Rendering intent.

The setting that decides how colours are handled when an image is converted between ICC profiles and the destination cannot reproduce all of them (see gamut). The ICC specification ICC.1:2022 defines four: ICC-absolute colorimetric, media-relative colorimetric, perceptual and saturation, and says the colorimetric intents "preserve the colorimetry of in-gamut colours at the expense of out-of-gamut colours" while "the mapping of out-of-gamut colours is not specified" (clause 6.1). It calls the perceptual intent "most applicable for the colour re-rendering of natural images" and says its rendering is vendor specific, typically with tone scale adjustment and gamut reshaping; the media-relative colorimetric intent is "appropriate when mapping of the source medium white to the destination medium white is desired, but a full colour re-rendering is not". The saturation intent usually "involves compromises such as trading off preservation of hue in order to preserve the vividness of pure colours", and the ICC-absolute colorimetric intent is "most appropriate for a proofing environment" (introduction, 0.4). The intent is the policy side of gamut mapping. The print platforms read for the colour guide do not state theirs: Printful names its proof space, PSO Coated v3, and no intent. A conversion left on the application default can clip saturated blues and greens differently from the proof the seller approved.