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This topic comprises 2 pages: 1 2
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Topic: Stange white lines in top picture ??
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John Pytlak
Film God
Posts: 9987
From: Rochester, NY 14650-1922
Registered: Jan 2000
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posted 11-04-2002 04:06 PM
The pulldown for each frame is 4 x 0.1870 = 0.748 inches. Standard SMPTE 195 specifies the height of the "scope" projected image area to be 0.690 inches, leaving only 0.748 - 0.690 = 0.058 inches for the splice overlap not to show.SMPTE RP111 specifies the splice overlap (Dimension A) to be 0.049 inches for laboratory splices, but recommends "To minimize projection of splices, the width of the laboratory splice should be no greater than 0.040 in (1.02mm)". Annex A4 of RP111 says "CinemaScope splices can be made with an overlap of as little as 0.030 in (0.76mm)". As I noted, there are well-established negative cutting techniques that can be used to have "invisible" splices. ------------------
John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Research Labs, Building 69, Room 7525A
Rochester, New York, 14650-1922 USA
Tel: +1 585 477 5325 Cell: +1 585 781 4036 Fax: +1 585 722 7243
e-mail: john.pytlak@kodak.com
Web site: http://www.kodak.com/go/motion
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John Pytlak
Film God
Posts: 9987
From: Rochester, NY 14650-1922
Registered: Jan 2000
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posted 11-05-2002 07:26 AM
Kodak does supply some color negative and reversal camera films with ESTAR base. For example, EASTMAN EXR 100T Color Negative Film SO-256, KODAK VISION 500T Color Negative Film SO-579, EASTMAN EKTACHROME Film 2239, etc. Uses include 65mm IMAX cameras used in space, and high speed instrumentation cameras. I agree that cameras could be engineered to deal with the strength of polyester film, and ultrasonic splicing could be optimized for use in conforming negative originals, but triacetate base still seems to be preferred for today's production system.Of course, protection IPs and DNs can be made on KODAK VISION Color Intermediate Film (ESTAR Base) 2242, and separation positives on KODAK Panchromatic Separation Film (ESTAR Base) 2238:
here 2242
here 2238 ------------------
John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Research Labs, Building 69, Room 7525A
Rochester, New York, 14650-1922 USA
Tel: +1 585 477 5325 Cell: +1 585 781 4036 Fax: +1 585 722 7243
e-mail: john.pytlak@kodak.com
Web site: here
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John Pytlak
Film God
Posts: 9987
From: Rochester, NY 14650-1922
Registered: Jan 2000
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posted 11-05-2002 12:49 PM
Unlike some other film manufacturers, Kodak has consistently recommended tension-sensing failsafes between the platter and projector when using polyester film. IMHO, the best designs allow some slack using a movable "trolley", allowing the projector to coast to a stop if an abnormal tension buildup shuts things down.------------------
John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Research Labs, Building 69, Room 7525A
Rochester, New York, 14650-1922 USA
Tel: +1 585 477 5325 Cell: +1 585 781 4036 Fax: +1 585 722 7243
e-mail: john.pytlak@kodak.com
Web site: http://www.kodak.com/go/motion
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John Pytlak
Film God
Posts: 9987
From: Rochester, NY 14650-1922
Registered: Jan 2000
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posted 11-06-2002 10:08 PM
Polyester film has been used since the mid 1950's, in a variety of storage conditions around the world. Unlike nitrate and triacetate, I have not seen any ESTAR base degradation ever reported, but perhaps Leo or other archivists here on Film-Tech could relate their experiences or any reports of degradation.All IMAX prints have been on ESTAR base print film since the early 1970's. AFAIK, most airline prints (e.g., In-Flight, Transcom) were made on polyester base film. Here is a link to information about "vinegar syndrome" with triacetate base that has been stored improperly:
here Here is general information about film base:
here
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John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Research Labs, Building 69, Room 7525A
Rochester, New York, 14650-1922 USA
Tel: +1 585 477 5325 Cell: +1 585 781 4036 Fax: +1 585 722 7243
e-mail: john.pytlak@kodak.com
Web site: here
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John Pytlak
Film God
Posts: 9987
From: Rochester, NY 14650-1922
Registered: Jan 2000
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posted 11-08-2002 07:58 AM
Yes, the Molecular Sieves adsorb acid vapors and moisture, and the film and Molecular Sieves need to be in a sealed container. Molecular Sieves are so effective in adsorbing moisture that you can actually measure a weight gain within a short time of being exposed to the open air! Weight gain can be used as a measure of when the Molecular Sieves are saturated and need to be replaced.Fully vented containers also can be used reduce build-up of damaging acid vapors. Of course, then you need to condition the entire storage area to the recommended (SMPTE RP131) low relative humidity of 20 to 30 percent for optimum long-term storage.
here Molecular Sieves ------------------
John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Research Labs, Building 69, Room 7525A
Rochester, New York, 14650-1922 USA
Tel: +1 585 477 5325 Cell: +1 585 781 4036 Fax: +1 585 722 7243
e-mail: john.pytlak@kodak.com
Web site: http://www.kodak.com/go/motion
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Leo Enticknap
Film God
Posts: 7474
From: Loma Linda, CA
Registered: Jul 2000
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posted 11-08-2002 10:17 AM
First off, I've never heard of any evidence to suggest that there are base decomposition issues with polyester. Steve's point is a valuable one - just because we don't know of any issues does not mean for sure that there aren't any. After all, nitrate decomposition wasn't discovered until the 30s, and there was no systematic research on VS until the 70s. But we do know that there are definitely serious issues with all of the alternatives, hence polyester is now the archival storage base of choice.As for molecular sieves vs. vented cans, there are pros and cons with both. The sieves need to be inspected and replaced regularly, but as the can is sealed, there is no danger of offgases contaminating any other element in a vault. As John points out, vented cans (e.g. Dancan or Stil) are only any good if temperature, humidity and air circulation are up to the job of removing the fumes. If not, then offgases from a badly decomposing element can accelerate the process in one which started out in a much better state.
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