Setting color on monitor to display only grayscale?

  • Thread starter Thread starter Michael Linford
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Michael Linford

I have a two year old laptop with a video card problem. It doesn't display
reds, either on the LCD screen or an external monitor. I have tried cleaning
the contacts, still no luck. It is out of warranty and the price of parts is
pretty high, so I've decided to buy a new laptop. But I would like to keep
this one around as a backup since it still works fine other than the video
card. I think I could tolerate it if I disabled the greens and blues as well
and essentially turn it into a grayscale display. Would this even work, and
if so how would I do it?
 
Michael Linford said:
I have a two year old laptop with a video card problem. It doesn't
display reds, either on the LCD screen or an external monitor. I have
tried cleaning the contacts, still no luck. It is out of warranty and
the price of parts is pretty high, so I've decided to buy a new
laptop. But I would like to keep this one around as a backup
since it still works fine other than the video card.
Click to expand...

You'll find it works surprisingly well without doing anything special.
 
Michael said:
I have a two year old laptop with a video card problem. It doesn't display
reds, either on the LCD screen or an external monitor. I have tried cleaning
the contacts, still no luck. It is out of warranty and the price of parts is
pretty high, so I've decided to buy a new laptop. But I would like to keep
this one around as a backup since it still works fine other than the video
card. I think I could tolerate it if I disabled the greens and blues as well
and essentially turn it into a grayscale display. Would this even work, and
if so how would I do it?
Click to expand...

For a hardware failure, that is pretty strange. AFAIK, the connection to the
LCD panel, is digital via low voltage differential signalling. That doesn't use
the DAC in the GPU. The VGA monitor connection on the back, has RGB as
analog signals. A broken pin, disconnected wire, or a failure in the red
channel could account for one color going missing. Having equivalent failures
seems unlikely from a hardware perspective. And having a failure deep in the
logic somewhere, without breaking the chip, is pretty unlikely.

Are you sure this isn't a problem with a gamma setting or something ?
(Like a change that has only been applied to the red channel.)

http://common.packardbell.com/itemnr/instr_atiradeondrivers/ati_color.jpg (ATI)

or page 103 here, for Nvidia
ftp://download.nvidia.com/Windows/84.12/84.12_Forceware_Display_Property_User_Guide.pdf

Do you get the same response, if you boot with a read-only Linux
distro like Knoppix (knopper.net) ? There may be some version of Ubuntu that allows
the same thing. The CD doesn't install anything, and allows you to boot
up a Linux desktop. Try that, and see if the color space is normal there.

Paul
 
There are no gray pixels. The display has red, green, and blue pixels. If the red does not work and you turn off the green and blue you will have nothing.
 
I have a two year old laptop with a video card problem. It doesn't
display reds, either on the LCD screen or an external monitor. I
have tried cleaning the contacts, still no luck. It is out of
warranty and the price of parts is pretty high, so I've decided to
buy a new laptop. But I would like to keep this one around as a
backup since it still works fine other than the video card. I think
I could tolerate it if I disabled the greens and blues as well and
essentially turn it into a grayscale display. Would this even work,
and if so how would I do it?
Click to expand...

Without red there is just no way to achieve gray. Grayscale would be
achieved on an RGB system by setting the red, green and blue to equal
values in the pixels, so you could, for example achieve 256 levels of
gray by using RGB vlaues 0,0,0 though 255,255,255 with 24-bit color. If
the red is missing then you can't do that.

Are you 100% certain this isn't a software problem? Do the colors appear
wrong when the machine is booting (before the OS loads)? Have you tried
to boot a live linux CD or to go into the BIOS setup and see if the
colors appear wrong?
 
(e-mail address removed) wrote in
he is occasionally right, and he is on this one.
Click to expand...

Right about what? Buying a new laptop or keeping the old one around as a
backup?
 
If no red signal is getting to the LCD then you'll have "cyan scale" and not
grey scale. All reds will be missing.

Depending on what is broken, you MIGHT be able to accomplish what you want
by shorting the red wire to the blue or green wire.

Does the laptop have a VGA port? What happens when you connect a monitor?
 
Without red there is just no way to achieve gray. Grayscale would be
achieved on an RGB system by setting the red, green and blue to equal
values in the pixels, so you could, for example achieve 256 levels of
gray by using RGB vlaues 0,0,0 though 255,255,255 with 24-bit color. If
the red is missing then you can't do that.
Click to expand...

but the eye/brain compensates, and a crt with no red channel can look
ok if youre working at it, ie paying it most of your attention. Better
to leave it in colour than go to B&W, then you'll still have greens and
blues as well as sort-of-grey. But your red orange and yellows are all
history.


NT
 
Not doing anything special, stupid.


Continuing to have the old laptop around as a backup,
and just put up with the loss of red with that.
Click to expand...

Yeah, not doing anyrhing to the old laptop and buying a new one will
work. Who would hav ever guessed that?
 
(e-mail address removed) wrote in
Well he only made one claim that i quoted, so I'll let you figure it
out.
Click to expand...

Yeah I see it, but it doesn't say anything other than buying a new
laptop to replace the old one will work. A great piece of advice
indeed. Such insight is rare.

The bit about grayscale certainly won't work if red doesn't work.
 
Yeah, not doing anyrhing to the old laptop and buying a new one will work.
Click to expand...

HE said he wanted to keep the old laptop in reserve and
was asking about running the screen in grayscale, ****wit.

Running it in grayscale isnt possible, putting up with the loss of red is surprisingly viable.
Who would hav ever guessed that?
Click to expand...

Thanks for that completely superfluous proof of what a terminal ****wit you have always been.
 
Mitch Crane said:
(e-mail address removed) wrote
Click to expand...
Yeah I see it, but it doesn't say anything other than
buying a new laptop to replace the old one will work.
Click to expand...

Thats because that fool Pawl molested the quoting, ****wit.
A great piece of advice indeed. Such insight is rare.
Click to expand...

So stupid that it didnt even bother to check the original.
The bit about grayscale certainly won't work if red doesn't work.
Click to expand...

But ignoring the lack of red is surprisingly viable, ****wit.
 
but the eye/brain compensates, and a crt with no red channel can
look ok if youre working at it, ie paying it most of your attention.
Click to expand...

And some Win color schemes dont use red much at all. So all you really
notice is that the red X in the top right hand corner isnt red anymore etc.

Hardly the end of civilisation as we know it any time soon.
Better to leave it in colour than go to B&W, then you'll still have greens and
blues as well as sort-of-grey. But your red orange and yellows are all history.
Click to expand...

Yeah, its surprisingly usable.
 
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