O
Owain
Guest
Dave Plowman (News) wrote:
Owain
Of which species?
Owain
P
Phil Hobbs
Guest
Dave Liquorice wrote:
Cheers
Phil Hobbs
http://www.youtube.com/watch?v=_Nbkbss7i5sOn Mon, 11 May 2009 12:20:56 +0100, Tim S wrote:
I'll have an LED TV when they become cheap/big enough
Big isn't a problem, is a 12.8m x 7.2m 1280 x 720p screen big enough?
Weight and cost might be though. B-)
http://www.adi.tv/rental/products-i100.html
You could make some kids' day with that, the way these folks did:
Cheers
Phil Hobbs
A
Arfa Daily
Guest
"Meat Plow" <meat@petitmorte.net> wrote in message
news:2q8gov.rv1.19.10@news.alt.net...
savvy about this sort of thing than you give them credit for ...
Arfa
news:2q8gov.rv1.19.10@news.alt.net...
Perhaps, but I think that the current generation might just be rather more
savvy about this sort of thing than you give them credit for ...
Arfa
L
Leonard Caillouet
Guest
"Dave Plowman (News)" <dave@davenoise.co.uk> wrote in message
news:505a2c6f73dave@davenoise.co.uk...
The reason that one might want to have more segment with more colors, as is
done in many DLP color wheels (such as the Mitsubishis that use 6 colors,
RGBCY&M) is that you can get spectral performance that is more efficient use
of the available light source. You have to change your decoding to
accommodate the relative spectral differences to take proper advantage of
the new colors, however, and this may result in some improvement in some
areas and poorer performance in others. The Mitsubishis seem to have this
tweaked pretty well after several generations of doing so.
While it is true that you can get any color within the gamut defined by
three primaries, RG&B, with combinations of those three, the amount of each
required for a given color will vary with the spectrum available. The
bottom line is that the performance depends on the execution of the system
as much as the particulars of the spectrum of the available sources and the
filters being used.
You simply cannot assume that all colors are going to be correctly
reproduced without knowing more about the spectrum and the decoding matrix
and/or LUTs.
Leonard
news:505a2c6f73dave@davenoise.co.uk...
The reason that one might want to have more segment with more colors, as is
done in many DLP color wheels (such as the Mitsubishis that use 6 colors,
RGBCY&M) is that you can get spectral performance that is more efficient use
of the available light source. You have to change your decoding to
accommodate the relative spectral differences to take proper advantage of
the new colors, however, and this may result in some improvement in some
areas and poorer performance in others. The Mitsubishis seem to have this
tweaked pretty well after several generations of doing so.
While it is true that you can get any color within the gamut defined by
three primaries, RG&B, with combinations of those three, the amount of each
required for a given color will vary with the spectrum available. The
bottom line is that the performance depends on the execution of the system
as much as the particulars of the spectrum of the available sources and the
filters being used.
You simply cannot assume that all colors are going to be correctly
reproduced without knowing more about the spectrum and the decoding matrix
and/or LUTs.
Leonard
L
Leonard Caillouet
Guest
"Arfa Daily" <arfa.daily@ntlworld.com> wrote in message
news:jsaOl.30044$Ku5.27475@newsfe10.ams2...
people, but you simply cannot assume that either technology will be better
or worse. It depends on many factors. Assumptions usually bite you in the
ass. You should know that by now, Arfa.
Leonard
news:jsaOl.30044$Ku5.27475@newsfe10.ams2...
Looking perfectly fine is a very subjective assessment. It is fine for most
people, but you simply cannot assume that either technology will be better
or worse. It depends on many factors. Assumptions usually bite you in the
ass. You should know that by now, Arfa.
Leonard
A
Andy Champ
Guest
ZZactly@aol.com wrote:
It's from Biology, not physics; RGB are the peak sensitivities of the
three colour receptors in the most common human retina. We're so poor
at telling them apart that a red-green mix looks pretty much like some
kind of yellow. (Narrow spectrum lamps are fine for TV, but they can
make your wallpaper look a bit odd, which is one of the CFL problems)
Most common sort? Well, colour blindness is an obvious case. But
apparently a few women have 4-colour vision.
