Bit of a Con Really - Follow-up ...

The Natural Philosopher wrote:
Schrodinger's cat wrote:


"The Natural Philosopher" <tnp@invalid.invalid> wrote in message
news:gv6ovn$f8n$1@news.albasani.net...
meow2222@care2.com wrote:
The Natural Philosopher wrote:

You would think so really, but going back to film photography,
there are
reasons why portraits were always shot on e.g. Konica, landscapes on
Agfa or Fuji, , and no one used Kodak at all professionally -
Except for
Kodachrome..

NT

Film is a whole nother business. You've got a lot less control over
its 'colour settings' than you have with a display screen, and ditto
re optical linearity. The issues with an LCD screen are quite
different.

well in the sense that they all use combinations of RGB (or CYMK) to
produce a 'full colour spectrum'and none succeed perfectly for all
applications, they are considerably identical, actually.

No, they aren't.

Very basically, you have to understand that:

A printed image is sending reflected light to your eye. It can only
reflect some portion of the spectrum of light it has absorbed.

Color transparencies which are used in pro film applications say your
are a liar.
Click to expand...
Colour transparencies aren't printed images.

--
W
. | ,. w , "Some people are alive only because
\|/ \|/ it is illegal to kill them." Perna condita delenda est
---^----^---------------------------------------------------------------
 
The Natural Philosopher wrote:
Bob Larter wrote:
Andy Champ wrote:
The Natural Philosopher wrote:

Color transparencies which are used in pro film applications say
your are a liar.

Not really. Transparencies subtract some colours from the
transmitted light; prints subtract some from the reflected light.
Displays make their own...

And LCDs use a matrix of RGB filters over a backlight, which makes
them behave similarly to a transparency in a projector, with the
exception that you can tweak the RGB values to change the colour
balance - which you *can't* do with film transparencies.

Why do color enlargers come equipped with color filters then?
Click to expand...
You're completely missing the point. Once again, projected colour
transparencies are nothing like printed images.

--
W
. | ,. w , "Some people are alive only because
\|/ \|/ it is illegal to kill them." Perna condita delenda est
---^----^---------------------------------------------------------------
 
Dave Plowman (News) wrote:
In article <gvg82g$fuh$3@blackhelicopter.databasix.com>,
Bob Larter <bobbylarter@gmail.com> wrote:
You can't tweak the colour response of film,

You can during processing.
Click to expand...
Yeah, okay, you can, but it's rarely done.

--
W
. | ,. w , "Some people are alive only because
\|/ \|/ it is illegal to kill them." Perna condita delenda est
---^----^---------------------------------------------------------------
 
Geoffrey S. Mendelson wrote:
Bob Larter wrote:
You can't tweak the colour response of film, you can with CRTs or LCDs.

People have been known to do it with Ektachrome type film (Ektachrome,
Fijuchrome, AgfaChrome, Ilfochrome, etc) with varying success by tweaking
the exposure and development.
Click to expand...
That's true, but it's a joke compared to being able to directly tune the
black level & amptitude of RGB levels on an LCD panel or CRT.



--
W
. | ,. w , "Some people are alive only because
\|/ \|/ it is illegal to kill them." Perna condita delenda est
---^----^---------------------------------------------------------------
 
The Natural Philosopher wrote:
Bob Larter wrote:
The Natural Philosopher wrote:
meow2222@care2.com wrote:
The Natural Philosopher wrote:

You would think so really, but going back to film photography,
there are
reasons why portraits were always shot on e.g. Konica, landscapes on
Agfa or Fuji, , and no one used Kodak at all professionally -
Except for
Kodachrome..

NT

Film is a whole nother business. You've got a lot less control over
its 'colour settings' than you have with a display screen, and ditto
re optical linearity. The issues with an LCD screen are quite
different.

well in the sense that they all use combinations of RGB (or CYMK) to
produce a 'full colour spectrum'and none succeed perfectly for all
applications, they are considerably identical, actually.

