Why use ICC v4 profiles?

ICC recommends the use of profiles made according to the v4 specification in place of the older v2 specification, as it provides better support for consistent results in open, vendor-neutral, cross-platform color management systems.

Benefits that users will see with v4 are:

More consistent and accurate colorimetric intent transforms resulting from a fully-defined media white point and more consistent handling of black points
More consistent and higher quality perceptual intent transforms because there is now a fully-defined perceptual reference medium dynamic range and gamut
Smaller and more accurate profiles that make use of new efficient transform structures
Generally improved consistency between different profiles and CMMs as a result of improvements to the specification throughout
Better support for re-purposing and proofing of images rendered with the perceptual and colorimetric intents through more accurate inverse transforms

V4 raison d'etre to enable intelligent CMMs and improve results for non-linear color spaces contains the V2 - V4 technical changes and benefits list.

More information on the v4 specification and the advantages of v4 is available.

While ICC recommends the use of v4 profiles wherever possible, it recognizes that v2 profiles continue to be used in some workflows and can give good results. Some recommendations on making v2 profiles are provided for developers.

In PDF/X workflows, Ghent Work Group Process Control subcommittee previously recommended restricting ICC profiles in PDF/X to those made to the older v2 specification. The group is currently testing the use of v4 profiles in real world PDF/X-4 workflows. See a summary of progress and details of how to participate in the GWG tests.