If you're using a flat (TFT LCD) screen, the very first thing to do is to position your monitor so you can view it comfortably. Sit as you would normally sit. This is important since the gamma varies with viewing angle. As you'll soon se, gamma also varies along the height of the screen due to slight differences in viewing angle.
The second thing to do is to adjust the contrast and brightness of your screen so that all 11 blocks of the greyscale gradients on this page are possible to distinguish. Obviously, the brightest should be bright white and the darkest should be black. Each step should be a 10% increase in luminance.
This page is made specifically with TFT LCD flat-screens in mind. If you use a CRT screen, all strips on this page will look identical. However, if you're using a flat screen you'll probably see that the difference between the two darkest squares is less at the top of the screen than at the bottom. That's an effect of the different parts of the screens being viewed from different angles.
(at gamma 2.2)
|Hex colour code||#00||#59||#7c||#95||#aa||#bc||#cb||#da||#e7||#f3||#ff|
The third thing to do is to adjust the gamma of the screen. Scroll the page a bit so that the striped box below ends up roughly in the middle of the screen or slightly above. If your screen gamma is 2.2, the striped box, should, if you squint really hard, blend in with the grey background without any visible difference in brightness.
If the square is darker than the background, your screen gamma is less than 2.2, and vice verca. If you're using a flat screen, try tilting the screen up or down (if possible). You should see how this affects the visibility of the box, or rather, the darkness of the background. If you can get it to blend in without the screen being at too weird of an angle – great, you're done! If you can't, or if you're using a CRT, you'll need some software. Thankfully, there is simple yet useful free software which works great. QuickGamma is my favorite so far. Use the
Help button for guidance on how to set your monitor gamma to 2.2. It can be a bit tricky to determine, so be patient! (I found it easier to just look at the square on this page rather than the graphics in QuickGamma itself.) After having set the gamma, check the
Run QuickGammaLoader at Windows Startup, you're done!