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Author Topic: Correct Color Temp.
Bernie Anderson Jr
Master Film Handler

Posts: 435
From: Woodbridge, New Jersey
Registered: Apr 2000


 - posted 08-16-2000 10:40 PM      Profile for Bernie Anderson Jr   Author's Homepage   Email Bernie Anderson Jr   Send New Private Message       Edit/Delete Post 
Hi,

Does anyone know the correct color temp of the light source for film projection?

Bernie

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Scott Norwood
Film God

Posts: 8146
From: Boston, MA. USA (1774.21 miles northeast of Dallas)
Registered: Jun 99


 - posted 08-17-2000 05:30 AM      Profile for Scott Norwood   Author's Homepage   Email Scott Norwood   Send New Private Message       Edit/Delete Post 
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.

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Bernie Anderson Jr
Master Film Handler

Posts: 435
From: Woodbridge, New Jersey
Registered: Apr 2000


 - posted 08-17-2000 07:16 AM      Profile for Bernie Anderson Jr   Author's Homepage   Email Bernie Anderson Jr   Send New Private Message       Edit/Delete Post 
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

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Mark Gulbrandsen
Resident Trollmaster

Posts: 16657
From: Music City
Registered: Jun 99


 - posted 08-17-2000 07:58 AM      Profile for Mark Gulbrandsen   Email Mark Gulbrandsen   Send New Private Message       Edit/Delete Post 
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

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John Pytlak
Film God

Posts: 9987
From: Rochester, NY 14650-1922
Registered: Jan 2000


 - posted 08-18-2000 08:37 AM      Profile for John Pytlak   Author's Homepage   Email John Pytlak   Send New Private Message       Edit/Delete Post 
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

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Stan Gunn
Expert Film Handler

Posts: 176
From: Clematis, in the hills near Melbourne Australia
Registered: Aug 2000


 - posted 08-18-2000 06:45 PM      Profile for Stan Gunn   Author's Homepage   Email Stan Gunn   Send New Private Message       Edit/Delete Post 
I have used many evd 36volt 400 wattlamps
in arc lamps. all with good result, one had a throw of 50 foot.

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Bernie Anderson Jr
Master Film Handler

Posts: 435
From: Woodbridge, New Jersey
Registered: Apr 2000


 - posted 08-22-2000 10:09 PM      Profile for Bernie Anderson Jr   Author's Homepage   Email Bernie Anderson Jr   Send New Private Message       Edit/Delete Post 
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?

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