Extreme Gray-Scale with Color Bars Test (1024 x 768) September 16, 1998 This combination pattern lets you check the extremes of the gray scale, which are difficult to reproduce, and the standard primary and secondary colors. What to look for: The top dark gray scale is useful for examining the black level and reproduction near black. The bottom gray scale is useful for examining white saturation and reproduction near peak white. Each step should be visible, clearly distinct, graduated with intensity, and smoothly increasing from left to right. Look for a variation in color between steps, which indicates different black levels for the red, green, and blue primaries. ( For 16-bit color modes see below.) The color bars are used to check the overall appearance, quality, and saturation of the primary and secondary colors. This test is best performed in 24-bit modes (16.7 million colors), where the intensity scale is fine and increases in steps of 1. For 16-bit modes (65,536 colors), the intensity is coarse and increases in steps of 8, so many of the steps appear identical. Some of the brightest steps are invisible. Half the steps in both gray scales show a faint green tint. For 8-bit modes (256 color), the intensity increases in steps of 4. Some LCD and other flat-panel displays may be unable to reproduce accurately all the gray-scale steps, regardless of Windows color mode, because of inherent hardware limitations. Some steps may be missing, some may be identical to adjoining steps, and some may contain dithered pixels. What you can do: Use the top gray scale to adjust the monitor's brightness control. Turn the control all the way down so that most or all of the bars are invisible. Slowly increase the control until the steps marked 4 and 8 are just barely visible. Ambient light may affect the visibility of the darkest steps. Make sure the screen background area around the steps remains black. If any of the steps on the bottom gray scale are invisible, turning down the contrast control should improve their visibility. If things look all right, don't turn up the contrast; doing so could adversely affect image sharpness. Use the master test pattern instead. Note: for 16-bit color modes, the first clearly visible step should be 247. For 8-bit color modes, only step 253 should be invisible. See above. Washed-out colors are often caused by improper setting of the brightness and contrast controls. In order to obtain the maximum color saturation for your display, be sure to set the controls as above. Bright ambient lighting also washes out the screen and reduces color saturation and contrast. Turn down or redirect the lighting to the minimum needed for your work area. If there is a change in color of the steps with intensity, that can be adjusted if the monitor has RGB drive and background controls. If your graphics board has gamma correction or transfer function controls, those may be the source of the problem. Alternatively, you can use them to correct the problem.