.kodak.com/US/en/motion/support/h1/baseP.shtml#edge ) that John provided (thanks John):
Two general types of film base are currently used by Kodak--cellulose triacetate (acetate) and a synthetic polyester polymer known as ESTAR
also:
ESTAR Base, a polyethylene trephthalate polyester, is used for some KODAK Motion Picture Films (mostly intermediate and print films).

Is the print I am running of MI3 ester? yes, of course.
Is there some id mark on the print that proves it is ester? I looked at the links John provided and the print markings pertain to many things but not that...

How can I show that we are running ester prints?

My wife, a former chemical engineer for Shell (now a lawyer), and the smartest person I know, just told me that it sounds like ester is not even a cellulose.
John?
(sorry for my tone, I have city officials to placate)

Posted by Aaron Sisemore (Member # 145) on 05-11-2006, 12:45 AM:

Modern film stocks (since 1995-ish) are polyester. NOT celulose ANYTHING. Period.

One question though:

Why does it matter whether the prints are cellulose based or not?

As far as city officials go, both acetate and polyester film stocks are 'safety film' for the purpose of placating a fire marshal.

-Aaron

Posted by Monte L Fullmer (Member # 2797) on 05-11-2006, 01:22 AM:

Prob due to the cantankerous environmental idiots who wanted a substance that is recyclable as with polyester.....

[ 05-11-2006, 02:26 AM: Message edited by: Monte L Fullmer ]

Posted by John Pytlak (Member # 331) on 05-11-2006, 09:05 AM:

The color print films from all three major manufacturers now use polyester base. Agfa-Gevaert was the first manufacturer to promote the use of polyester base film for 35mm release prints in the early 1990's. During the 1990's, Kodak spent over $200 Million (USD) to develop the technology and base making machines needed to address the issues of base-side dusting and static cling that were more problematic with earlier polyester release prints.

The ESTAR base used for Kodak VISION Color Print Films has proprietary polymeric process-surviving scratch-resistant conductive anti-static layers coated on the back side.

Most motion-picture camera films still use cellulose triacetate base. Kodak B&W print film is still available on cellulose triacetate base(5302), but most B&W release prints use ESTAR base (2302).

Again, cellulose triacetate is a chemical "ester", but it is not known as "ESTAR", the trade name for Kodak's polyester base.

Posted by Michael Schaffer (Member # 1204) on 05-11-2006, 09:13 AM:

Man, and I always thought mylar and polyester were two different materials. Good that I swing by here regularly. There is something new to be learnt every day.

Posted by Stephen Furley (Member # 1277) on 05-11-2006, 10:36 AM:

John, I don't know when polyester film was first introduced, but I do know that Fuji Single-8 film, and some makes of Super-8, but not Kodak, were on polyester base in the mid-late '60s. Why did it take so long to become accepted for use in 35mm release prints?

Posted by John Pytlak (Member # 331) on 05-11-2006, 12:30 PM:

quote: Stephen Furley
John, I don't know when polyester film was first introduced, but I do know that Fuji Single-8 film, and some makes of Super-8, but not Kodak, were on polyester base in the mid-late '60s. Why did it take so long to become accepted for use in 35mm release prints?

Kodak has been making polyester base for almost fifty years (originally licensed from DuPont Chemicals), mainly for special venue films, smaller print formats, graphic arts and x-ray films.
But for 35mm release prints, Kodak wisely invested in improving some of the characteristics like projector dusting and static, that took over $200 Million in R&D and capital improvements about ten years ago. We also encouraged the development of proper tension-sensing failsafes by equipment manufacturers to properly deal with polyester's much higher tensile strength.

Posted by Richard P. May (Member # 3598) on 05-11-2006, 12:39 PM:

The simplest way to determine if a print is on Estar is to hold the reel up to the light. If you can see the outline of your hand through the side of the roll, it is Estar. If it does not pass light, it is acetate.
Also, as mentioned above, it is almost impossible to tear Estar.
Cut it with scissors or a knife, yes, but tear by hand without it being started some other way, doubtful.

RPM

Posted by John Hawkinson (Member # 1135) on 05-11-2006, 05:03 PM:

Not exactly the most definitive methods, Richard. It's like saying, "I know it when I see it." Fine if you already know, but not-so-fine if you don't.

For modern filmstock from Kodak or Fuji, look for the magenta edgecode in the SDDS area outside the perforations. If it's Kodak, then the first number will in all likelyhood be "2383" or "2393", indicating Kodak Color Vision ESTAR-base, or Kodak Color Vision Premiere ESTAR-base, respectively. (In fact, anything starting with "23" is a 35mm ESTAR-base. "53" is 35mm acetate.)

--jhawk

Posted by Frank Angel (Member # 248) on 05-11-2006, 06:26 PM:

The use of polyester Mylar base audio recording tape predates film by many years -- we have been holding reels of tape up to the light to determine if it is poly or acetate since the early 80s. But here's a question, we have thousands of upon thousands of reels of recorded audio much of which is on acetate stock. So how come triacetate film is so susceptible to acidosis (VS) whereas not a single 10in reel of any of our acetate audio tapes, at least to my knowledge, has ever gone vinegar? I would imagine they are a different variation of acetate, no? I mean, physically they are very different animals.

Posted by Mark Haskett (Member # 2981) on 05-11-2006, 09:37 PM:

Ok, look at the edge for the number "2383" or "2393" (thanks John H.). Those numbers are the id numbers pertaining to the kind of film used in the printing process.
Now, where can I find an industry chart (maybe somewhere in the EK website) that confirms the meaning of the edge numbers?
Thanks

Posted by John Pytlak (Member # 331) on 05-11-2006, 09:45 PM:

quote: Frank Angel
But here's a question, we have thousands of upon thousands of reels of recorded audio much of which is on acetate stock. So how come triacetate film is so susceptible to acidosis (VS) whereas not a single 10in reel of any of our acetate audio tapes, at least to my knowledge, has ever gone vinegar? I would imagine they are a different variation of acetate, no? I mean, physically they are very different animals.