And for true colour accuracy (though without speed or much resolution)
look at the Mantis Shrimp. IIRC it has sensors for polarisation and a
complete spectrometer build into its eye.
Andy
You may not care, but I'm going to tell you anyway
It's from Biology, not physics; RGB are the peak sensitivities of the
three colour receptors in the most common human retina. We're so poor
at telling them apart that a red-green mix looks pretty much like some
kind of yellow. (Narrow spectrum lamps are fine for TV, but they can
make your wallpaper look a bit odd, which is one of the CFL problems)
Most common sort? Well, colour blindness is an obvious case. But
apparently a few women have 4-colour vision.
And for true colour accuracy (though without speed or much resolution)
look at the Mantis Shrimp. IIRC it has sensors for polarisation and a
complete spectrometer build into its eye.
Andy
T
Tim S
Guest
Andy Champ coughed up some electrons that declared:
Just out of interest, what's the 4th colour?ZZactly@aol.com wrote:
Red green and blue are defined scientifically as primary colors. I
don't know where those standards came from, nor do I care
You may not care, but I'm going to tell you anyway
It's from Biology, not physics; RGB are the peak sensitivities of the
three colour receptors in the most common human retina. We're so poor
at telling them apart that a red-green mix looks pretty much like some
kind of yellow. (Narrow spectrum lamps are fine for TV, but they can
make your wallpaper look a bit odd, which is one of the CFL problems)
Most common sort? Well, colour blindness is an obvious case. But
apparently a few women have 4-colour vision.
I'm getting that "Geordie" moment
D
Dave Plowman (News)
Guest
In article <jsaOl.30044$Ku5.27475@newsfe10.ams2>,
Arfa Daily <arfa.daily@ntlworld.com> wrote:
cameras. Three or four tubes - usually Plumblicons. Which would show
Magenta as bright green, etc. And of course many CRT sets didn't use the
best phosphors - more concerned with how bright they'd go.
better but still don't give as good a light quality as the best
fluorescents.
unless it's Des O'Connor's makeup. Wasn't talking about a quick glance.
actually seen one. Perhaps they are as good as claimed. Cynical me doubts
it.
Thing is for domestic light my preference is halogen, quality wise.
Expensive fluorescent tubes can match that well enough. CFLs not. Nor any
LED I've yet tried.
--
*The severity of the itch is proportional to the reach *
Dave Plowman dave@davenoise.co.uk London SW
To e-mail, change noise into sound.
Arfa Daily <arfa.daily@ntlworld.com> wrote:
Think that was more to do with the deficiencies of the then tube colour
cameras. Three or four tubes - usually Plumblicons. Which would show
Magenta as bright green, etc. And of course many CRT sets didn't use the
best phosphors - more concerned with how bright they'd go.
Heh heh - advertising? I play with LEDs quite a bit, and they are getting
better but still don't give as good a light quality as the best
fluorescents.
Flesh tones contain a vast range of colour shades even on the one face -
unless it's Des O'Connor's makeup. Wasn't talking about a quick glance.
Well yes and I agree. They're pushing them on TV too. But I haven't
actually seen one. Perhaps they are as good as claimed. Cynical me doubts
it.
More to the point to compare with HID in cars?
Thing is for domestic light my preference is halogen, quality wise.
Expensive fluorescent tubes can match that well enough. CFLs not. Nor any
LED I've yet tried.
--
*The severity of the itch is proportional to the reach *
Dave Plowman dave@davenoise.co.uk London SW
To e-mail, change noise into sound.
A
Arfa Daily
Guest
"Dave Plowman (News)" <dave@davenoise.co.uk> wrote in message
news:505a853dabdave@davenoise.co.uk...
Well no, I don't think it was. Take a look at
http://www.yorku.ca/eye/nonspect.htm
which explains pretty much what I remember. The example of brown is quite a
good one, even with it shown in isolation - i.e. with no surrounding colours
and no visual cues. As an example of that, if it was a picture of a turd,
your brain might very reasonably *expect* it to be brown ...