You can't tweak the colour response of film, you can with CRTs or LCDs.

You can actually.
Click to expand...
Nothing like to the degree that you can with CRTs or LCDs.

--
W
. | ,. w , "Some people are alive only because
\|/ \|/ it is illegal to kill them." Perna condita delenda est
---^----^---------------------------------------------------------------
 
meow2222@care2.com wrote:
William Sommerwerck wrote:
meow2222@care2.com> wrote in message
news:1e56875d-3af4-4041-832c-c511a21147dc@n8g2000vbb.googlegroups.com...
William Sommerwerck wrote:

I guess it comes down to definitions and how 'full spectrum' is
perceived.
Rightly or wrongly, I tend to think of it as a spectrum which contains
the
same component colours in the same ratios, as natural daylight...
That's a reasonable definition for a video display, but it's not
sufficient
for source lighting. It's difficult to make a "full spectrum"
fluorescent
lamp, especially one that produces good color rendition for photograpy.

but I guess even that varies depending on filtering effects of cloud
cover and haze and so on. Even so, I'm sure that there must be some
definition of 'average spectrum daylight', and I would expect that any
display technology would aim to reproduce any colour in as closely
exact a way as it would appear if viewed directly under daylight.
The standard is D6500, a 6500K continuous spectrum from a black-body
source.
What you suggest is, indeed, the intent.

TBH I think this is overplaying the significant of daylight. Almost
any monitor is adjustable to suit preferences of anything from 5000K
to 10,000K, and some go lower. None manke any attempt to copy the
colour spectrum of daylight, they merely include the same colour temp
as daylight as one of the options. None of the major display types
have any ability to copy a daylight spectrum, as they're only RGB
displays.
I think you've missed the difference between recreating the original color
(or the illusion of same), and producing a photographically useful
illuminant. These are different.

You havent defined what you mean by a 'photographically useful
illuminant'
Click to expand...
One of 5500-6500K, typically.

--
W
. | ,. w , "Some people are alive only because
\|/ \|/ it is illegal to kill them." Perna condita delenda est
---^----^---------------------------------------------------------------
 
Arfa Daily wrote:
meow2222@care2.com> wrote in message
news:1e56875d-3af4-4041-832c-c511a21147dc@n8g2000vbb.googlegroups.com...
William Sommerwerck wrote:
I guess it comes down to definitions and how 'full spectrum' is
perceived.
Rightly or wrongly, I tend to think of it as a spectrum which contains
the
same component colours in the same ratios, as natural daylight...
That's a reasonable definition for a video display, but it's not
sufficient
for source lighting. It's difficult to make a "full spectrum" fluorescent
lamp, especially one that produces good color rendition for photograpy.


but I guess even that varies depending on filtering effects of cloud
cover and haze and so on. Even so, I'm sure that there must be some
definition of 'average spectrum daylight', and I would expect that any
display technology would aim to reproduce any colour in as closely
exact a way as it would appear if viewed directly under daylight.
The standard is D6500, a 6500K continuous spectrum from a black-body
source.
What you suggest is, indeed, the intent.

TBH I think this is overplaying the significant of daylight. Almost
any monitor is adjustable to suit preferences of anything from 5000K
to 10,000K, and some go lower. None manke any attempt to copy the
colour spectrum of daylight, they merely include the same colour temp
as daylight as one of the options. None of the major display types
have any ability to copy a daylight spectrum, as they're only RGB
displays.


NT

But take account of the fact that we're talking domestic television sets
here, not computer monitors. For the most part, TV sets do not display the
same type of content as a computer monitor, and do not include user
accessible colour temperature presets or adjustments, which is why I made
the point earlier that in general, LCD TVs are set correctly 'out of the
box'.

