The ICC profile: colour space translator

When the colour spaces for the devices: camera, monitor, and printer have been measured and are known, a computer program can be used to make a computer file that links the colour numbers for the device to the colour numbers in the device independent colour space.

The computer file that has the information to translate from a device colour space to or from the device independent colour space is called a device profile.

A camera profile has the data to enable a translation of colour numbers from the camera to the device independent colour space.

A printer profile ¹ has the data to enable a translation of colour numbers from the device independent colour space to the print colour space.

A monitor profile has the data to enable a translation of colour numbers from the device independent colour space to the monitor colour space.

In practice, the device-independent colour space is usually Adobe RGB, or ProPhoto RGB. Whatever device-independent space is used, it has a precise set of number triples representing each visible colour. Additionally, whichever device-independent space is used, equal values for red, green and blue, define a tone of grey.

The detailed translation to and from the device independent colour space is done by the colour management system (CMS) within your computer’s operating system. In Windows this is called ICM (Image Colour Management), in Mac OSX it is called Colorsync. So-called “ICC aware” photo applications such as Photoshop, Photoshop Elements, Lightroom, and Aperture give you, the user, the opportunity to orchestrate these colour translation processes and ensure accurate prints every time.

Device profiles (think ‘translators’) are sometimes called ‘ICC profiles’ because of the consortium that invented the way they are standardised.

The idea of using a standard device-independent colour space, with manufacturers making translators to and from this space for their devices, was invented by an international standards organisation called the ICC (International Color Consortium). ICC was started by Adobe, Agfa-Gevaert, Apple, Eastman Kodak, and Microsoft, all companies with an interest in colour compatibility across systems. This idea is at the heart of colour management.

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