No, I wasn't either. I have two friends who both own top end digital SLRs,
one because he is a professional photographer, and the other because he is a
very keen hobbyist. I have looked at the viewfinder images closely on both
of these cameras, and the rendition of flesh tones in all the varieties is
excellent, and the professional of the two has commented to me how good he
thinks the viewfinder is at colour rendition under all light levels (input
that is, not viewing conditions).
Contrary to what you believe about the phosphors on CRTs, I don't believe
that there has been any significant change in their colour rendition
capabilities since the earliest delta gun tubes in the uk, which I worked
with from about 1970. Even back then, if you put in the time to ensure that
the decoder was correctly adjusted, and the CRT colour balance and tracking
was correctly set, they had the ability to render flesh tones superbly. In
fact this criterion was the main one we used to subjectively evaluate the
performance of a set, and was one of the main reasons for the broadcasters
using a little girl, whose skin was 'natural' and had no makeup, on test
card F. In contrast (no pun intended !) I think that the colour rendition of
most LCD TV sets - particularly in the case of flesh tones, is nothing less
than dreadful. So if LED backlighting improves on this - and the case of the
camera viewfinder images would tend to support this view - then that will be
good.
efficiencies of a 'standard' 50 watt halogen headlamp bulb, which we all
have a pretty fair idea of the brightness of, and the same thing in a LED
version, which is likely to be at least as bright, if not brighter,
otherwise there would be no point in the manufacturers trying to use them.
If the LED equivalent power consumption was say 10 watts, then we would know
that LED backlighting of LCDs was likely going to be more efficient than
CCFL backlighting, which we already know consumes around 100 watts to light
a 32" screen. If on the other hand the LED equivalent power was 50 or 75
watts, then we would know that it was going to be no better, and possibly
worse.
Agreed all four points
Arfa
news:505a853dabdave@davenoise.co.uk...
Well no, I don't think it was. Take a look at
http://www.yorku.ca/eye/nonspect.htm
which explains pretty much what I remember. The example of brown is quite a
good one, even with it shown in isolation - i.e. with no surrounding colours
and no visual cues. As an example of that, if it was a picture of a turd,
your brain might very reasonably *expect* it to be brown ...
No, I wasn't either. I have two friends who both own top end digital SLRs,
one because he is a professional photographer, and the other because he is a
very keen hobbyist. I have looked at the viewfinder images closely on both
of these cameras, and the rendition of flesh tones in all the varieties is
excellent, and the professional of the two has commented to me how good he
thinks the viewfinder is at colour rendition under all light levels (input
that is, not viewing conditions).
Contrary to what you believe about the phosphors on CRTs, I don't believe
that there has been any significant change in their colour rendition
capabilities since the earliest delta gun tubes in the uk, which I worked
with from about 1970. Even back then, if you put in the time to ensure that
the decoder was correctly adjusted, and the CRT colour balance and tracking
was correctly set, they had the ability to render flesh tones superbly. In
fact this criterion was the main one we used to subjectively evaluate the
performance of a set, and was one of the main reasons for the broadcasters
using a little girl, whose skin was 'natural' and had no makeup, on test
card F. In contrast (no pun intended !) I think that the colour rendition of
most LCD TV sets - particularly in the case of flesh tones, is nothing less
than dreadful. So if LED backlighting improves on this - and the case of the
camera viewfinder images would tend to support this view - then that will be
good.
Why particularly ? I was just trying to draw a comparison as to the relative
efficiencies of a 'standard' 50 watt halogen headlamp bulb, which we all
have a pretty fair idea of the brightness of, and the same thing in a LED
version, which is likely to be at least as bright, if not brighter,
otherwise there would be no point in the manufacturers trying to use them.
If the LED equivalent power consumption was say 10 watts, then we would know
that LED backlighting of LCDs was likely going to be more efficient than
CCFL backlighting, which we already know consumes around 100 watts to light
a 32" screen. If on the other hand the LED equivalent power was 50 or 75
watts, then we would know that it was going to be no better, and possibly
worse.