As far as overplaying the significance of daylight goes, I'm not sure that I
follow what you mean by that. If I look at my garden, and anything or
anybody in it, the illumination source will be daylight, and the colours
perceived will be directly influenced by that. If I then reproduce that
image on any kind of artificial display, and use a different reference for
the white, then no other colour will be correct either, which was ever the
case when CRTs were set up to give whites which were either too warm or too
cold, even by a fraction. Maybe we're talking at cross purposes here, or I'm
not understanding something properly, but it seems to me that the colour
temperature and CRI of the backlighting on an LCD TV, would be crucially
important to correct reproduction of colours.
Click to expand...
That's exactly correct. The colour temperature of the reference white
(ie; the WB) is vitally important for correct colour rendition. The eye
will adjust to an incorrect WB, but it will still be incorrect.

All I know is, is that the flesh tones were poor on the example that I saw,
compared to other LCD TVs which were showing the same picture. The
fundamental difference between those sets and the Sammy, was the CCFL vs LED
backlighting, so it seems reasonable to draw from that, the inference that
the backlighting scheme may well be the cause, no ?
Click to expand...
It's just as likely that, as you said, a salesbunny wound up the colour
control to make the image "look better". Go knows that it's common
practice in showrooms.


--
W
. | ,. w , "Some people are alive only because
\|/ \|/ it is illegal to kill them." Perna condita delenda est
---^----^---------------------------------------------------------------
 
William Sommerwerck wrote:
The ability of most consumers to do more than make a mess is
very unlikely. Even someone like myself, having calibrated displays
for 30 years, can't do much to align a color management system
without a GOOD meter. I can get gray scale improved, but not really
accurate.

Does anyone make cheap-but-good instrumentation? I could justify a $500
investment.

(I can hear you laughing now.)
Click to expand...
Not at all:
<http://spyder.datacolor.com/product-mc-s2e.php>

--
W
. | ,. w , "Some people are alive only because
\|/ \|/ it is illegal to kill them." Perna condita delenda est
---^----^---------------------------------------------------------------
 
"Bob Larter" <bobbylarter@gmail.com> wrote in message
news:gvgtf1$mc7$2@blackhelicopter.databasix.com...
William Sommerwerck wrote:

The ability of most consumers to do more than make a mess is
very unlikely. Even someone like myself, having calibrated displays
for 30 years, can't do much to align a color management system
without a GOOD meter. I can get gray scale improved, but not really
accurate.

Does anyone make cheap-but-good instrumentation? I could justify
a $500 investment. (I can hear you laughing now.)

Not at all: <http://spyder.datacolor.com/product-mc-s2e.php
Click to expand...

And the Spyder will let me set up my Pioneer Kuro correctly? Because that's
what we were discussing.

I already have a huey, which did a decent job on my computer monitor.
 
"William Sommerwerck" <grizzledgeezer@comcast.net> wrote in message
news:gvgiqq$kcb$1@news.eternal-september.org...
This is simply not true. Every display has a color gamut that is
limited by the maximum saturation of its primaries. You can
produce any color within that gamut but not any outside.

Correct.


Even if every flesh tone is in that gamut, that does not mean that
you will get the right flesh tones for a given combination of RGB.
In order to do so, you must have the same spectrum in the
primaries that you have in the camera filters...

This bothers me. It might be true in a practical sense, but it's always
struck me as being theoretically wrong (mostly because of the extreme
overlap of the eye's blue and green receptors). I won't start an argument,
though, because, even if my intuition is correct, I don't have the
"science"
to back it up.
Click to expand...

The overlap is caused by the shape of the standard observer curves and is
part of the very reason that using a narrow band RGB device may not produce
color properly. The CIE standard observer curves are precisely attempts at
modeling the response of the human visual system. For decades, cameras have
been calibrated to match them, and phosphors designed to do the same, to the
degree possible. Now, with narrow spectrum devices, we have to consider the
implications of those assumptions. It may be that in the future, we should
simplify the system and use a narrow band response in cameras and reproduce
the RGB in the same manner at the display. Then we can more easily predict
the output of RGB systems using a standard matrix.

