I have a few Vintage TVs from 70s & early 80s. I notice that compared to my newer sets the color on older ones gets a kinda funky purple / green thing going on.
Are the newer set that much better or is there something that happens to these older sets after a while?
Thanks in advance if you can solve this mystery for me!
A 30 year old TV is likely to need some work before it performs like it should. Assuming the CRT is good, a TV from the 70's is capable of providing a picture almost as good as the best modern TVs. Andy Cuffe
snipped-for-privacy@psu.edu
Color TVs were actually perfected back in the 50's, with RCA having the best color until the 70's. My Dad had a 59 Admiral (RCA CTC11) that had the most beautifully saturated colors, and he used it until 1978 when the tube suddenly went soft.
You didn't mention what kind of TVs you are using in your comparison, but cheap TVs give you cheap performance, be it color quality, brightness, focus, geometry, etc. There would be no reason why a quality TV of the 70s and 80s wouldn't have accurate color.
John
Due to the sensitivities of the phosphors in a CRT, the red gun is the hardest driven so tends to lose output first. The result is a green hue. Indeed some early Trinitron sets had an external green gain control to make adjustment easy.
In the '70s, some makers changed to phosphors that gave a brighter picture but an orange rather than a true red. And these could never give decent flesh tones.
It was earlier than that. They changed from a magnesium fluorogermanate phosphor to a yttrium vanadate. The fluorogermanate did produce a very nice red, but brightness was far too low compared to modern CRTs. The same phosphors were used on coated mercury vapor lamps, the former is denoted /C while the latter, which came out in the mid 60's is /DX.
In the UK we didn't have colour TV in the mid '60s. ;-) But the first generation sets here with 19 and 25" shadow mask tubes used the original NTSC phosphors. The rot started with PIL types.
One is a Big Squarish Sony Trinitron and the other is a retro space-age roundish Toshiba Portable.
I have played around with the tint, since they both seem to have the same sort of problem I was wondering if it is something common.
It's almost like the Green and Purple are too saturated or that there is a
3rd color that is too weak.
It is - see my earlier reply. You need to do a grey scale balance. If you Google you should find details of what this involves.
Don't you read replies to this thread?
The standard for colour TV in North America is NTSC (National Television Standards Committee - this was the body set up in the 1950s to determine the best way to encode colour information into the TV signal without degrading the picture on a monochrome set). The system works well within a studio but suffers from severe colour changes due to phase distortions during transmission. I have heard it referred to as Never Twice the Same Colour! Later developments overcame this shortcoming to some extent. You may simply be looking at old TV sets where this problem was prevalent.
The European System, PAL (Phase Alternating Line) overcame the problem by alternating the phase of the reference colour subcarrier on successive lines.
Regards,
Don Reid England
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