Agreed all four points
Arfa
D
Dave Plowman (News)
Guest
In article <dFpOl.123771$A85.94314@newsfe03.ams2>, Arfa Daily
<arfa.daily@ntlworld.com> wrote:
correct NTSC phosphors. Which gave a pretty pure red. The rot really came
in with PIL tubes which used a very 'orange' red phosphor simply because
it allowed a brighter picture. And that had real implications to flesh
tones. Took many years before that was corrected.
--
*We have enough youth, how about a fountain of Smart?
Dave Plowman dave@davenoise.co.uk London SW
To e-mail, change noise into sound.
<arfa.daily@ntlworld.com> wrote:
Oh, but there was. The original delta gun shadow mask tubes used the
correct NTSC phosphors. Which gave a pretty pure red. The rot really came
in with PIL tubes which used a very 'orange' red phosphor simply because
it allowed a brighter picture. And that had real implications to flesh
tones. Took many years before that was corrected.
--
*We have enough youth, how about a fountain of Smart?
Dave Plowman dave@davenoise.co.uk London SW
To e-mail, change noise into sound.
A
Arfa Daily
Guest
"Dave Plowman (News)" <dave@davenoise.co.uk> wrote in message
news:505ab62302dave@davenoise.co.uk...
worse a picture, in terms of colour rendition, than deltas. Certainly, they
were an improvement in convergence and extremity focus - perhaps even
overall 'sharpness'. If the colour / output of the red phosphor did not
match the transmitted weighting factor for that colour, I would have thought
that this would have caused serious problems for rendering whites and greys
correctly, and would have had a significantly pronounced effect on the
ability of the tube to render subtleties such as flesh tones. An 'orangy'
red would have screwed about with the chromaticity diagram, and completely
altered the pallette of colours that the tube *could* produce from just
three primaries. It would be like taking a printer's pantone colour chart,
and redefining all the hues, wouldn't it ?
We had some pretty fussy customers back then with serious pots of money, and
I can't recall any colour accuracy issues ever arising - aside from one
particular customer who used to complain on a weekly basis that colours were
"bleeding through" (convergence issues !) and in the summer that there was
something wrong because the grass in front of the wicket on the cricket, was
yellow ...
Nor can I recall any mention of this either in the trade press, or at our
company's training school, which was recognised as being one of the best
that there was.
Anyway, going back to chromaticity diagrams, did you look at the link to an
explanation of 'non-spectral colours' to see what I was talking about,
outside of any differences which there may or may not have been with the
phosphor colours ?
Arfa
news:505ab62302dave@davenoise.co.uk...
Hmmm. I can't say that I remember slot mask / in line tubes producing any
worse a picture, in terms of colour rendition, than deltas. Certainly, they
were an improvement in convergence and extremity focus - perhaps even
overall 'sharpness'. If the colour / output of the red phosphor did not
match the transmitted weighting factor for that colour, I would have thought
that this would have caused serious problems for rendering whites and greys
correctly, and would have had a significantly pronounced effect on the
ability of the tube to render subtleties such as flesh tones. An 'orangy'
red would have screwed about with the chromaticity diagram, and completely
altered the pallette of colours that the tube *could* produce from just
three primaries. It would be like taking a printer's pantone colour chart,
and redefining all the hues, wouldn't it ?
We had some pretty fussy customers back then with serious pots of money, and
I can't recall any colour accuracy issues ever arising - aside from one
particular customer who used to complain on a weekly basis that colours were
"bleeding through" (convergence issues !) and in the summer that there was
something wrong because the grass in front of the wicket on the cricket, was
yellow ...
Nor can I recall any mention of this either in the trade press, or at our
company's training school, which was recognised as being one of the best
that there was.
Anyway, going back to chromaticity diagrams, did you look at the link to an
explanation of 'non-spectral colours' to see what I was talking about,
outside of any differences which there may or may not have been with the
phosphor colours ?