Leonard
 
"William Sommerwerck" <grizzledgeezer@comcast.net> wrote in message
news:gvgvl8$ouq$1@news.eternal-september.org...
"Bob Larter" <bobbylarter@gmail.com> wrote in message
news:gvgtf1$mc7$2@blackhelicopter.databasix.com...
William Sommerwerck wrote:

The ability of most consumers to do more than make a mess is
very unlikely. Even someone like myself, having calibrated displays
for 30 years, can't do much to align a color management system
without a GOOD meter. I can get gray scale improved, but not really
accurate.

Does anyone make cheap-but-good instrumentation? I could justify
a $500 investment. (I can hear you laughing now.)

Not at all: <http://spyder.datacolor.com/product-mc-s2e.php


And the Spyder will let me set up my Pioneer Kuro correctly? Because
that's
what we were discussing.

I already have a huey, which did a decent job on my computer monitor.
Click to expand...
My experience with the spyder products and other tristimulus colorimeters
such as those from xrite and sencore (really just a version of the xrite
products) is that they are a poor choice for anything other than gray scale.
If you want to adjust a CMS properly, you need a spectrophotometer. The
minimum useful would be the i1 pro.

Leonard
 
The Natural Philosopher wrote:
Andy Champ wrote:
The Natural Philosopher wrote:

Color transparencies which are used in pro film applications say your
are a liar.

Not really. Transparencies subtract some colours from the transmitted
light; prints subtract some from the reflected light. Displays make
their own...


Ah, so that is why they are backlit then?

So they can 'make their own?
What a prat. An LCD display IS a color transparency.
Click to expand...
Thinking about this offline leads me to realise that there is a
fundamental difference between the operation of a slide and the
operation of an LCD display.

A slide consists of a series of coloured dots (CMY) mixed together in
such a way that they filter out some of the colour, and leave the rest.
A red dot will be produced where the G and B have been filtered out,
and only the R left.

An LCD consists of ADJACENT (not overlaid) coloured filters. So a red
dot is produced by having the B and G pixels opaque, and only the R one
(which always has no G or B) letting light through.

Andy
 
William Sommerwerck wrote:
"Bob Larter" <bobbylarter@gmail.com> wrote in message
news:gvgtf1$mc7$2@blackhelicopter.databasix.com...
William Sommerwerck wrote:

The ability of most consumers to do more than make a mess is
very unlikely. Even someone like myself, having calibrated displays
for 30 years, can't do much to align a color management system
without a GOOD meter. I can get gray scale improved, but not really
accurate.

Does anyone make cheap-but-good instrumentation? I could justify
a $500 investment. (I can hear you laughing now.)

Not at all: <http://spyder.datacolor.com/product-mc-s2e.php


And the Spyder will let me set up my Pioneer Kuro correctly? Because that's
what we were discussing.

I already have a huey, which did a decent job on my computer monitor.
Click to expand...
In that case, you might be able to rig up some way of using it on your
Pioneer.

--
W
. | ,. w , "Some people are alive only because
\|/ \|/ it is illegal to kill them." Perna condita delenda est
---^----^---------------------------------------------------------------
 
meow2222@care2.com wrote:
Leonard Caillouet wrote:
meow2222@care2.com> wrote in message
news:5d37b31f-e42c-4ba4-9bfc-6e8a4e03ee11@m17g2000vbi.googlegroups.com...
Arfa Daily wrote:
meow2222@care2.com> wrote in message
news:1e56875d-3af4-4041-832c-c511a21147dc@n8g2000vbb.googlegroups.com...
William Sommerwerck wrote:
I guess it comes down to definitions and how 'full spectrum' is
perceived.
Rightly or wrongly, I tend to think of it as a spectrum which
contains
the
same component colours in the same ratios, as natural daylight...
That's a reasonable definition for a video display, but it's not
sufficient
for source lighting. It's difficult to make a "full spectrum"
fluorescent
lamp, especially one that produces good color rendition for
photograpy.


but I guess even that varies depending on filtering effects of cloud
cover and haze and so on. Even so, I'm sure that there must be some
definition of 'average spectrum daylight', and I would expect that
any
display technology would aim to reproduce any colour in as closely
exact a way as it would appear if viewed directly under daylight.
The standard is D6500, a 6500K continuous spectrum from a black-body
source.
What you suggest is, indeed, the intent.

