Purple CRT?

[kbmuri]

I saw this at the ETF convention over the weekend. If it had been anywhere else I'd have thought it was a practical joke. The CRT phosphors were dark purple/plum. Very strange. There were two sets like it, and a third (I believe) that was missing the tube. The commentary sheets above each claimed this type of CRT was briefly popular in Great Britain. Any AKers out there own one? Working? I'd love to see it in action.

[wa2ise]

Maybe that set with the purple screen has a replacement green phosper CRT and has a purple colored filter in front to make it look less green (at the expense of brightness)?

Back in the 80's, GE had sets with CRTs that would look to be dark blue when the sets were turned off.

[Steve K]

I believe that those CRTs have the standard white phosphor but have a purple filter in front. Sort of like the Hoffman Easy Vision idea.

Steve

[kbmuri]

Hmm. I won't contradict you guys, 'cause I just don't know. But it didn't strike me as a filter. The phoshor surface looked flat purple, and not bright at all like regular P4 phosphor would look behind candy-colored glass. I guess I should have taken a better photo. I had hoped an expert would chime in and describe the chemistry/physics of it. But perhaps there isn't any. It was a curiosity to me. I guess it will remain so...

[fujifrontier]

I've seen vintage small sony TVs with pinkish screens.

[Steve McVoy]

These sets all use normal P4 CRTs. It is the safety glass (plastic) that makes them purple.

[Sandy G]

Yeah, I've got a Sony 5-303W w/a pinkish screen..I remember years & years ago hearing that when the screen on one of them got that pinkish "cast" to it, the CRT was about shot...The one I have that's pinkish SEEMS to have an OK picture though, so who knows ?

[bgadow]

I have one of those little Hotpoint (GE) 9" sets from the late 50s. The crt has a decided purple cast, though not nearly so strong as the British sets. It's in storage now; I can't recall if it is the safety glass or the crt with that tint.

[fujifrontier]

the question is why though

[yagosaga]

Originally Posted by Steve K

I believe that those CRTs have the standard white phosphor but have a purple filter in front.

Steve is correct. I own a PYE LV30 with such a purple filter in front:

http://bs.cyty.com/menschen/e-etzold...e/img/LV30.jpg

The CRT is a common MW22-17 (with an ion burn in the middle of the screen). This purple filter was used to suppress reflections on the screen and to generate more contrast.

Eckhard

[kbmuri]

Thanks all. I'm convinced it's a filter. I recommend anyone going to the museum to have a look though. It's a very "distinct" look.

- k