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  #16  
Old 12-03-2010, 08:09 PM
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It's worth pointing out that the networks here in the USA used different hardware systems, as well... the CBS system was particularly notorious for having a somewhat "pastel" color palette, particularly in comparison to NBC.

- Kevin
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  #17  
Old 12-03-2010, 11:38 PM
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Years ago I was adjusting the color balance on a modern CRT computer monitor.

I had made a wallpaper in MS Paint of a color bar test pattern mimicking the NTSC pattern.

I found that when I turned the green and blue channels to zero, that the red no longer looked red, rather an orange with a sepia cast.

Since then, I've wondered if CRT color TV sets abt computer monitors was delivered with a very blue color balance (9300K versus about 5500K of daylight illumination) because the "orange-sepia" yttrium red phosphor looks red against such a bluish image (comments most welcome).
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Old 12-04-2010, 08:20 AM
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watch the brightness level

Quote:
Originally Posted by kx250rider View Post
The early CRTs had sulfide phosphor, which caused the greens and reds to be much deeper. After the mid-50s, they went to rare earth phosphors, which made less-deep greens, and orangish reds.

Charles
With the sulfide tubes you really couldn't turn the brightness up all the way or the reds would appear orangey. The rare earth phosphers resolved a lot of those problems, but all the sets I see on this site have the contrast cranked and that was never the way to achieve the best possible picture.

If you look at some of the new flat panel with the THX settings they really cut back the contrast and brightness to take advantage of the visual effects of the film, the same could be said of the older color sets if you back down the contrast you really start seeing the beauty of the product.
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  #19  
Old 12-04-2010, 06:22 PM
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Quote:
Originally Posted by oldtvman View Post
With the sulfide tubes you really couldn't turn the brightness up all the way or the reds would appear orangey. The rare earth phosphers resolved a lot of those problems, but all the sets I see on this site have the contrast cranked and that was never the way to achieve the best possible picture.

If you look at some of the new flat panel with the THX settings they really cut back the contrast and brightness to take advantage of the visual effects of the film, the same could be said of the older color sets if you back down the contrast you really start seeing the beauty of the product.
Yes, the sulfide red actually shifted toward orange at high current density. The rare earth red doesn't shift, but the sulfide green and blue can saturate at high current, which can be a problem in rear-projection sets.
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  #20  
Old 12-04-2010, 06:43 PM
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Quote:
Originally Posted by Robert Grant View Post
Years ago I was adjusting the color balance on a modern CRT computer monitor.

I had made a wallpaper in MS Paint of a color bar test pattern mimicking the NTSC pattern.

I found that when I turned the green and blue channels to zero, that the red no longer looked red, rather an orange with a sepia cast.

Since then, I've wondered if CRT color TV sets abt computer monitors was delivered with a very blue color balance (9300K versus about 5500K of daylight illumination) because the "orange-sepia" yttrium red phosphor looks red against such a bluish image (comments most welcome).
Some of that is true. However, the "9300K + 27MPCD" is just a sneaky way of saying the picture doesn't have enough red drive to make D65 (6500K, the standard for TV white point [or the original illuminant "C," which was slightly magenta compared to D65]). Besides the increase in R-Y gain to make up for the sulfide yellowish green, running at 9300 made flesh tones look unacceptably cyan unless the color gain was turned up even more. The original reason for this was to keep the beam current ratios somewhat reasonable to prevent red blooming on the highlights; however, it was a disaster for color rendering and for the stability of color with transmission variations. Zenith at one time (after rare-earth reds came into use) used a different white point, between 9300 and D65, which still gave some additional contrast between white and red and reasonable current ratios, but improved the apparent stability of color rendition. Best color, of course, is with white point set to D65 so it matches studio use, but then the current ratios may actually require more current in green than red, depending on the phosphor efficiencies in a particular tube model.

Unequal currents are always a problem due to possible blooming of the spot size of the most heavily driven gun on highlights, putting a color halo around small bright details. Before rare-earth reds, the 9300K was a compromise to get acceptable beam ratios. After rare earth reds appeared, 9300 was still used in some sets apparently because people were used to it, even though it wasn't necessary. Mitsubishi used a very cyan white point in their rear projos for a long time, and I personally think whoever made that decision should have been fired and replaced with someone who had a clue.
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