Quote:
Originally Posted by EdKozk2
Hi Bob,
I recall reading in some old literature that the chemical elements for the P4 phosphor were changed in the 50's. The newer 7JP4 like I bought in 1974 looks more gray/white. I even noticed this on a 5BP4 I bought from the ETF a few years ago.
Ed
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Every major manufacturer could (and some did) vary powered phosphor color... unpowered phosphor color can be as much a function of runtime as manufacturing process. If you have encountered a round tube that sat behind a square mask and was set up for minimal overscan there will be a browned center square and a blue outer ring.