Two-color Technicolor and black

Technically-oriented discussion of classic films on everything from 35mm to Blu-Ray
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Lincoln Spector

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Two-color Technicolor and black

PostMon Mar 13, 2017 7:00 pm

Last Saturday, I watched The King of Jazz at the Pacific Film Archive. It's a strange 1930 musical starring Paul Whiteman. The film was shot in 2-color Technicolor, and I saw it off a new, 4K DCP.

But as I watched it, I began to wonder about blacks--hair, tuxedos, etc--in the image. How did 2-color systems filter out all three colors to get a decent black.

As I understand it (and please correct me if I'm wrong), 3-color prints have three dye layers. The cyan dye suppresses red; the magenta dye suppresses green, and the yellow dye suppresses blue. You get black by sufficiently suppressing with all three dyes.

But with 2-color systems, the cyan suppresses red and the magenta suppresses green, but nothing suppresses the blue. Wouldn't black parts of the screen look blue?

Lincoln
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Richard P. May

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Re: Two-color Technicolor and black

PostTue Mar 14, 2017 8:52 am

I'm not sure of this, but if two-color printing was the same as early three-color, there was a black and white image printed first, then the dyes on top of that. This increased density above what the dyes of the time were capable. Beginning in the mid-1940s the dyes were improved, and this b&w image (called the key image) was eliminated.
The magenta negative was used to create this layer.
If this was also true for the two-color dye transfer printing, I suppose the red negative would have been used to create the key image, as it would be the closest in tonal accuracy to the original object.
Dick May
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Mike Gebert

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Re: Two-color Technicolor and black

PostTue Mar 14, 2017 9:32 am

Here's a film from George Eastman House that shows a number of examples of original two-color prints. I would say that true black is less what you see than a dark brown.

“Sentimentality is when it doesn't come off—when it does, you get a true expression of life's sorrows.” —Alain-Fournier
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All Darc

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Re: Two-color Technicolor and black

PostTue Mar 14, 2017 7:20 pm

The advanced fadded semented prints (system 1 I believe) in theory could be restored to full original colors. In theory...

Well, I do not refer about digital new ways, but find out a way to Split the "sandwich". Let's supose someone find out a way to separete both layers (prints glued together) and scan it individually. Voilá...

A restorer once told that in Bologna they create a way to separate the emulsion from the film base. If was possible to separate both emulsion of a semented print, could be possible to restore the colors of a complete fadded (dye fade) print.


About density and dyes blocks a given color...
Well, look this image bellow, and see in the "leaked frame" edges that the dye it's not exactly magenta, but much more close to pure red. So it blocks more blue.
The cyan dye it's more close to cyan than green, but it's not exactly pure cyan and so it would not allow so much blue go on as the pure cyan would..

Image
Keep thinking...

Image
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Lincoln Spector

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Re: Two-color Technicolor and black

PostWed Mar 15, 2017 9:11 am

Thanks.

I had no idea that the cemented prints used red and green dyes. I'd assumed they used cyan and magenta. That would block out more of the blue.

I wonder when they switched to the subtractive primaries? When they switched to dye transfer, or when they switched to 3-strip.

Lincoln
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All Darc

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Re: Two-color Technicolor and black

PostWed Mar 15, 2017 11:06 am

Technicolor System 2 was already subtractive. Technicolor aditive color system used no dyes but projected 2 frames at once using color filters.
The frame examples I showed you was subtractive, but manytimes the magenta dye was more close to red than magenta.
Since it have only two color channels it could have such variations, while a 3 color system would really require pure magenta, cyan and yellow.

Learn more here: http://www.widescreenmuseum.com/oldcolo ... color1.htm

Another color system, cinecolor 2 color system was interesting, it keep evolving, and for cartoons, like from Max Fleischer, they could change not only the color filters used in the camera, but change the dyes used to made prints, and so they could give priority to some green or to some blue.

Image

Image

For movies cinecolor also improved, like in this movie. in screen capture 2 you almost see something that resambles blue and gree, at same time.

http://www.blu-ray.com/movies/The-Carib ... creenshots

Image



Lincoln Spector wrote:Thanks.

I had no idea that the cemented prints used red and green dyes. I'd assumed they used cyan and magenta. That would block out more of the blue.

I wonder when they switched to the subtractive primaries? When they switched to dye transfer, or when they switched to 3-strip.

Lincoln
Keep thinking...

Image
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Allon

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Re: Two-color Technicolor and black

PostMon May 08, 2017 7:31 pm

Black parts would not be pure on a film print unlike the dcp you saw. There is no "neutral densities" in 2 color technicolor film. Can't be done without it being tinted. But digital color correcting can do so much more. The King of Jazz looked pleasing to the eye but the digital version was visually inaccurate compared to a 2 color film print.
YMMV
Allon

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