Accurate Image Manipulation for Desktop Publishing
Calibration

Setting the Brightness and Contrast of the CRT monitor Accurately

This method gives the most accurate Brightness and Contrast setting for CRT monitors. It results the same accurate black-point no matter if a system level gamma calibration is active or not since only the R,G,B=0,0,0 level (pure black) is used and the pure black is not affected by any CRT gamma correction. This method is also platform independent.

1.
Set the room lighting to normal image editing condition. This is dim or moderate, not light. Minimize possible glare (so that the CRT screen is not directly exposed to light sources).
 
2.
Let the monitor to warm up for 1 hour in order to allow it stabilize.
 
3.

This method needs a level 0 background on the desktop. Go to the Display Properties, select Appearance-tab, then choose Item=Desktop and change it's color to Black, verify that it is R,G,B=0,0,0.

In case you have plenty of icons on the desktop drag them to the bottom of the screen so that their luminance affects as little as possible to your vision.

 
4.

Locate the the Contrast control of your monitor. This control adjusts the maximum displayed luminance, so it is range control. It is best to keep it always at maximum, only if the highlights are too light for your vision bring it down to a suitable level.

Set the Contrast control of the monitor now to the maximum.


This is often called as the Contrast. Actually it adjusts the maximum luminance level of the monitor.

 
5.

Locate the Brightness control of your monitor. Despite of it's name this control affects to the black-point of your system. If the it is at a too low setting then the monitor does not show dark shades of the images properly they are cut off to pure black. If it is at a too high setting then very important part of the available contrast range is not used, there is no good black anywhere on the screen and all the images appear flat and foggy.

Set the Brightness control of the monitor now to maximum as the starting point of the black-point calibration.


This is often called as the Brightness. Actually it adjusts the the black-point of the monitor.
 
6.

Locate the Vertical Height control of your monitor to make the active scanned display area vertically smaller, so that a black border will appear on top and at the bottom of the screen. This black area is now not scanned by the electron beam at all so it gives a perfect black reference point, as good black that there can be on the CRT.


Vertical Height or
Vertical Size
control

 
7.

You should now have a situation like this on your desktop. If it is so then jump to step 8.

else continue with step 7a.

 
7a.

In case it is not possible to adjust the CRT so that the non-scanned area is visible in step 7 then undo step 6 and locate the Vertical Centering control of your monitor,


Vertical Centering or
Vertical Position
control.

 
7b.

and use the Vertical Centering control to move the active scanned display area downwards until you can see the non-scanned area at the top of the monitor screen. If it is so then jump to step 8.

else continue with step 7c.

 
7c.

Some monitors do not show the non-scanner area at all. With such monitors show full screen black with absolutely nothing else shown but the R,G,B level 0,0,0 all over the screen. Do not use the DOS-prompt to show a black screen since the DOS prompt often switches to a different refresh mode. Now make the room completely black, with no light at all. Set the brightness to minimum and slowly increase it until the screen starts to emit light. Now adjust slowly and carefully back and forth around this point until you find the exact location that is just below the point where the screen emits light.

Jump to step 9.

 
8.

Now use the Brightness control to adjust the active area so that it just merges with the black of the non-scanned area.

The Brightness setting has to be on the verge so that the smallest increase to it would make the active scanned area discernible.

 
9.

Blackpoint calibration is now complete. Please adjust the scanned area back to how it was.

Remember to keep the the ambient lighting level low or moderate and especially constant and do remember to calibrate the blackpoint periodically, but only after the monitor has been stabilized.

If you have system (gamma) calibration such as AdobeGamma active you will need to re-check it now but do not adjust the black-point there, it is now very accurately set.

 
Where to go

Gamma-space evaluation is here

Photoshop calibration page is here

An easy but very accurate method to calibrate the color-temperature of the monitor to daylight (D6500) is explained on the Photoshop calibration page but is not Photoshop spesific.


Accurate Image Manipulation for Desktop Publishing   

Copyright Timo Autiokari, 1999-2003. Contact info