An ICC display profile describes the color gamut of a CRD or LCD monitor, or of an RGB working space (like those used by Photoshop) which can be considered as "ideal monitor".

The profile of a color monitor converts from RGB to PCS and is two-directional because the monitor can be a source device (e.g. when converting from monitor to printer) or a destination device (e.g. when converting from scanner to monitor). There is only one rendering intent.

The display profile can convert to and from the PCS with an alghoritm (matrix profile, from RGB toi XYZ and vice versa) or with a couple of tables, from RGB to Lab or XYZ and vice versa.

Summarizing, a ICC display profile:

• is two-directional, from monitor to PCS and vice versa;
• only one rendering intent is required;
• must be RGB;
• may be either:
  • in table form (in which case the PCS can be Lab D50 or XYZ); or
  • in matrix form (in which case the PCS must be XYZ).

Typically, the monitor profile is in matrix form and contains the following information: three tone curves, XYZ coordinates of the white point (three numbers), XYZ coordinates for each of the three phosphors on the monitor (nine numbers in total). From this informations the conversion from RGB to XYZ and vice versa can be calculated.

Many matrix monitor profiles contain a single number to state the tone curve: this is the gamma of the monitor, and the tone curve is a pure gamma curve. Other monitor profiles contains actual curves, that can have shapes that differ from pure gamma curves, and can be used to solve certain special problems.

The monitor profile can also be in table form. The table converts to RGB to Lab and vice versa. Sometime these type of profile also uses input and output curves on either side of that table.