Gamut mapping describes the process of calculating the gamut of an image or a device and the mathematical calculations or rules required to convert images from one gamut to another.
Conventional ICC profiles generally offer four varieties of gamut mapping:
- Absolute Colorimetric intent
- Media-relative Colorimetric intent
- Saturation intent
- Perceptual intent
There are two important issues to keep in mind when using an ICC profile's gamut mapping.
Firstly, the ICC profile gamut mapping doesn't control the whole process if you convert an image from RGB to CMYK. It only controls the conversion to or from the Profile Connection Space (PCS). So a conversion from RGB to CMYK will involve two conversions and two profiles: RGB to PCS, PCS to CMYK.
Secondly, both the saturation intent and the perceptual intent gamut mapping is vendor specific – meaning that the method of dealing with out of gamut colours is entirely down to the profile builder and there are no guarantees that the methods that they've used will be sympathetic to your images.
We offer two solutions that can improve image quality.
Source profile to destination profile gamut mapping The source profile and destination profile are analysed and a device link profile with a custom gamut map is built to enable the best possible conversion from source to destination. This profile may be re-used whenever images are converted from the same source to the same destination.
Source image to destination profile gamut mapping The original image and destination profile are analysed and a device link profile with a custom gamut map is built to provide the best possible conversion from that specific image. The is image-specific and usually deleted after the conversion.