Monitor adjustments

For CRT monitors, increase the contrast of your monitor up to its maximum. For LCD screens, also increase the contrast, but you may need to stay well below the maximum. The correct setting can be judged by the almost (95%) black background, which should stay black and not become dark gray. Now adjust the brightness until there is a clear difference between the 100% and 90% black. However, the background should still be black and not become dark gray.

You should be able to see the difference between each "block".
If not, adjust your monitor for best viewing results.