Arfa
D
dennis@home
Guest
"Arfa Daily" <arfa.daily@ntlworld.com> wrote in message
news:dFpOl.123771$A85.94314@newsfe03.ams2...
done with mirrors.
There are only a few that use electronic viewfinders and they are low end.
news:dFpOl.123771$A85.94314@newsfe03.ams2...
Top level digital SLRs don't use any electronics in the viewfinder, its all
done with mirrors.
There are only a few that use electronic viewfinders and they are low end.
W
William Sommerwerck
Guest
"Dave Plowman (News)" <dave@davenoise.co.uk> wrote in message
news:505ab62302dave@davenoise.co.uk...
original phosphors that were orangish, improving only with the rare-earth
phosphors of the early '60s. (I remember Sylvania's radio ads.)
In fact, I'm pretty certain that most of what's being posted about color TV
and color analysis/reproduction is utter bilge. But I don't have a
comprehensive understanding of this material (it's not easy), so I'm pretty
much keeping my mouth shut.
news:505ab62302dave@davenoise.co.uk...
I would almost bet my life that this is absolutely backwards -- it was the
original phosphors that were orangish, improving only with the rare-earth
phosphors of the early '60s. (I remember Sylvania's radio ads.)
In fact, I'm pretty certain that most of what's being posted about color TV
and color analysis/reproduction is utter bilge. But I don't have a
comprehensive understanding of this material (it's not easy), so I'm pretty
much keeping my mouth shut.
A
Arfa Daily
Guest
"dennis@home" <dennis@killspam.kicks-ass.net> wrote in message
news:gueb38$77d$1@news.datemas.de...
worth, so I wouldn't call that particularly low end, although I am sure
there are others more expensive. If they do not have an LCD panel on them to
at least review the pictures you have taken, without having to plug the
thing into a computer, that rather defeats the object of it being a portable
'digital' camera, doesn't it ? Even the 3 grand offering on this page has a
3" LCD
http://www.calumetphoto.co.uk/Digital%20Cameras/Digital%20SLR/Nikon/?cm_mmc=GoogleUK-_-DSLR-_-DSLR-_-Nikon%20SLR&utm_source=google&utm_medium=cpc
Perhaps I am not being quite accurate in calling it a "viewfinder". I accept
that the higher end cameras have a proper optical viewfinder operating on
the SLR mirror / prism system, but the LCD panel also serves as a
supplementary viewfinder, as well as a display medium for photos already
taken.
Arfa
news:gueb38$77d$1@news.datemas.de...
I'm pretty sure that one of them told me that his camera was over a grand's
worth, so I wouldn't call that particularly low end, although I am sure
there are others more expensive. If they do not have an LCD panel on them to
at least review the pictures you have taken, without having to plug the
thing into a computer, that rather defeats the object of it being a portable
'digital' camera, doesn't it ? Even the 3 grand offering on this page has a
3" LCD
http://www.calumetphoto.co.uk/Digital%20Cameras/Digital%20SLR/Nikon/?cm_mmc=GoogleUK-_-DSLR-_-DSLR-_-Nikon%20SLR&utm_source=google&utm_medium=cpc
Perhaps I am not being quite accurate in calling it a "viewfinder". I accept
that the higher end cameras have a proper optical viewfinder operating on
the SLR mirror / prism system, but the LCD panel also serves as a
supplementary viewfinder, as well as a display medium for photos already
taken.
Arfa
W
William Sommerwerck
Guest
Several DSLRs have live LCD viewing, which could be considered a viewfinder,
as it serves the same function. I recently purchased such a camera (though
not for that reason). I haven't checked skin tones, but the color rendition
is not obviously "off".
Perhaps I'll drag out my Macbeth color checker and compare under noon
daylight -- the next time we have any in Seattle.
One of the best uses for the LCD panel is to confirm the camera's
color-temperature setting. It's particularly useful when fine-tuning the
green-magenta axis under fluorescent light.
As I write this, I'm watching CNN on my cheap-but-good 32" Vizio. Most are
perhaps slightly "warmer" than they should be. Not having the original flesh
for comparison, I can't know for sure.
