Film-Tech Forum ARCHIVE: HELP ! Light near the projector

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Posted by Tom Petrov (Member # 1534) on 12-31-2005, 08:39 PM:

Quick question. How much overhead light should there be near the actual film projector. Our booth is very bright with florecennt overhead lights right above the projector. Does this have any effect on picture quality and contrast.

Posted by John Pytlak (Member # 331) on 12-31-2005, 09:00 PM:

Any light in the projection room should NOT shine on the screen. Look at the unlit screen with the projector not running. Ideally, you should not be able to cast a shadow on the screen from any light source in the theatre or projection room.

The other issue with too much light in the projection room is that it may get picked up by the soundhead, especially affecting analog sound. Fluorescent lights are most likely to cause hum, but even a tungsten work light can cause hum.

Posted by Mike Olpin (Member # 1115) on 12-31-2005, 09:00 PM:

Also, light leakage onto the back of everyones head can be very distracting.

Posted by Frank Dubrois (Member # 3042) on 12-31-2005, 09:12 PM:

We have overhead lights too, but they get shut off when the first projector starts. After that, we have tow bulb type lights one shines on the platter, one on the projector for threading, then they get shut off after the movie starts.

Posted by Gordon McLeod (Member # 33) on 01-01-2006, 10:15 AM:

In many locations projection rooms are deemed by employment standards groups as machine rooms and there is different minimum light levels required depending on location

Posted by Louis Bornwasser (Member # 3063) on 01-01-2006, 11:03 AM:

Small lights are no problem near the projector. I install bright lighting (used while threading) and power it from the automation so that when the start button is pushed, those light go out. (same way as framing lamp) Louis

Posted by Mark Gulbrandsen (Member # 72) on 01-01-2006, 11:41 AM:

quote: Louis Bornwasser
I install bright lighting (used while threading) and power it from the automation so that when the start button is pushed, those light go out.

Then whatdayado if one needs to examine the machine whlie its running? Hopefully there's an auto-lights off bypass switch...... [Smile]

Sometimes I place an 8 foot fixture on the ceiling up tight to the front wall containing the ports. Light goes straight down and not out through the ports. There is no need to kill the light since none goes out though the ports. Like being on a bright sandy beach on a sunny day... all you need to complete the bright light is the Barbecue grill, some steaks, and a 12 pack!

An install I did outside id Indy a few years ago..... This one was not my idea(nor were the risers for the projectors!) but I thought it was a good one..... Florescent "running" lights mounted under the wireways are also sometimes a nice touch and illuminate the entire booth very well. Again because of being mounted tight to the front wall none will leak out through the ports. easy on the eyes, and provides enough light to see whats going in every nook and cranny without light leakage out of even very large ports. At least you shure as heck won't be tripping over anything.....

Mark

quote: Louis Bornwasser was the last to post

Posted by Brad Miller (Member # 2) on 01-01-2006, 12:17 PM:

Whoever wasn't smart enough to raise the entire booth floor in that picture above the 2-3 feet shouldn't be designing theaters.

I prefer regular flourescent fixtures centered between walls down the length of the booth with light directing grids on them so they don't shine out into the auditoriums. Then of course another fixture over each projector, also with a grid, connected to the automation (but yes, with an override switch).

Posted by Mark Gulbrandsen (Member # 72) on 01-01-2006, 12:33 PM:

quote: Brad Miller
Whoever wasn't smart enough to raise the entire booth floor in that picture above the 2-3 feet shouldn't be designing theaters.

I couldn't agree more. It WAS the guy's first attempt too. Wolf Theatres, Greensville, IN. The late Dave B. had too much of a hand in its design.

Grids limit the distance the light can travel and reduce light levels at the extremes.... not always a good thing. They also collect alot of dust and that dust gets released into the booth when the grids are dropped to re-lamp.... A really bad thing if you keep a clean booth.

Mark

Posted by Louis Bornwasser (Member # 3063) on 01-01-2006, 02:47 PM:

I really like the "floor" lighting effect.

BTW: the risers under those projectors sometimes have significant weight. One of the more-prolific architects in our industry has elevated projectors up to 5 feet on solid (or near solid)concrete. When I asked him if he had recalculated the sub-floor structural failure load, he replied "Oh my God." This was done after-the-fact when the projector was shadowed by the head sitting in the porthole. Louis

Posted by Mark Gulbrandsen (Member # 72) on 01-01-2006, 04:43 PM:

You're right Louis. We have run into trouble with that on one job with all DP-70's! The entire booth floor had to be re-inforced. Wasn't the architects fault at all, he specified the right structural stuff and floor thickkness.... it was the contractor's fault for not reading the blueprint correctly. The reinforcement was done at his expense needless to say.

Mark

Posted by Gordon McLeod (Member # 33) on 01-01-2006, 04:43 PM:

The first booth I ever saw with flourescent lamps below the raceways was the Bayview Village booth in toronto which was installed by Lorne Greere who was one of the original designers of the showman pegboard at famous players

Posted by Mark Gulbrandsen (Member # 72) on 01-01-2006, 08:42 PM:

quote: Gordon McLeod
which was installed by Lorne Greere

Wasn't he that guy on "Bonanza"?