Which Gray is 50% to You?

Open a paint program, and start a new image. Now select a gray of 50% brightness(rgb values 128, 128, 128). Fill your new image with this color. Are you seeing a gray that is exctly in the middle between your monitor's blackest black (0% brightness) and whitest white (100% brightness)? Don't you think you should be? If it is not, you are getting cheated out of some of your available resolution.

Here's a test to see what gray is displayed by your monitor as actually midway between black and white:

Stand back a few feet, turn off the light, and squint just a bit. Which of the images in Figure 2 looks most like the control image, Figure 1?

Figure 1: Control Image

This image is painted with solid stripes. When you squint or stand back from the calibration images, the one that looks most like this is the one you see as midway between black and white.

40%

45%

50%

55%

60%

65%

70%

75%

80%

Figure 2: Calibration Images.

The % numbers here refer to the brightness of the texel color, as selected in a paint program like PhotoShop.

If your answer is 50%, then the paint palette choice is being displayed as you would expect, in the middle between black and white. Your display will give you the fullest range of color depth on your monitor.

If your answer is 75%, then your colors are being displayed much darker than what the paint palette intends. Your gamma value is probably still set to gamma = 1, exactly like it was set at the factory. You are losing a lot of details in the dark.

Calibrating your monitor will bring out the full potential from your monitor display.