The purpose of the AIM site is to provide help in setting up an accurate desktop image manipulation system for digital photographic images. AIM contains currently (about) 212 pages and is 100MB in file-size.
Please do not adjust your calibration nor decide you calibration tactics based on the introductory illustrations on this page. This page is just an introduction and the proper calibration tactic depends on if the system is ICC color-managed or not.
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The
below filmstrip is not pure black, there
is a colorful welcome message on it.
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| The message utilizes that portion of the intensity range that is sometimes called as the "gamma benefit", "better range", "better shading of shadows", or "the best bits". You can not see the welcome text with a native PC system (that is not gamma calibrated) because this "better range" is deep down in the scotopic level (night adapted vision) of the eye. |
 Illustration, not for calibration purposes. |
Transfer function differences somewhere in the digital imaging workflow are the most common reason for image quality problem. Very large errors are created when gamma compensated images are enhanced, please have a look at the image-gamma induced errors section.
In linearly calibrated system (gamma 1.0) the gamut is properly balanced. Digital colors are based on the tri-stimuli theory, all the colors or hues are produced by summing the primary colors in varying intensity. The tri-stimuli theory is linear, the sum of the primary colors is only correct on linearly calibrated (gamma 1.0) system.
In addition to the large adverse affect to color or hues the gamma also changes the intensity scale. A steep gamma space makes the highlights perceptually very coarse while wasting the available digital gradation at shadows tremendously.
The above gray shading graph illustrates the intensity range problem. High gamma spaces like the 1.72 of an uncalibrated Mac system, 2.2 of the sRGB specification, 2.5 of the native PC system and the CIE Lab space all waste the digital codes in the deep shadows while making the gradation at highlights very coarse. Gamma space 1.25 provides the perceptually uniform coding (all the steps are visible and equal by the perceived change of lightness). Gamma space 1.0 provides the same perceptual effect as the camera f/stops.
If you use Photoshop or any other image editing software that allows to edit images in a gamma space do take a look at the Perceptually Uniform Coding -page you can accurately evaluate the so called perceptually uniform gamma space easily using the AdobeGamma or some other utility that can adjust the viewing gamma of the system. The Perceptually uniform gamma space is not the "Windows default" nor the "Mac default", that are the two default choices the AdobeGamma gives you. But why is there not a choice called "Perceptually Uniform" in the AdobeGamma?
Please note that the display systems needs to be in 24 bit True Color or better mode if calibration is done according the guidelines described here. Before you change the calibration setup of your system please read all the related pages here.
Accurate Image Manipulation for Desktop Publishing