Film-Tech Forum ARCHIVE: Carbon arc color temperature?

This is topic Carbon arc color temperature? in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Jan Eberholst Olsen (Member # 10133) on 11-15-2017, 04:15 AM:

When projecting 35mm prints from the 50s and 60s, I assume that many of the prints were color timed for carbon arc projection?

It has been some years since I screened prints with carbon arcs, but I remember it as beeing slightly more yellow than xenon.

Should I aim for 5400K (or maybe even 5300K) reflector to "compensate" for the difference?

Posted by Gordon McLeod (Member # 33) on 11-15-2017, 08:11 AM:

I believe it was 5600K that was quoted in the national carbon books of years gone by
With Xenon one of the issues was that the reflectors had to be matched to lower the higher native colour of xenon

Posted by Frank Angel (Member # 248) on 11-15-2017, 09:11 AM:

If I remember correctly, xenon, besides having an overall higher kelvin, had some anomalies that were of some concern. The spectrum analysis of xenon light showed that it has some very sharp peaks in the green area that were oddly spaced and thus difficult to correct, whereas carbon arc showed a much smoother waveform. Evidently though, those green spikes were not detrimental enough to make any effort to compensate other than lamenting it(obviously the smoother the spectrum, the better). I remember a few meetings at SMPTE meetings in MY where some concerns were raised in lively discussions about the quality of xenon light. Back then not a lot of people were embarrassing of it, I would guess perhaps because it was new and people were trying to figure out how it would impact jobs now that a xenon lamphouse combined with a platter would surely change the roll of projectionists.

Posted by Steve Roberts (Member # 9544) on 11-16-2017, 03:54 AM:

Maybe this is a little off topic but I was asked if I would run a copy of The Wizard of Oz in a private cinema. The copy was over 80 years old, nitrate and like new! When I went in to the projection room I was confronted by 2 1950 Kalee 21 projectors with President carbon arcs.
I have never in all my time as a projectionist and engineer ever seen such a beautiful clean crisp full colour picture as that old print and the carbon arcs.

Posted by Jim Cassedy (Member # 4115) on 11-16-2017, 10:20 AM:

A 1975 info sheet I have from a now-defunct film lab states that their
"carbon arc prints" were timed for 5400k.

Posted by Rick Raskin (Member # 1561) on 11-16-2017, 04:39 PM:

quote: Steve Roberts
I have never in all my time as a projectionist and engineer ever seen such a beautiful clean crisp full colour picture as that old print and the carbon arcs.

Posted by Jan Eberholst Olsen (Member # 10133) on 11-17-2017, 02:57 AM:

Thank you for you inputs. I think I will aim for 5400K. When we screened DUNKIRK in 70mm (with 87mm Isco 8-perf lenses), the image is sharp and crips from edge to edge. During a rehearsal screening, I installed an original 87,5mm Isco Todd-AO lens. The result was better than expected, but for sure the lens gave "warmer" colors (and a bit softer overall image). Since modern lenses may add "blue/more cold color", maybe the image will look more correct onscreen with a (within the SMPTE spec) lower color tempreature (5200/5300K)?

Posted by Jeffry L. Johnson (Member # 453) on 11-20-2017, 10:32 AM:

SMPTE 196 specifies 5400 K + 600 K - 200K.

Multiple projectors shall match within a total range of 400 K.

Posted by Frank Angel (Member # 248) on 11-22-2017, 07:18 PM:

Ah, wouldn't the world be a great place if every theatre met SMPTE specs?!

I have heard people poo-poo the idea that nitrate prints had a unique "look." All you need to do is ask anyone who had seen or projected nitrate and there is never any equivocation about it -- the picture looks spectacular. I used to get nitrate TECHNICOLOR (!) prints...WB cartoons....at the theatre I worked at in Texas in the early 60. The difference was palpable. The image just seemed to shimmer, a quality I've never seen duplicated by any other film stock, or projection process (digital). I also was lucky enough to run Hitchcock's REBECCA and the combination of nitrate plus a silver-developed print was stunning. I sure wish someplace, somewhere on the planet, people could still actually experience how beautiful film was able to look.

Posted by Bill Brandenstein (Member # 7758) on 11-25-2017, 12:54 PM:

quote: Frank Angel
I sure wish someplace, somewhere on the planet, people could still actually experience how beautiful film was able to look.

Last time I was at Disneyland, it struck me that the little Main Street Theatre, and any other venue displaying classic Disney animation, is visually a pale shadow of what audiences originally saw in nitrate Tech. As the owner of a handful of 16mm Tech - nothing I have is lovelier - I can only imagine what those same titles would've looked like in 35 nitrate. So it saddened me to realize that there is nowhere in the world, including at the Mickey Museum where you'd hope most of all it might be possible, where someone can view Disney animation as it was originally seen.

I know, I know, you're thinking: you're just NOW figuring this out?

Posted by Rick Raskin (Member # 1561) on 11-25-2017, 03:14 PM:

Frank: You hit the nail on the head.