Allow the Monitor to Stabilize

Set up the normal room lighting that you will be working with. Make it rather dim and eliminate glare as much as is possible (set the lighting so that the monitor screen is not directly exposed to the lighting).
 
Let the monitor to stabilize for at least 1 hour, this is very important !

Verify that your display driver card is set to 24-bit color (or true-color or 32-bit) mode. 

Set the Color-Temperature

The scale of the color temperature control of CRT monitors as well as the built-in presets are most often not accurate at all. To accurately set the monitor to daylight color temperature (6500K or D65) do the following:
   
At noon 11:00 am... 2:00pm, (not in the morning and not in the evening but at noon) on a sunny day, position the monitor in front of a window so that you can see both the monitor and the outside real-world. Turn off all interior lighting.
 
 In adobe Gamma utility:

• verify that Color Temperature/Hardware is set to D6500.
• verify that Color Temperature/Adjusted is set to "Same as Hardware".

Now on the monitor show a large (about 4x4 inch or 10x10cm) pure white (RGB=255,255,255) square area in the center of the screen on pure black background.

It is absolutely mandatory that there is nothing else on the screen but the pure white square RGB=255,255,255 in the center and the remaining screen area at pure black RGB=0,0,0.

Now do the following:

1. view the outside real-world daylight scene for a minute or two in order to adapt your vision to the true daylight and only after that:
2. take a quick look, no longer than 3 seconds, at the monitor white. If it appears to have a color-cast adjust the color temperature control(s) of your monitor. These is only a couple of second until the vision starts to adapt to the monitor white so be quick.
3. Repeat 1 and 2 until the monitor white does not appear to have a cast.

Choose the system gamma space

Choose the desired system gamma space. This decision mainly affects to how the uncalibrated world (like the Web, non color-managed software etc.) appears on your ICC color-managed system. It also affects to how the Widows color-scheme appears, this can be adjusted in DisplayProperties.

How to choose the system gamma space:

• Gamma space 1.72 is the gamma space of uncalibrated Mac systems.
• Gamma space 2.50 is the gamma space of uncalibrated PC systems.
• Using gamma space 1.00 as the system space has the benefit of avoiding the slope-limiting issue in the on-the-fly display conversion in Photoshop but the drawback is that the range of the CRT is not being utilized the best possible way (and the Web appears very incorrectly in the browsers).

  With well behaving ICC color-managed workflow such as the Photoshop 6.0.x combined with AdobeGamma provides (less the slope-limiting issues) there are no technical or any other reasons to calibrate the monitor to any other space than to close to the native characteristic of the CRT monitor that is gamma 2.5. This gives the additional benefit that the system is then in same gamma space as the vast majority of the systems on the Web are.

  In case you calibrate to gamma 2.5 do use the new Color Dither Gamma Calibration Target.

Else choose the gamma calibration chart of your choice below and show it in your browser or better, have your browser to set the gamma chart as the background image of your desktop by right-clicking the displayed image and then selecting the "Set as Background" from the pop-up menu.

1.0 / 1.1 / 1.2 / 1.25 / 1.3 / 1.4 / 1.5 / 1.6 / 1.72 / 1.8 / 1.9 / 2.0 / 2.1 / 2.2 / 2.3 / 2.4

Larger monitor calibration charts:

• Gamma 1.0 chart
• Gamma 1.25 chart
• Gamma 1.6 chart

Make a note of the name of the profile, cancel the Adobe Gamma, then using the Windows Explorer go to c:/windows/system/color and remove (cut and paste elsewhere) that profile.  This will discard the ready made profile, ready made profiles are not accurate. 
 
Repeat the above until Adobe Gamma says "Adobe Monitor Settings" in the Profile box.
 
Press Next.

Here the Phosphors info are set. In case you know the Phosphor chromaticity values of your monitor enter them by selecting "custom" from the Phosphors dropdown list box. If you do not have these values then select Phosphors: Trinitron. CRT monitors either have Phosphor-set that has the name "Trinitron" or another set that has the name "P22" (or "EBU"). They are very close to each other, Trinitron will match the monitor well in both cases.

To query the chromaticities from the monitor download the free DDCtest utility, kindly provided by EnTech Taiwan, it is 137kB only and needs no installation, just download it to a suitable directly and then run (double-click it) from there. Note that the gamma and whitepoint information in the monitors EDID are usually way incorrect, rgb x,y chromaticities are most often correct, they should give you more accuraty in Photoshop. If you do this please e-mail me the following information:

Model: (from the monitor, the rest below from DDCtest utility)
Mfgr:
ModelID:
gamma:
red x:
red y:
green x:
green y:
blue x:
blue y:
white x:
white y:

Thank you for you support!

Please note that the phosphor-set that has the name "Trinitron" has nothing to do with one of the shadow mask technology that also has the name "Trinitron".

Press Next. 

Now you are about to calibrate the gamma, have the downloaded monitor calibration chart visible.
 
Set the "desired gamma" value in Adobe Gamma utility to the gamma space you have chosen in step 3.
 
Check the view single gamma only check box (if it was not selected already). 
 
Now use the gray slider to get a as good gamma match as possible all over the chart, please remember that the gamma swatches must be viewed at such distance that the dithering is fully averaged by the eye, this is about 1 to 2 meters away (3 to 6 feet). To start with, make large changes to gray slider in order to familiarize how it affects to the gamma chart, then with small movements try to match the gray gamma as accurately as possible.

The monitor can possibly have imbalance between the gammas of the red, green and blue guns, the gamma chart will show this very easily. Next you will be correcting this gray balance. Un-check the "view single gamma only" check-box. 
 
To start with, make a large changes to the red slider in order to familiarize how it affects to the gamma chart. In addition to an overall gamma change you will notice hue change in both the continuous tone portion and dithered portions of the swatches in the gamma chart.
 
Now use the red slider to balance, as much as is possible, the reddish tint between the continuous tone portions and in the dithered portions of all the gray swatches. Your vision is by now adapted rather interestingly but it does not matter at all, just balance, as much as is possible, the reddish tint between the continuous tone portions and in the dithered portions of all the gray swatches. Do not try to make the chart "gray" using the red slider, instead try to balance the reddish tint between the continuous tone portions and in the dithered portions of all the gray swatches.
 
Now use the blue slider to balance as much as possible the bluish tint between the continuous tone portions and in the dithered portions of all the gray swatches. Again: your vision is by now adapted even more interestingly but it does not matter at all, just balance, as much as is possible, the bluish tint between the continuous tone portions and in the dithered portions of all the gray swatches. Do not try to make the chart "gray" using the blue slider, instead try to balance the bluish tint between the continuous tone portions and in the dithered portions of all the gray swatches.
 
Repeat both the red slider and blue slider adjustments until there is no color difference between the continuous tone portions and in the dithered portions of all the gray swatches.

And then, it is possible that the gamma match is not good anymore (or anyhow). If you determine that the chart now has green difference between the continuous tone portions and in the dithered portions or that the overall gamma is still incorrect then increase/decrease the green slider a little.  This will offset all the color balance so you need to repeat the red-slider, blue-slider then again red-slider and again blue-slider adjustment as described above. 
 
Adjust & evaluate until accurate. It is somewhat tedious but well worth of the effort. 
 
Press Next.