various "middle" grays based on various criteria. The shades in the rightmost column will only be correct if viewed on a calibrated monitor; you can check if the 50% luminance level of your monitor is correct here. Note that LCD screens, even when correctly calibrated, often have a brightness that varies considerably depending on the viewing angle. When using the luminance level checker above, try stepping back and changing your position until the hatched rectangle in the center of the gray field appears to dissolve into the background. If the hatched rectangle does not appear to be of the same brightness, then the "middle grays" rendered in the table are not correctly displayed on your screen. Quarter luminance list (typical monitor calibrated to 2.2 gamma, 50% luminance gray has RGB hex 0xBA value, which is 0.5^(1/2.2)*255) * Context-dependent; an estimate is displayed here taking the environment where it appearsin the article into account and assuming a neutrally lit surround of 200 cd/m2. References Science of photography