TBH I think this is overplaying the significant of daylight. Almost
any monitor is adjustable to suit preferences of anything from 5000K
to 10,000K, and some go lower. None manke any attempt to copy the
colour spectrum of daylight, they merely include the same colour temp
as daylight as one of the options. None of the major display types
have any ability to copy a daylight spectrum, as they're only RGB
displays.


NT
But take account of the fact that we're talking domestic television sets
here, not computer monitors. For the most part, TV sets do not display
the
same type of content as a computer monitor, and do not include user
accessible colour temperature presets or adjustments,
fwiw my main set does, and I'm sure its not unique. Generally though a
TV is a much lower quality animal than a monitor, and displays much
lower quality data.


which is why I made
the point earlier that in general, LCD TVs are set correctly 'out of the
box'.
because they can be. CRTs are more variable, and the circuits used to
drive them a lot less precise, partly because CRT sets are generally
older, and the sort of standards expected in monitors have only begun
crossing over to tvs in recent years.


As far as overplaying the significance of daylight goes, I'm not sure
that I
follow what you mean by that. If I look at my garden, and anything or
anybody in it, the illumination source will be daylight, and the colours
perceived will be directly influenced by that. If I then reproduce that
image on any kind of artificial display, and use a different reference
for
the white, then no other colour will be correct either,
what makes you think that just one specific colour temp is 'correct'?
Real daylight is all over the place colour temp wise, and the end user
experiences those changes without any problem. Also any self
respecting monitor offers a range of colour temps, since its nothing
but a taste matter


which was ever the
case when CRTs were set up to give whites which were either too warm or
too
cold, even by a fraction.
but thats down to historic reasons, customers never expected precise
colour temp, and screens were routinely set up by eye. The circuits
involved couldnt set themselves up the way a modern LCD set can, there
was normally no feedback on colour channels, just open loop CRT gun
drive on top of a massive dc offset, so the systems were inherently
variable. Plus the fact that CRT gamma was often way off from the real
world made it hard, or should I say impossible, to set such sets to
give a faithful reproduction in other respects anyway.


Maybe we're talking at cross purposes here, or I'm
not understanding something properly, but it seems to me that the colour
temperature and CRI of the backlighting on an LCD TV, would be crucially
important to correct reproduction of colours.
It has almost nothing to do with it, because the level of each colour
channel output on the screen depends on both the light source and the
settings of the LCD R,G,B channels. Within reason, any temperature
colour backlight can produce any temperature colour picture.


All I know is, is that the flesh tones were poor on the example that I
saw,
compared to other LCD TVs which were showing the same picture. The
fundamental difference between those sets and the Sammy, was the CCFL vs
LED
backlighting, so it seems reasonable to draw from that, the inference
that
the backlighting scheme may well be the cause, no ?

Arfa
Its just a guess. In fact any desired flesh tone can be reproduced
using almost any colour temp backlight, certainly anything from 3,000K
to 10,000K. Think about the process, you've got 3 colour channels,
each of which has a given level of light from the backlight, which is
then attenuated to any desired degree by the LCD pixel.


NT

While this is true, it would be virtually impossible to get all colors right
with some arbitrary color backlight. You could get a subset right and get
all the others completely wrong.

