On Tuesday, 7 August 2018 15:00:26 UTC+1, dennis@home wrote:
doesn't that depend on what you mean or rather they mean by monochrome.
perhaps they are just trying to copy apples night mode.
which goes red .
perhaps if anyone has a google phone they could let us know.
If they alter it to warm white colour temperature that will probably be
good enough to avoid the worst effects of blue light on the brain.
Plenty of star chart apps have a night mode where "monochrome" actually
means various intensities of red which doesn't affect night vision.
The value of red torches to astronomers is well known. I am less
convinced by the currently fashionable "blue stops you sleeping"
argument. Although deliberately "warming" the screen colours both
simulates the colour of twilight and opens the iris, so could provide
genuine physiological triggers for sleep.
On Tuesday, 7 August 2018 15:40:05 UTC+1, newshound wrote:
But I;ve seen test that prove it or rather support it.
The use of proper SAD lighting uses blue.
Someone run an expeiment in a pub on differnt night they used differnt colour lighting. Asking peole what they thought the efect would be and it was that red light would make you feel more thirty as you'd think you were hotter.
But what they foudn was peole stayed much longer upto an hour if the light was blue, blue light does have more energy than the same amount of red light.
but as people are differnt a friend of mione last night got up at 11:30am yesterday while I was up at 7:30am By 1am he was falling asleep I was checking facxebook, we had the same lighting.
Maybe yuo should try it on yourself.
and doing the oppersite should.....
The problem needs to be licked for us blind folk who get visual
disturbances. I can be dazzled in the night merely by noise from the
defunct retina or optic nerve, a kind of visual tinnitus.
Its one of those problems we have that no doctors has ever seen, as for
obvious reasons, only we see it. I was almost arrested once for having
pupils that dilate and go back to normal for no apparent reason, the guy
thought I had taken a dodgy substance you see!
I of course was unaware of the pupil issue, but thinking about it if the
brain thinks you are dazzled it would be a reflex action.
This newsgroup posting comes to you directly from...
On Tue, 07 Aug 2018 21:20:15 +0100, Tim Lamb wrote:
It was just the use of a very long persistence phosphor required for
oscilloscope CRTs which then found its way into the early PPI radar
display tubes. I think the fact that the phosphor chosen happened to be
green in colour was secondary to its more desirable property of long
There may have been other colours of long persistence phosphors
available but I suspect the green one was probably deemed the best
overall choice at that time, over 70 years ago (at least by British and
American manufacturers - the Germans may have chosen another colour of
long persistence phosphor but that doesn't address Brian's question).
The problem was that although pure green and red were easy to do the
pure blue phosphors proved very elusive and was pale blue due to yellow
impurities in the light produced. This was fixed by adding a trace of
neodymium to the front screen to knock out the unwanted yellow.
Initially they over corrected leading to cartoon like real world colours
as opposed to the pastel shades of the earlier "colour" sets. Early
colour TV sets tended to go wrong a lot - and had a rather dangerous
Xray emitting EHT stack at the back. Made hiring one cost effective
unless you could do your own repairs.
On Wednesday, 8 August 2018 09:30:36 UTC+1, Martin Brown wrote:
It's unfortunate that I can't remember exactly what the primaries were on t
he sets I'm talking about. I vaguely remember the green being a yellow-gree
n. The end result was a much warmer toned picture that surprisingly looked
ok on most scenes, but now & then looked quite off. Sat next to the usual R
GB displaying a test card showed how off they were - some of the card colou
rs just weren't the right colour at all.
I was thinking much further back... early days of radiation
I'll see if I can find where I read it. Ah! I have it:-) Alfred Romer,
The restless atom.
Cathode rays, if close enough, lit up the glass which was green for
English lime glass and blue for the lead glass of the Germans.
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