Color Management System (CMS)
Optoma provides a primary and secondary color management system on the Optoma HD8600. The CMS has the usual ability to separately adjust each color. We do not normally do a CMS calibration, and achieved excellent color without doing so, with the HD8600.
Most likely this is part of Optoma's Brilliant Color implementation. It's mostly like dialing up the "pop and wow" of the image. This feature can be really nice, but, like most dynamic features, takes a toll someplace else. You want the more dynamic look, you also get a slightly less natural look. That's a typical trade-off. Compare the two images immediately below. Same exposure, first one has Pure Color off, the second, has it set to 2, which is very moderate. Study them if you like. Look at the diplomat's upper left forehead - you can see how the lighter areas are lighter still with it on. Mostly though, having it on gives more punch, if you have the image looking great with Pure Color to off, then turning it on is a little too much for a purist. In most cases, I find settings of 0 to 2 to be perfectly acceptable for most content.
Interchangeable Lens System
Choose between two zoom lenses - the standard lens, which most will use for ceiling mounting, a longer zoom which will primarily be used by those rear shelf mounting, or a fixed wide angle lens suitable for rear screen setups, or very close, front ceiling mounting. The lenses use a bayonet mount and easily snap in. You can get the projector with any of the three lenses. It's $7499 when ordered with the standard lens and $1000 or $1500 more when purchased with one of the other lenses.
This feature looks like it's dynamically affecting contrast, and perhaps gamma. Crank it up and you definitely can see skin tones start looking a lot less natural (too contrasty). This is another dynamic feature you can play with, to use as needed (or preferred). And like most of them, you are altering the image, not just "improving it". I recommend moderation.