Film-Tech Forum ARCHIVE: Beige Powder

This is topic Beige Powder in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Richard Quesnelle (Member # 391) on 07-13-2000, 08:27 PM:

I noticed last week this beige powder all over the intermittent sproket teeth and all the other sprokets and teeth. I am just wondering if this is a form of film shedding, because we are playing the Patriot and ever since then this has shown up. If it is, how long does shedding normally last and do most films shed?

Thanks __Reg

Posted by Gordon McLeod (Member # 33) on 07-13-2000, 08:30 PM:

Will be happy to supply you with some film guard and the problem will go away

Posted by Rick Long (Member # 213) on 07-13-2000, 10:32 PM:

Yeah Richard, just about all new prints do cover the interior of your projector to some degree, some worse than others. Fortunately, it can easily be brushed away with a soft brush. Using lens tissue and lens cleaning fluid will take care of the deposits on the back element of the lens.
Generally, as the print becomes more "worn in", the problem decreases.

Posted by Ethan Harper (Member # 472) on 07-13-2000, 11:32 PM:

I too have had this problem with film-shed. No matter how many times you clean the projector out, the film will continue to shed during each show. The best solution that i would reccomend is getting Film-Guard. Otherwise you will be having to clean out film-shed between each and every show. I would also reccomend using the new film-tech media pads to use the film-guard with.

. They are the softest (so it sont scratch) but yet the most durable (you can clean your lenses with them). They are less hassle than Kelmar (and cheaper) and they come with the film-guard cores all ready to go for you. (how convenient

Not only will it get rid of your shedding problem, it will also clean your print during each run, lubricate and clean your gates, and will give you the cleanest picture you will ever see . Honestly it would be the best thing you could do for you booth and would be the best suggestion for you problem.

I believe Film-guard is distrubuted through
NCS, ASC anything else you might want to check.

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--"That's my story and i'm sticking to it!"--

Posted by Ethan Harper (Member # 472) on 07-13-2000, 11:35 PM:

Oh oops and another thing before i forget,

have you been having this problem before?
When did it start.

is the shedding only observed by the intermmitent? is that where it seems to start.

i would check the alignment on your shoe pad.

what kind of projecor are you using?

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--"That's my story and i'm sticking to it!"--

Posted by Michael Cunningham (Member # 210) on 07-14-2000, 02:53 AM:

Beige dust!?! Are you sure? The stuff I've seen always came out purple, causing us to semi-affectionately refer to it as "Purple-saurus-rex". Kidding aside, everybody here is right, Film-Guard will clear that right up!

-Mike

Posted by John Pytlak (Member # 331) on 07-14-2000, 06:28 AM:

"Purple" dust is usually magenta-colored emulsion debris, and is sometimes seen on freshly processed prints. When film is processed, the gelatin emulsion swells like a wet sponge. When dried, it sometimes doesn't shrink completely back to its original size, leaving an edge that slightly overhangs the film edge and perforations. The first few times through a projector, this overhang is scuffed off by rollers, guide rails and sprocket teeth. The magenta dye layer is the topmost imaging layer in print film, so most of the scuffed debris is from the magenta layer. Using a film cleaner during projection removes this debris before it becomes attached to the film.

Beige debris may be a mix of emulsion layers and back-side scuffing. I agree with Ethan that you should check the tension and alignment of the intermittent sprocket shoe.

As posted elsewhere on this forum, certain projectors are more prone to cause abrasion of the back-side of the film, which shows up as white flaking. Kodak has made recent improvements to VISION Color Print film to make it even more resistant to back-side abrasion by these projectors. Significant improvement has been verified by Kodak's tests and the reported experience of theatres.

Kodak has always recommended proper lubrication of release prints after processing to reduce abrasion and optimize projection performance. Film lubrication is part of the ECP-2D processing specification:
http://www.kodak.com/US/en/motion/support/processing/h249/index.shtml
http://www.kodak.com/US/en/motion/support/processing/h242/h2402_04.shtml#164364

SMPTE Recommended Practice RP151, "Lubrication of 35-mm Motion-Picture Prints for Projection", also recommends edge waxing for optimum performance of release prints.

Unfortunately, environmental restrictions on the use of methyl chloroform have caused labs to discontinue edgewaxing of prints. Alternative solvents are usually more hazardous or flammable.

As noted, proper use of film treatments containing a lubricant can help reduce projector abrasion of the processed film in those theatres having abrasion-prone projectors.

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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 Fax: 716-722-7243
E-Mail: john.pytlak@kodak.com