Film-Tech Forum ARCHIVE: RCA "Evenlite" Screens

This is topic RCA "Evenlite" Screens - Did They Work? in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Jim Cassedy (Member # 4115) on 02-27-2014, 09:48 AM:

This old advertisement is for something calld the RCA "Evenlite" screen,
which claimed to eliminate hot spots by varying the size of the perforations,
from large perfs in the center, tapering off to none at the sides.

Has anybody actually seen one of these? Did they actually work?

This ad is from 1951, so it pre-dates multi-channel stereo sound and cinemascope.

Posted by Frank Angel (Member # 248) on 02-27-2014, 11:43 AM:

Since the screen isn't the cause of the placement of the hot spot but the projector optics and the position of the viewer (the hot spot is in a different place unique to where the viewer is sitting), a uniform gradation of the holes from center to edges would only generate a secondary uneven distribution of light "beating" as it were against the actual position of the hot spot.

Then there'd be the negative sonic effect of uneven sound obstruction that immediately comes to mind.

Things that work usually catch on. The fact that you've never seen one of these says volumes about how effective they were. that said, I've never seen lenticular silver screens which were one of Fox's CinemaScope spec and which was said to grately reduce the hotspot of the high gain silver. Evidently the reason those aren't made any more is, I was told by a guy at MDI, that they are muy expensive to manufacture.

I must say though, you have to hand it to the manufacturer (probably not RCA), to be able to get those holes graduated must have been quite a feat. What would be even better today, if someone could make a screen with RANDOM perfs so as to avoid the dreaded potential of moire patterns. Seems if these guys could control perfs to this precise degree, it should be easy enough to do random perfs.

Posted by Steve Guttag (Member # 268) on 02-27-2014, 12:21 PM:

Stewart screens are effectively random perfs...they are hand applied and it shows. Of course, there is the price of Stewart to contend with.