Film-Tech Forum ARCHIVE: Blue fibres

This is topic Blue fibres in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

To visit this topic, use this URL:
https://ft-forum.com/ft/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=1;t=002428

Posted by Steve Riddle (Member # 781) on 06-28-2001, 05:03 PM:

Can anyone tell me how a blue fibre type material is cloging up our projector, it is coming off the non audio edge of the print yet there is no sign of any print damage and only occurs now and then, slight deposits can be seen on the centre payout pulley assy.
Many thanks

Posted by Paul G. Thompson (Member # 655) on 06-28-2001, 06:18 PM:

Check your lateral guides and film paths very carefully. Something is "crowding" the film as it passes through the projector. Also inspect your film paths to and from the platter.

Posted by Christopher Duvall (Member # 284) on 06-28-2001, 06:47 PM:

It almost sounds like something in the gate might be "shaving" the outer edges of the film. Does the print have blue dye on the edges or an SDDS soundtrack on it? Also check on what Paul suggested.

------------------
Chris Duvall
General Manager
Regal Cinemas Colonnade14
Las Vegas, NV

Posted by Randy Stankey (Member # 64) on 06-28-2001, 07:00 PM:

On rare occasions when the film is cut into strips it will have rough edges. When it goes through your projector the edges will be "shaved" off by the projector and these little hairs will fly all over the place. It will usually go away after the first run or two.

If it's not a brand new print that's been running for a while when it starts having this problem then I would agree you have a problem in your film path. Aslo, even if it's a brand new print but the problem doesn't go away by itself by the end of the first day you also have a problem.

Sometimes there can be residual "hairs" left over on the print and it will seem to keep shedding even after you have verified that the problem (if there actually was one) has been solved. Just run it through your print cleaner a couple of times. (Preferably with Film Guard)

Posted by Rick Long (Member # 213) on 06-28-2001, 07:22 PM:

The "now and then" factor may be a clue.

Is there any relationship between the source of the prints (e.g. "it seems to happen more with one distributor or lab").

Is it evident enough to be seen after the first run? If so perhaps a clue to the source of the problem can be seen. In your examination of the projector/sound-head, for example, is there a point above which, no blue fibre is found?

I am wondering, if this is a multiple theatre, is the problem occuring on more than one machine. If so, perhaps logical deductive trouble-shooting would be in order. Perhaps gates and /or traps could be switched to see if the problem travels.

Is one projectionist only experiencing the problem? Maybe a casual "drop-in" call might permit you to inconspcuously examine the threading.

Posted by Jerry Chase (Member # 660) on 06-28-2001, 09:49 PM:

What brand and model projector?

Posted by John Pytlak (Member # 331) on 06-30-2001, 01:12 PM:

During processing, the gelatin emulsion swells as it absorbs the aqueous processing solutions. When the film is dried at the end of the process, the gelatin emulsion usually shrinks back to its original size. But sometimes, there is a "lip" or overhang of emulsion on the edge of the film, that can be scuffed off during the first few passes through a projector, generating hair or debris.

Randy Stankey said: "On rare occasions when the film is cut into strips it will have rough edges. When it goes through your projector the edges will be "shaved" off by the projector and these little hairs will fly all over the place. It will usually go away after the first run or two."

A "rough edge" from slitting would usually cause a severe "white dirt" problem in the film lab, so it's unlikely that it is the cause of hairs in the projector, unless there is a corresponding high level of printed-in "white dirt" on the print.

I agree with Paul that if every print through this projector seems to generate "angel hair" emulsion skivings, something is "pinching" the film and scuffing the edge.

------------------
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 Cell: 716-781-4036 Fax: 716-722-7243
E-Mail: john.pytlak@kodak.com
Web site: http://www.kodak.com/go/motion