Quote:
Originally Posted by old_tv_nut
By the way, when you measure a tube, you get the operational color, not the pure phosphor color, because any imperfections in the color purity settings, light scattering, electron scattering, etc. are all included.
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Armed with old instrumentation experience [as a kid I worked for an instrument manufacturer for some years doing initial power-up, troubleshooting, test, and calibration] and when the Spyder calorimeter became known a few years ago, I made some measurements of a near-pristine 15GP22. I particularly considered purity, ambient light, and repeatability when making the 'operational color' measurements.
For example, I took measurements at screen locations that exhibited the best purity. All readings were made with a dark cloth over the set.
Results did support the 15GP22's reputation for gamut. Only the green fell a bit short of the 0.21, 0.71 1953 NTSC standard. But not by much.
At the time, John Folsom platted the results on a graphic that included the 1951 CBS and 1953 NTSC, and I believe the sRGB standards. As I am in SC visiting relatives after the ETF convention, I unfortunately do not have access to the graphic at this time.
For me, this was one step in the quest to reproduce what one would have seen in the early days of color television. Wayne Bretl has demonstrated mathematically that the TK-41 was capable of generating a 1953 NTSC compliant image. Now if we can only get Mrs. Astaire to allow us a DVD of her husband's restored October '58 special, we could demo the real thing at the next ETF convention...
Pete