D
Dave Plowman (News)
Guest
In article <guef5m$6td$1@news.motzarella.org>,
William Sommerwerck <grizzledgeezer@comcast.net> wrote:
years after that.
although I'm on the sound side. But hear plenty from those who work on the
vision side of things. ;-) And it was certainly the case that Grade 1
picture monitors continued with delta gun tubes long after PIL were
introduced domestically - and stuck with the original NTSC phosphors. As
this was the standard the cameras were 'calibrated' to.
--
*Can fat people go skinny-dipping?
Dave Plowman dave@davenoise.co.uk London SW
To e-mail, change noise into sound.
William Sommerwerck <grizzledgeezer@comcast.net> wrote:
Colour TV didn't arrive in the UK 'till the late '60s. PIL tubes were some
years after that.
Quite a bit of what I'm saying comes from working in TV production -
although I'm on the sound side. But hear plenty from those who work on the
vision side of things. ;-) And it was certainly the case that Grade 1
picture monitors continued with delta gun tubes long after PIL were
introduced domestically - and stuck with the original NTSC phosphors. As
this was the standard the cameras were 'calibrated' to.
--
*Can fat people go skinny-dipping?
Dave Plowman dave@davenoise.co.uk London SW
To e-mail, change noise into sound.
A
Andy Dingley
Guest
On 12 May, 22:14, Tim S <t...@dionic.net> wrote:
The problem in describing it is that as language was written by people
who couldn't see it anyway, we simply don't have a word for it. I've
heard is described as being able to see a difference between "orangey
brown" and "browny orange" as distinct colours, rather than just
shades of mud.
Presumably this is why handbags and shoes come in colours like "taupe"
and "wombat's pouch", where no-one else has a clue what they mean.
Octarine of course!
The problem in describing it is that as language was written by people
who couldn't see it anyway, we simply don't have a word for it. I've
heard is described as being able to see a difference between "orangey
brown" and "browny orange" as distinct colours, rather than just
shades of mud.
Presumably this is why handbags and shoes come in colours like "taupe"
and "wombat's pouch", where no-one else has a clue what they mean.
W
William Sommerwerck
Guest
But there was no "original" NTSC red phosphor -- just a standard for it,
that the original red phosphors didn't meet.
I /remember/ this from 45 years ago. (I read "Radio-Electronics" and
"Electronics World".) The available red phosphor was not very efficient, and
when driven hard, it turned "orangey" at high current levels.
As for any differences between professional and consumer CRTs... It's true
that consumer CRTs were often designed for brightness * (rather than color
accuracy or gamut). About 15 years ago, Mitsubishi brought out a consumer
CRT with "filtered" phosphors that more-closely approached the NTSC standard
** -- at the expense of brightness. The sets using it quickly flopped,
because (at least then) people were more interested in brightness than
clarity.
* The default setting for most LCD and plasma sets is the "burn the viewer's
eyes" mode.
** The closer a primary is toward the edges of the chromaticity diagram, the
more saturated it is (ie, the less its output is diluted with white) -- and
it's therefore less bright.
B
Bob Larter
Guest
Dave Plowman (News) wrote:
--
W
. | ,. w , "Some people are alive only because
\|/ \|/ it is illegal to kill them." Perna condita delenda est
---^----^---------------------------------------------------------------
Ayup.
--
W
. | ,. w , "Some people are alive only because
\|/ \|/ it is illegal to kill them." Perna condita delenda est
---^----^---------------------------------------------------------------
B
Bob Larter
Guest
Leonard Caillouet wrote:
stick my Colorvision Spyder to it & measure it. That way, I know for sure.
--
W
. | ,. w , "Some people are alive only because
\|/ \|/ it is illegal to kill them." Perna condita delenda est
---^----^---------------------------------------------------------------
Me, if I want to know that my screen is rendering colour correctly, I
stick my Colorvision Spyder to it & measure it. That way, I know for sure.
--
W
. | ,. w , "Some people are alive only because
\|/ \|/ it is illegal to kill them." Perna condita delenda est
---^----^---------------------------------------------------------------