Film-Tech Forum ARCHIVE: Possible contrast killer question.

This is topic Possible contrast killer question. in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Alan Gouger (Member # 543) on 03-27-2007, 06:42 PM:

Something I have always wondered. Most projection booths keep some lights on. Even though the theater is dark part of the projection path from lens to screen starts out in the booth for about a foot or so before entering the dark theater. Does booth lighting hitting that foot or so of exposed projection beam cause any loss in contrast.

Posted by Monte L Fullmer (Member # 2797) on 03-27-2007, 07:04 PM:

quote: Alan Gouger
Does booth lighting hitting that foot or so of exposed projection beam cause any loss in contrast.

..something not to get all worried about since this weak outside light isn't within the same travel of the projected beam, which is tons brighter.

Posted by Cameron Glendinning (Member # 3516) on 03-27-2007, 08:44 PM:

Not regularly cleaning ports and dusty lenses are the real contrast killers.

Posted by Kyle Anderson (Member # 3504) on 03-27-2007, 08:46 PM:

The light interference from the two angles/beams does not exist once you leave that volume of beam intersection - so the screen will not be affected, unless the ceiling light is shining directly on the screen (not likely).

Posted by Dave Macaulay (Member # 813) on 03-28-2007, 08:53 AM:

Beams of light do not interact. Contrast can be affected by lots of things, but you could intersect the projection beam with spotlights, other projector light beams, any number of megawatt laser beams, whatever... and not affect the picture contrast (or any other picture quality)in any way if none of the intersecting light beams fall on the screen directly or through reflection.

Posted by Alan Gouger (Member # 543) on 03-28-2007, 11:06 AM:

quote: Dave Macaulay
Beams of light do not interact. Contrast can be affected by lots of things, but you could intersect the projection beam with spotlights, other projector light beams, any number of megawatt laser beams, whatever... and not affect the picture contrast (or any other picture quality)in any way if none of the intersecting light beams fall on the screen directly or through reflection.

Thank you. Thats what I was looking for.