Light source

Although a Lab coordinate is always specified with respect to a white point, it is fortuitous, or it is as a result that flat art reproduction is generally standardized on the same D50 light source as specified in an ICC Profile Connecting Space (PCS). If a different light source is used or, more commonly, when using an ICC RGB profile with a different native white-point (or “media white”), you must convert between white points. This process is called chromatic adaptation. Selecting profiles standardized on D50 such as ProPhoto RGB or ECI-RGB avoids this and, therefore, the need to support or interpret the required transform. However, there are some other practical limitations to overcome during the conversion of ICC profiles that use a color-space with a different white point, such as sRGB or AdobeRGB (1998).

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