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Monitor calibration - can I approximate it this way?

 
 
Peabody
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      04-17-2008
My old CRT died, and I've picked up a used Dell 21" Trinitron, vintage
1998. I'm having some trouble getting it to look good. In
particular, it seems too warm at the factory default settings, both at
6500k and 9300k.

This monitor has individual RGB adjustments for both bias and gain,
and I wondered if I can use something like these pictures:

http://brighamrad.harvard.edu/resear.../tutorial.html

to adjust it more or less properly to display a neutral gray. In
playing with it, I find that I can either adjust the reds lower, or
the greens higher, to get true gray, and the latter seems to provide
the most pleasing outcome, particularly when I have contrast turned
down as I often do for text work.

Is there a proper way to adjust the bias and gain settings? In other
words, it looks like I could achieve a true gray with all six settings
set at relatively low levels, or at relatively high levels. Does it
matter which I choose?


 
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Kevin McMurtrie
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      04-18-2008
In article <T0NNj.106107$(E-Mail Removed)>,
Peabody <(E-Mail Removed)> wrote:

> My old CRT died, and I've picked up a used Dell 21" Trinitron, vintage
> 1998. I'm having some trouble getting it to look good. In
> particular, it seems too warm at the factory default settings, both at
> 6500k and 9300k.
>
> This monitor has individual RGB adjustments for both bias and gain,
> and I wondered if I can use something like these pictures:
>
> http://brighamrad.harvard.edu/resear.../tutorial.html
>
> to adjust it more or less properly to display a neutral gray. In
> playing with it, I find that I can either adjust the reds lower, or
> the greens higher, to get true gray, and the latter seems to provide
> the most pleasing outcome, particularly when I have contrast turned
> down as I often do for text work.
>
> Is there a proper way to adjust the bias and gain settings? In other
> words, it looks like I could achieve a true gray with all six settings
> set at relatively low levels, or at relatively high levels. Does it
> matter which I choose?


There are three settings per channel - black point, midpoint, and white
point. All are critical for getting the color temperature exactly
right. Usually these are easily accessible on the analog board on the
back of the tube or on the side of the main board. Parts on the analog
board float around 900V so use a plastic screwdriver. Analog
adjustments on the main board are usually referenced to ground. The
flyback transformer shield may have line AC.

Tubes also have that cluster**** of beam alignment magnets on them for
color purity and geometry. If you're lucky, the only adjustment is
gluing geometry magnets back on when they fall off. Don't even think
about touching the rotating magnets unless you have the service manual
to tell you the adjustment procedure.

And most importantly if you open up the case, watch out for
electrostatic discharges coming off the red anode wire. The reflex
muscle jerk can cut your hand on a sharp object or, worst of all, cause
you to accidentally break the tube.


I'm glad CRTs are obsolete!

--
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Reply with Google and I won't hear from you.
 
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Paul Furman
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      04-19-2008
Peabody wrote:
> My old CRT died, and I've picked up a used Dell 21" Trinitron, vintage
> 1998.


I have a Sony Trinitron Multiscan G500 of about the same age. It has
developed a case of epilepsy and looks awfully low contrast compared to
my new laptop screen which runs as a dual monitor side by side with it.

> I'm having some trouble getting it to look good. In
> particular, it seems too warm at the factory default settings, both at
> 6500k and 9300k.
>
> This monitor has individual RGB adjustments for both bias and gain,


I follow the procedure with Photoshop's 'Adobe Gamma' thingy in the
control panel which as I recall starts with maxing out contrast and
adjusting brightness on the monitor's menu button then I thought the
rest was done through the applet thingy including white balance and
gamma (midpoint brightness).

> and I wondered if I can use something like these pictures:
>
> http://brighamrad.harvard.edu/resear.../tutorial.html
>
> to adjust it more or less properly to display a neutral gray. In
> playing with it, I find that I can either adjust the reds lower, or
> the greens higher, to get true gray, and the latter seems to provide
> the most pleasing outcome, particularly when I have contrast turned
> down as I often do for text work.
>
> Is there a proper way to adjust the bias and gain settings? In other
> words, it looks like I could achieve a true gray with all six settings
> set at relatively low levels, or at relatively high levels. Does it
> matter which I choose?
>
>

 
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