AFAIK, it had to do with optimizing the efficiency of a video display --- you could get more light at the higher color temperature. Standard SMPTE 196M traces the film projection color temperature specification back to the days of high intensity carbon arc, which was very close to natural daylight. Xenon arc is very similar. There is some variation, mostly due to differences in dichroic coatings and optics, rather than the lamps themselves.

A recent technical paper on the subject was published in the SMPTE Journal: Berggren, Glenn, The Color of Light on the Screen -- New Measurements at Studios and Laboratories, 106:156, Mar. 1997.

There is ongoing discussion within the SMPTE DC28.8 Digital Projection Study Group regarding color temperature, with a push to specify a higher color temperature than 5400K for Digital Cinema.

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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 Cell: 716-781-4036 Fax: 716-722-7243
E-Mail: john.pytlak@kodak.com
Web site: http://www.kodak.com/go/motion

I recall that the Vista Pro used a CERMAX Xenon lamp module. What size lamp (watts) did yours take? What did the replacement module cost?

Surprised to hear the new xenon lamp blew the "ballast". (The term "ballast" implies a metal halide lamp). Isn't the power supply filtered DC with high voltage ignition, similar to a regular xenon lamphouse? Wasn't there a fuse or current limiter to protect the power supply from the "shock" of changing lamps?

------------------
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 Cell: 716-781-4036 Fax: 716-722-7243
E-Mail: john.pytlak@kodak.com
Web site: http://www.kodak.com/go/motion

I would think that the studio types would NOT want the 5400K increased based on my dealings with them in premier situations. In fact, they seem to prefer it on the lower side to keep flesh tones looking good. As the color temp increases to 6000K, people start to look dead.

Generally, when I have a screening room or a theatre that does more than it's share of studio screenings and where dailies and such might be run, the spec I use on the reflectors is 5400K +0/-200K but matched to each other (if 2-projector). It is within SMPTE spec and keeps the studio types happy.

I am working on a lab project now where the projector must put out either 5400K or 3200K!!! Oh what a pain! Since some of the 16mm film is destined for tungsten illumination, they want the 3200K reference as well.

Steve

Actually, this will be Kinoton's problem. There will actually be two filters, one for 5400K and one for 3200K. As I understand it, they are going to have the light coming out of the lamphouse higher than 5400K and filter it down to 5400K or 3200K as necessary. Since it is for a lab, they are fussy!

This puppy will do 16, Super-16 and 35mm, forward or reverse from 1 -30 fps projection, and up to 100fps shuttle (in either direction), all remoted with projection speed on a read out....Talk about your bells and whistles!

Steve

My own preference would be to go with a D5500 specification, or the same color temperature as average "daylight". It would reflect the latest data such as Glenn's. But it would also be the same as the light most of us look at the outside world with--- DAYLIGHT.

As you know, the light output of a high intensity carbon arc or xenon arc film projector is very similar to natural daylight, whereas the "white" on a video projector is really a combination of red, green and blue light, with "gaps" in-between.

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