Monitor Calibration: monitor gamma
You can use the following window to determine monitor gamma for your system. Move the slider until both sides match in brightness. For web use you'll want a gamma of 2.2, the sRGB standard. The sRGB color space also works well for inkjet printers. Older PC monitors have a gamma of approximately 2.4, while MACs have a gamma near 1.8. In a sense, the sRGB standard is a compromise between the two displays. It's a little too dark for PCs, and a little too bright for MACs. However, recent monitors adhere to the sRGB standard and have a gamma of 2.2.
You must use software to make gamma corrections. A change in gamma changes the shape of the brightness curve (see Theory). Most operating systems support a Color Management System (CMS) that allows you to control display gamma. An exception is NT4. If you're running NT4, you may want to upgrade to Windows XP for better color control. If you're using Adobe Photoshop you can make adjustments with Adobe Gamma.
On a Windows computer, click on Start > Settings > Control Panel, and double-click on the Adobe Gamma icon. De-select the View Single Gamma Only checkbox, and adjust each color individually. As you move each slider you'll see the display darken and lighten. You're altering the look-up table (LUT) that controls the monitor display. The RGB value of the smooth patch remains the same, but it is interpreted to a different brightness as you move the slider. If you left-click on the slider to give it focus, you can use the Arrow keys to adjust gamma. When done there should be no color tint in the following grayscale.
As a final pass in Adobe Gamma, select View Single Gamma Only and ensure that you have a gamma of 2.2.
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