Leonard

With each colour channel you've got everything available from
backlight output x LCD max down to backlight output x LCD minimum.
AFAIK that covers every flesh tone on this planet, unless one goes
down to 2000K backlight or some other very extreme value.
Click to expand...
The problem with LCD monitors is they typically only have 6 bits (64
levels) of resolution for each colour channel, so you don't have a lot
of scope for tweaking the WB via the LUTs. Do it that way, & you'll lose
tonal detail, resulting in posterisation.

--
W
. | ,. w , "Some people are alive only because
\|/ \|/ it is illegal to kill them." Perna condita delenda est
---^----^---------------------------------------------------------------
 
And the Spyder will let me set up my Pioneer Kuro correctly?
Because that's what we were discussing.
I already have a huey, which did a decent job on my computer monitor.

In that case, you might be able to rig up some way of using it on your
Pioneer.
Click to expand...
Uh-huh.
 
meow2222@care2.com wrote:
William Sommerwerck wrote:
I was about to jump on that, but it's basically correct. However,
you'd want the backlight to be "reasonably close", so you didn't
have to push any channel to its limits of adjustment.
... not really. The backlight on this monitor is far removed from the
colour temp its operating at, and all is well. When its far removed it
does affect contrast ratio a bit.
I have to disagree. Suppose the backlight doesn't produce sufficient blue
for the desired color temperature. You can compensate by displaying the blue
pixels at a higher luminance level. But you can't go higher than 100% -- the
lightest (highest) level the LCD can transmit. That level might not be
enough to match the green and red levels.

indeed, but you'd have to have a huge mismatch between backlight CCT
and displayed image CCT for that problem to occur. A 15,000K backlight
with a 5000K display works just fine.
Click to expand...
There's no such thing as a 5000K LCD display, sans backlight. Until you
put light through it, an LCD doesn't have a colour temperature at all.

A roughly similar situation occurs with color-negative film. If you expose
daylight-balanced film at 2800K, the blue layer might be unacceptably
underexposed, and no amount of additional blue-layer exposure during
printing will restore the lost shadow detail. Ditto for exposing 3200K film
under daylight, except the error is on the side of overexposure.

yes that happens with film, but nothing like it happens with an LCD
display. What happens is that if your image is far removed from the
backlight in terms of CCT, then one of the RGB LCD colour channels
operates over part of its potential range, not the full range. So for
example on this display the B pixels might never exceed 50% light
transmission. It doesnt cause a problem.
Click to expand...
Yes, it does. It drastically reduces the number of transmission levels
available to the pixels of that colour, causing posterisation & colour
distortion. The more out of whack the colour temperature of the
backlight is in comparison to the desired colour temperature of the
image, the worse the problem will get.
Unlike CRTs, the transmission value of an LCD pixel isn't infinitely
variable, they only work in steps.


--
W
. | ,. w , "Some people are alive only because
\|/ \|/ it is illegal to kill them." Perna condita delenda est
---^----^---------------------------------------------------------------
 
Dave Plowman (News) wrote:
In article <Z_8Sl.165924$A85.12428@newsfe03.ams2>,
Arfa Daily <arfa.daily@ntlworld.com> wrote:
I think that I would have to contest your point of "very limited
control". All of the (recent) half-way decent LCD screens that I have
seen to date, have a perfectly adequate contrast ratio. Certainly, the
one in my kitchen produces deep enough blacks and bright enough whites
to be absolutely fine under the pretty intense flourescent light that I
have in there. This is one of the reasons that I question the
requirement to extinguish areas of the backlighting in order to
'improve' the rendition of blacks.

If you're just watching casually under high ambient lighting, the quality
of the blacks is pretty irrelevant. It's when you're doing some serious
viewing under subdued lighting that it matters. And this is exactly where
ordinary backlit LCD falls over against CRT.
Click to expand...
Exactly. It's why CRTs are better than LCDs for editing photos, for example.

--
W
. | ,. w , "Some people are alive only because
\|/ \|/ it is illegal to kill them." Perna condita delenda est
---^----^---------------------------------------------------------------
 
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