Making connections with iccMAX
iccMAX profile connection Connecting with iccMAX
Next: PCS Conversion and/or Adjustment
Connecting using iccMAX / V5 ICC profiles
More complex colour management scenarios are possible with iccMAX profiles defined by the ICC.2 and ISO 20677 specifications. The iccMAX profile file format uses the same general structure as V2/V4 profiles but defines V5 profiles. The iccMAX specification introduces several new tags and tag types, and extends the MultiProcessElementsType tag type to provide greater flexibility in transform encoding. However, for the most part, connection using iccMAX profiles can be thought of as just an extension of the connection concepts described above for V2 /V4 profiles. Transform selection and PCS Conversion / Adjustment are still the key aspects of connecting with iccMAX profiles. However, significant extensions of these concepts are introduced to allow for a wider variety of colour management scenarios to be accomplished.Transform Selection
Transform selection for iccMAX profiles uses the same parameters discussed for V2/V4 profiles above: profile class, position, rendering intent and transform type.
Although the concept of transform type exists for V2/V4 profiles it is in practice largely assumed to be defined by the profile class for most implementations (with no separate selection option of transform type by the application). However, for iccMAX workflows (especially those defined by Interoperability Conformance Specification (ICS) documents) the use of transform type becomes critically important to differentiate and select between workflow scenarios. In some ICSs, only one transform type is defined and thus allowed in conforming profiles. In other cases, transform type selection precedents and rules are defined by the ICS.
Because transform type selection allows for multiple scenarios to be involved with a single ICC profile, applications that support iccMAX workflow scenarios may require additional UI related to transform type selection to feed into CMM control options that control transform selection.
(Note: A discussion of transform type selection in terms of CMM control options can be found in annex K of the iccMAX specification). The set of transform types that can be encoded in iccMAX profiles is different than what can be encoded in V2/V4 profiles, and they all generally have two flavours that specify either the use of a colorimetric or a spectrally based PCS. Both colorimetric and spectrally-based transforms can be present in a single iccMAX profile, so transform type selection is very important for obtaining predictable results.
The colour LUT transform type identified previously for V2/V4 profiles can more correctly be referred to in iccMAX profiles as a colorimetric colour transform type with transforms that utilize a colorimetric based PCS. The tags associated with the colour MPE-based transform type in V4.3 have been repurposed in iccMAX to define a spectral colour transform type with transforms that utilize a spectrally based PCS.
(Note: The preview tags were deprecated in V4.3 as well as in iccMAX). Additional iccMAX transform types have different transform endpoints than simple Device and PCS channels. These additional transform types are used in more advanced colour management scenarios, and, in most cases, they also have both Colorimetric and Spectral flavours. These more extended transform types in iccMAX profiles include: BRDF parametric, BRDF sampled, directional, and multiplex channel-based. The multiplex channel-based type will be discussed further below. It is recommended that the iccMAX specification be consulted related to the other more extended transform types.