Pretty much (there's a bit of Windows at the smaller places) all the big VFX studios (ILM, SPI, Weta, Framestore, MPC, DNeg) are running Linux for almost everything involving content creation, using apps like Maya, Nuke (for compositing), Katana, Houdini, etc.

There are exceptions - some apps (ZBrush) don't run on Linux, so there are Windows machines around, but in general >= 95% of machines the artists and developers use are Linux at the big places.

And most of those apps use OpenColorIO as a framework for handling colourspaces.

It’s mainly in large facilities that run huge jobs with massive amounts of data. Maya, Nuke, Houdini, Flame, Baselight, many in-house VFX software all run perfectly well Linux. And of course the cornucopia of renderers running on their server farms, as might be more expected.

The lineage is from SGI, where many of these applications were born, but as the company faltered and consumer graphics hardware took off thanks to gaming, Linux became the natural home.