Do the patches marked 0 and 10 in the grayscale appear to be the same? If they do then you need to calibrate your monitor black point. Do the patches marked 95 and 100 appear to be the same? If they do then you need to calibrate your monitor white point. If the patches have a color tint, you can correct problem by calibrating monitor gamma for each color channel individually.

Stand ten feet from your monitor and examine the above figure. If the smooth patch is darker or lighter than the background then you need to calibrate monitor gamma.