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I agree with what you say about using instrumentation to set grey scale. Actually, I have never had the advantage of being a TV repair technician. For most of my work life I was an editor of one type or another. But I’ve also had opportunity to make a living troubleshooting to component level and have spent a few years working with instrumentation including initial power-on thru final calibration. All this is in support of my first sentence.
I’m going to check eBay; perhaps a reasonably priced colorimeter still in acceptable calibration will turn up.
Some things I’ve grown to acknowledge and appreciate recently are issues that effect stability of this restored Merrill. My feeling is that it’s a result of the original design rather than some artifact of age or the restoration process. In discussing this with John Folsom, who of course is a premier collector of 15-in. vintage color, it seems that most vintage sets are fickle, but the Westinghouse H840CK15 is far more stable than the CT-100, particularly in the area of high-voltage regulation, which I find, in the CT-100, is apparently an issue in an attempt to achieve brightness suitable for a desired, wide, grey scale.
Another area that’s been challenging when adjusting the matrix is to achieve a toned-down green component in the color bar display. It’s well known and fully appreciated that the red phosphor in a 15GP22 is by far the least efficient. I expect to work more on these challenges this weekend, but perhaps there’s just not enough latitude in the red to overcome the brightness and more importantly perhaps, the very wide green gamut, when adjusting grey scale (as you say, 20IRE to 100IRE) before trying to get eyeball-perfect color bars.
As I said, never had hands-on TV repair experience or did I ever work in broadcast video, so much of this detail stuff is new to me. Add to that the fact I’m an old guy….
Appreciate all the comments and suggestions received along the way. In particular, Old_TV_Nut with all his envious TV-engineering experience who kindly nudges me in the right direction now and then.
Have attached a shot taken this morning of simultaneous ATSC-NTSC broadcasts. The two ends of the engineering spectrum match fairly well in this shot, but I’ll admit to toning back the HD set in brightness and contrast a bit.
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