The most likely reason is that audio tape is usually stored in cardboard boxes, or other containers that "breathe", so any acid vapors are not trapped. It's also easier for acid vapors to escape from a 1/4 inch thick tape roll than a roll of 35mm film. Film has often been stored in metal cans or metal film cases, with little chance for acid vapors to escape, so the trapped acid accelerates the reaction. Kodak developed Molecular Sieves to adsorb moisture and acids in sealed container storage, greatly slowing the "vinegar syndrome" reaction. When it comes to film storage, "cool, dry, and vented" are the by-words.

Posted by Aaron Sisemore (Member # 145) on 05-11-2006, 11:22 PM:

quote: Frank Angel
we have been holding reels of tape up to the light to determine if it is poly or acetate since the early 80s.

However, in the case of open reel tape, its ACETATE that lets light shine through and polyester is totally opaque. (the reverse of 35mm film) I assume it has something to do with the base thickness of acetate vs poly.

quote: Frank Angel
So how come triacetate film is so susceptible to acidosis (VS) whereas not a single 10in reel of any of our acetate audio tapes, at least to my knowledge, has ever gone vinegar? I would imagine they are a different variation of acetate, no? I mean, physically they are very different animals.

I have see reels of acetate base tape go vinegar. Almost always the tapes were stored in plastic bags or in metal film-style cans.

Acetate base tape also degrades in much the same manner as its 35mm counterpart (especially if stored in less-than-ideal conditions: It will begin to shrink, causing the tape to curl and twist, making it difficult to maintain precision head contact. It also will get very brittle at this stage, making transport almost impossible in some cases without the tape breaking.

-Aaron

Posted by John Hawkinson (Member # 1135) on 05-11-2006, 11:49 PM:

Mark asks, "Now, where can I find an industry chart (maybe somewhere in the EK website) that confirms the meaning of the edge numbers?"

Kodak seems to've reorganized this stuff umpteen times since I last saw it, but I'm sure it is there somewhere. If you look at the Technical Data Sheet for 2383, under Identification, it says:

quote:

Processed film has magenta edgeprint (compatible with digital sound) with the following information printed along the length of the film: "2383/3383 (strip number) KODAK (date)".

2383/3383 Film is only available on ESTAR support, and is never on triacetate support.

Hopefully that's good enough for you. I think there's a more general set of explanations about edgecodes somewhere, though.

--jhawk

Posted by Monte L Fullmer (Member # 2797) on 05-12-2006, 03:33 AM:

Hey Frank .. have any of those poly tapes have the backcoating where they get that 'sticky shed' syndrome to where you baking those reels of tape to get the moisture out of the backing material?

Do agree, seen acetate tape stored in an airtight situation where they do go to vinegar....

Posted by Stephen Furley (Member # 1277) on 05-12-2006, 07:49 AM:

Triacetate base recording tape hasn't been available over here for a very long time; I think the last time I saw any on sale was probably in about the late '60s. The environmental conditions in some of the film vaults that I've seen have not been good, and this certainly wouldn't help. All other things being equal, recording tape should be more prone to this, as the presence of FE(III) ions, as in iron oxide tape coatings, tends to accelerate the process.

Does diacetate film base suffer from the same problem?

Posted by John Pytlak (Member # 331) on 05-12-2006, 08:05 AM:

Information about Kodak edgeprinting information is available on the Kodak website, and some of the sites that deal with film archiving:

EASTMAN KEYKODE Numbers

quote:
KEYKODE Identification Numbers

Triacetate Base - Estar Base - Keykode Number ID

Datecode Symbols

quote:
Until 1982, the date code was comprised of two symbols except for the following years:
1916, a circle; 1917, a square; 1918, a triangle; and 1929, a plus sign. For 1928 and
1948, three circles were used to identify the year of manufacture.
Date codes were repeated every twenty years until 1982. For example, the same symbols
appear on film manufactured in 1921, 1941, 1961 and 1981. In 1982, a third symbol was
added allowing for many more years of unique date coding.
Starting in 2001, date symbols will no longer be used for films without KEYKODE Numbers.
The actual date of manufacture will be part of the latent edgeprinting on these films.

KEYKODE Numbers

quote:
What are KEYKODE Numbers?
EASTMAN KEYKODE Numbers are machine-readable bar codes on Eastman film stock that exactly replicate the human-readable key number. They are printed every half foot and include a reference dot that identifies the frame to which each number applies.

http://www.sabucat.com/pdf/dcc.pdf

quote:
THESE ARE THE DATE CODE CHARTS FOR EASTMAN KODAK MOTION PICTURE FILM AND DUPONT FILM. READ THE SYMBOLS ON THE
EDGE MARKINGS OF THE FILM FROM LEFT TO RIGHT, AND COMPARE TO THE CHART. THIS WILL TELL YOU WHEN THE FILM WAS
MANUFACTURED AND WHERE. WHITE PRINTING TELLS THE INFORMATION ABOUT THE NEGATIVE, AND BLACK PRINTING TELLS THE
INFORMATION ABOUT THE POSITIVE PRINT. EXAMPLE: THE BLACK PRINTING READING LEFT TO RIGHT ON A PRINT OF "THE
PRODUCERS" IS " + + ". THE CHART TELLS US THAT THIS IS A PRINT STRUCK IN 1968, WHICH INDEED IS WHEN THE FILM WAS
RELEASED.

In addition, specific information about the edgeprinted product code is usually included in the technical datasheet for each Kodak motion-picture film on the Kodak website.