How to adjust colours?

[Terry Pinnell]

I have a HP p930 19" CRT monitor. I'm using the 'NVIDIA Display
Optimization Wizard' on my XP Home PC with the aim of improving the
display appearance. Mid way through, I'm totally baffled by this
section about Color Temperature. This are the instructions.

"Setting the color temperature, or chromanicity, on all your displays
to the same value will give you the same shade of white. 6500K is a
widely used setting to accurately represent white.

Using the controls on your displays, set the color temperature to the
value that most accurately represents white to you. It is recommended
that you apply the same setting to all displays.

When you have set all your displays to the same value, click Next."

This seems to be making the assumption that I'm using multiple
'displays' (Monitors), yes? But nowhere mentions the presumably much
more common single monitor scenario, which is the case here.

OK, I then found the PDF manual, and see this:
http://img186.imageshack.us/img186/1144/hpp930coloursyj6.jpg

But that's as clear as mud to me. What are these three 'Colors1',
'Colors2' and 'Colors3' meant to be? I've used the monitor menu
buttons to get to that section, and my current settings are:
Colors1 9300 (extreme left)
Colors2 6500 (midway)
Colors3 5000.

In all 3 cases, R, G and B are set to 50.

Could someone step me through the procedure from this point please?
I'm sure it will be embarrassingly obvious, but right now I'm lost!

 

[Bob Myers]

OK, I then found the PDF manual, and see this:
http://img186.imageshack.us/img186/1144/hpp930coloursyj6.jpg

But that's as clear as mud to me. What are these three 'Colors1',
'Colors2' and 'Colors3' meant to be? I've used the monitor menu
buttons to get to that section, and my current settings are:
Colors1 9300 (extreme left)
Colors2 6500 (midway)
Colors3 5000.

"Color 1," "Color 2," and "Color 3" are three adjustable
settings for white point; as shipped, it appears that "Color 2"
was intended to provide the 6500K white. The manual page
you provided gives the instructions for changing the white
point assigned to any of these presets; you may either adjust
a slider which will supposedly give you a direct readout of
the "color temperature" directly, or you can adjust the
relative amounts of red, green, and blue directly to obtain
the desired white. It will not be possible to set the white
accurately using the "RGB" controls unless you have either
an existing reference and a good eye, or use a colorimeter
(color calibration tool) to assist you in these adjustments.
In either case, what's actually going on is that you are varying
the relative amounts of red, green, and blue which combine
to make white - it's just that when you use the "color temperature"
form of the setting, the software is calculating the required
R, G, and B settings for you. A good place to start, IF you
have some means of measuring the luminance of the three
colors individually, is typically about 60% green, 30% red,
and 10% blue (again, in terms of the actual luminance of each
color - which is not necessarily the number you will see via
the on-screen display.) Without any sort of measurement
device, the best you can do is simply adjust the "temperature":
setting or the individual RGB controls until the white (and other
colors in an image) looks "right" to you.

Setting the white point is one aspect of getting the color to be
accurate in a display, and on a CRT monitor it's usually the
only one you can readily adjust. A white point which
corresponds to a color temperature of about 6500K is
the most common standard for most applications; 9300K
is a distinctly bluish white, and was used for computer monitors
only because it permitted higher brightness specs (since it
brought in considerably more blue than the 6500K setting).
5000K or 5500K is sometimes used as a "paper" white, if
you're doing a lot of document work, and it somewhat
redder than the 6500K setting.

Bob M.