Setting Up Your Monitor's Gamma Level by Stuart Halliday
========================================================

Run the program !GammaSetup.
Click on its icon on the icon bar.
Display the example Gamma Drawfile by clicking on the 'eye icon' and you
will see a horizontal set of black to white rectangles.

Adjust the brightness of your monitor until the lefthand black rectangle
*just* shows a checker or chessboard pattern of alternate black and dark
grey squares instead of looking pure black.

Adjust the contrast control of the monitor until the white box at the
righthand edge of black to white rectangles looks pure white and not a grey.
(In a good quality monitor this will probably be somewhere in the middle
position of the contrast control).
        
Probably the screen display will now look brighter than what you would be
normally used to, this is normal.

Click on the 'Display Gamma' button and turn the 'Combined' option on.

Look closely from a normal viewing distance at the large white rectangle
with the darker white/grey box within it.

Adjust the Gamma level by clicking on any of the R,G,B arrows until the
inner grey box appears to be the same brightness as the white box
surrounding it.

The inner box may appear to almost disappear as the brightness of the two
boxes is equalised. But this does not have to be exact. If you can't get
them to match up exactly, don't worry or fuss over it. Just leave the
setting with the inner box appearing slightly on the dark side.

Now, turn off the Combined option and in turn do the same 'tuning' for the
individual Red, Green and Blue boxes.

The large white box will mismatch after you do this, but do not worry
about this.

That is it! Your monitor is now correctly 'tuned'.

If you at anytime alter the monitor settings or change mode you will
probably have to do this again.


As an example of Gamma correction. If you load the supplied JPEG image of
Sigourney Weaver into a JPEG viewer like ChangeFSI or similar you should
hopefully see a correctly Gamma corrected image and see the detail in her
leather jacket.


The RGB image.
==============
The RGB squares consists of a dithered pattern of pixels with
luminance values of 0 and 255, and the centre area contains pixels with only
luminance values of 128.
The eye averages out the dithered outer RGB box to 128 and you adjust the
Gamma level so that the inner box matches in brightness.
Thus you've performed a manual Gamma correction!

