Viewing Web pages by a Browser needs good Calibration of Brightnes and Contrast levels of the Computer Monitor. Most monitors I saw was not properly calibrated. You will see two calibration images in this page. A white one and a black one. These are negatives of each other.
Upper two rows:
After proper monitor adjustment you should be able to see all small rectangles in larger ones. There is one small rectangle per each large one. If you can't see some of them your monitor is not adjusted properly.
Lower two rows, and Gamma image:
These are for Gamma adjustment. The inner ractangles are %50 gray, and the outer raectangles consist of equall tones of dark and light colors to make a %50 color. In a gamma balanced monitor, you should see the outer and inner color mixtures in equal brightness. The grays should not be Green or any other color tinted tone of gray.
What these tiny lines are for? These vertical and horizontal lines are intended to measure horizontal and vertical resolution of your monitor. You should view neighbor light and dark lines as seperate colors. There are colored lines as well as B/W lines. Also the lines should appear strait not bowed.
Tune your monitor untill you can see all the recatngles in upper rows. Proper calibration means you miss no details in the dark and bright edges when viewing web graphics...