Quote:
Originally Posted by Tomcomm
Wayne, thanks for the reply. I reran the 27in Sony by brightening the white bar. It was way too dark before which caused the red bar to saturate and as you said, "wash-out". The new results:
21in FBA.……………Red contaminated with 5.6% green and 8.2% blue
13in Sony……………Red contaminated with 12.6% green and 6.3% blue
27in Sony……………Red contaminated with 29.2% green and 21.3% blue
Somewhat less contaminated but still way orangish red compared to the Sony pro and the 21CT55 with 21FBP22A. The stated 255,0,0 RGB was "ideal" with no hardware limitations. I believe this simple and cheap method of relative phosphor comparisons can be quite useful when comparing the original NTSC rated crts eg 15GP22 and 21AXP22 with the gray screen 21FBP22A. All I need is optimally setup color bar screenshots of the original GP/AXPs. I don't have much hope for a live eyeball shootout that includes the gray screen 21FBP22A, certainly not one I may witness.
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This is still a little suspicious. Getting purer colors when the drive is turned up could indicate that the black level is a little high or there are reflections of room light. This would be a valid test of how the tube is set up and viewed, but not necessarily the characteristics of the red phosphor color alone. To get the comparison of the pure phosphor colors you need to do two things:
1) take the picture in a completely dark room, making sure there are no reflections (like from your shirt)
2) turn up the color control and adjust the tint if necessary to make sure only the red beam is on and the other two beams are completely cut off.
2b) Since the color demodulator may include color corrections that deliberately make the primary bars impure, you may need to readjust the tint individually for each primary color if you want to measure the green and blue also.