This is topic Correct Color Temp. in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.
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Posted by Bernie Anderson Jr (Member # 410) on 08-16-2000, 10:40 PM:
Hi, Does anyone know the correct color temp of the light source for film projection?
Bernie
Posted by Scott Norwood (Member # 30) on 08-17-2000, 05:30 AM:
Xenon light is supposed to be 5500 degrees Kelvin. Carbon-arc light should be similar. Tungsten should be about 3200 degrees kelvin. 16mm prints can be ordered timed for 3200k or 5500k light sources.
Posted by Bernie Anderson Jr (Member # 410) on 08-17-2000, 07:16 AM:
Thanks, I'm trying to retrofit a Carbon arc with a new lamp. Currently I have a halogen bulb mounted through a bracket on the Positive jaw, using the original reflector. On a small picture it looks really good. When you blow it up it looks very yellow and not that bright (it is a 1000 watt). I've been trying to resolve that issue with using some kind of xenon bulb used in intelligent stage lighting systems. I just wanted to make sure that the color would be right. Thanks
Posted by Mark Gulbrandsen (Member # 72) on 08-17-2000, 07:58 AM:
When I do dailies some DP's want both lamps matched and some don't care. I've always used the Minolta color temp. meter and let the DP or one of the camera crew do the actual color balancing using Kodak color compensating filters over the projection lens. This way they have done it and they are happy.
Mark
Posted by John Pytlak (Member # 331) on 08-18-2000, 08:37 AM:
Standard SMPTE 196M specifies: "For 35- and 70-mm prints, the light reflected from the screen in theatres shall have a spectral distribution approximating that of a blackbody at a color temperature of 5400K +600K -200K, the use of short-arc xenon light sources being assumed."A recent survey of review rooms and premier theatres showed some variation from this standard, with the average color temperature being about 5500K to 5600K. Some feel that D5500 (Daylight 5500) having a CIE Chromaticity of x=0.332 and y=0.347 would be a suitable "aim".
Note that the color of light specified is very close to natural daylight, which is a mixture of sunlight and "skylight".
------------------
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
Posted by Stan Gunn (Member # 554) on 08-18-2000, 06:45 PM:
I have used many evd 36volt 400 wattlamps
in arc lamps. all with good result, one had a throw of 50 foot.
Posted by Bernie Anderson Jr (Member # 410) on 08-22-2000, 10:09 PM:
Stan Gunn said "I have used many evd 36volt 400 wattlamps in arc lamps. all with good result, one had a throw of 50 foot."What is the evd 36volt 400 wattlamp? DC current I'm assuming? Does it match the color of xenon or carbon arc?