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trichromatic photography


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#1 anthony le grand

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Posted 21 July 2008 - 05:57 PM

Hi all,

can someone explain to me what is trichromatic photography please? I just now that it's what Cunningham used for some video clips but I don't know exactly how to get this effect and what is exactly the consequence on the footage..

Thanks a lot!
Anthony
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#2 Adrian Sierkowski

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Posted 21 July 2008 - 07:35 PM

From what I understand Tricolor photography is the reproduction of an image by photographing a red, green, and blue channel separately.It is similar to making the tri-color separations of negative for archival purposes as far as I can tell.

http://www.oldandsol...graphy-13.shtml


some info there it seems. I googled 'round for a bit.
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#3 John Sprung

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Posted 22 July 2008 - 12:39 PM

Pretty much everything from three strip technicolor onward is trichromatic -- using three primaries like our eyes do. Earlier two color processes reproduced something that looked more like colorblind vision.




-- J.S.
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#4 anthony le grand

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Posted 23 July 2008 - 03:26 PM

Thanks for your answers!

So it's a way to separate the 3 colors channels in the camera to obtain particular effects? Do you know how can we do that?
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#5 Adrian Sierkowski

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Posted 23 July 2008 - 03:40 PM

From wikipedia:

The production of color films had decreased dramatically by 1932, when Technicolor unveiled its first three-color process in an attempt to entice the movie studios. Light passed through the lens and was then divided 50-50 by a beam splitting prism block. The green aspect of the scene was recorded through a filter on an orthochromatically sensitized film strip, while the light behind a magenta filter was further broken down by a bipack of a film strip panchromatically sensitized for red and a non-sensitized for blue light. The blue record film bore a red gelatin filter layer. This process accurately reproduced the full color spectrum and optically printed using a dye-transfer process in cyan, magenta and yellow.


Not the only way to do it, but they all require beam-splitting prisms as far as I know.


http://en.wikipedia....rip_Technicolor
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#6 John Sprung

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Posted 23 July 2008 - 03:55 PM

Not the only way to do it, but they all require beam-splitting prisms as far as I know.

No, all the current Kodak and Fuji color films are trichromatic, and have been since roughly WWII. They do it with three layers of emulsion. Trichromatic merely means that they use three primary colors.




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#7 Adrian Sierkowski

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Posted 23 July 2008 - 03:56 PM

Ok, quite true you got me there. I was referring more so to the process of shooting it on 3 strips of b/w film. a'la the older technicolor method. But, yes, color neg stock is separated into layers with dye masks.
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#8 anthony le grand

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Posted 23 July 2008 - 04:32 PM

Adrian, it's exactly what I was looking for. I'm conscious that it was a stupid question cause trichromatic means literally 3 colours but I was just looking for how they could be separated on 3 different strips. Things are clearer now.
Thanks!
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#9 Adrian Sierkowski

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Posted 23 July 2008 - 04:36 PM

Anytime.

Also, they did something similar to this on The 300, by using 3 cameras through a prism, I believe with 3 different focal lengths for some special effects shots. It wasn't trichromatic photography, but allowed all 3 cameras to frame the same even. So rigs for this type of stuff are around. But, you'd need 3 cameras and 3 of the exact same lenses. . .not exactly cheap.
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#10 Matt Butler

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Posted 24 July 2008 - 06:17 AM

There is another more limited variation of what I would call Tricolour photography where you expose the same piece of colour neg sequentially through a red,blue and green filter.
After each pass the lens is capped and the film rewound to the start of the shot, resulting in multi exposing three times - once obviously for each filter.
It is OK for locked-off, controlled situations, but live-action/talent shots would give a coloured ghosting fx.

A tricolour short (4.5MB) I photographed a lifetime ago is at this link: www.vimeo.com/1399698
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