The lack of standardization in calibrating monitors has caused significant problems with systems such as the web, which distribute images to many different types of displays. An image that looks good on one brand of display might have the midtones too bright or too dark on a different brand, because of the difference in the displays’ gamma settings. Lack of gamma correction also affects color hues. Darker fleshtones are a common manifestation of failing to calibrate the gamma of displays properly.

Macintosh systems will usually display images with greater faithfulness than PCs if they are calibrated carefully, because Apple’s Colorsync technology, Adobe’s Gamma control panel, the Displays control pane and various utilities and applications all work seamlessly and consistently together. Apple systems will usually display images a little brighter than PCs.

The image below allows you to directly estimate the gamma of your display system. Stand about 2 metres away and decide which column of the image comes closest to having equal brightness in the top and bottom halves. The number under this column is the gamma of your display system.

As mentioned above, display gamma can have a major effect on the color hues of an image by changing the relative intensities of the red, green, and blue channels in a nonlinear fashion. Lack of gamma correction is probably the major cause of color shifts between different displays.

The images on this site were corrected on a monitor with a gamma of 2·2 and a white point of 250. It is best to view them with the same settings. If you don’t have a 32-bit color display or you can’t set your monitor gamma, at least try to set the ”picture” and ”black level” controls the best you can. Your picture quality in general will benefit.

These two controls are sometimes called Contrast and Brightness, and those labels are still found on many television sets. Unfortunately, those names are misleading with respect to their functions.

The icon on the left indicates the Black Level control, sometimes called Brightness. This control should be adjusted so that black picture content displays as true black on your monitor. Misadjustment of this control is the most common problem of poor quality picture reproduction on computer monitors, video monitors and television sets.

The icon on the right indicates the Gamma control, sometimes called Contrast. It affects the intensity that is reproduced for a full white input signal. Once Black Level is set correctly, Gamma should be set for comfortable viewing brightness.

If both Black Level and Gamma are set correctly you should have pure black on the left side of this last image and pure white on the other side. Be sure that only the first box appears true black and that the second already represents a dark grey. On the other side, only the last box should appear as pure white.

Then you can adjust the color balance to get a neutral grey, without any color cast. Taking the time to calibrate these controls correctly will ensure you see David’s images as we did when we color-corrected them for your enjoyment.