Film-Tech Forum ARCHIVE: Green specks in analog soundtrack

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Posted by Michael Barry (Member # 237) on 05-31-2000, 11:56 AM:

Our theatre received a print of 'Galaxy Quest' for a private hire that takes place in a few days...while inspecting the print tonight, I noticed that reels 2-5 (mildly in reel 1) have what look like green emulsion scratches throughout the analog soundtrack. They progressively get worse and more frequent throughout the reels. They are not continuous, just tiny linear marks, like flecks of paint. (I don't have ready access to a scanner, otherwise I would upload a sample.) Looking more closely, there are also fine diagonal emulsion scratches in the image area on the soundtrack side in a 'herringbone' array throughout.

I projected one of the reels and the soundtrack reproduces with an awful, constant buzz particularly from the right channel (like the DTS track was being scanned). We're using a tungsten exciter lamp. Obviously, we'll have to obtain a replacement by the weekend as the dialogue is almost drowned out by the noise(!) and we do not have any digital playback equipment.

Looking at the shipping label that was on the case, the print has only been to one multiplex for the season (which has just finished here).

Any suggestions as to what could cause this 'speckling' pattern and why the scratching is so apparent and extremely concentrated in the analog soundtrack area? My guess is that the silver content of the analog area would betray problems more readily than the image area...The color of the track (what's left of it!) is magenta.

Posted by Mark Huff (Member # 480) on 05-31-2000, 12:13 PM:

Sometimes a projectionist will thread sound track down and if not done properly can scratch the film. Cinemark has a projection trainer in California that trains all the projectionists that way.

Posted by John Pytlak (Member # 331) on 05-31-2000, 12:30 PM:

Michael:

From your description of the damage, I agree with Mark that it was likely abrasion of the emulsion on the analog soundtrack side of the film, probably by rubbing on a rough platter surface or riding up on a roller. However, if the scratches are producing a regular "buzzing" or "motorboat" sound, rather than random "pops", they may be from sprocket teeth.

Most analog soundtracks in use today are the "high magenta" tracks, with only the magenta layer (it has the best sharpness) and its silver carrying the soundtrack information. "High Magenta" tracks are compatible with both red LED and tungsten light sound readers.

------------------
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