Creatives won’t want to see a flat looking image designed to capture high amounts of detail at the expense of looking pretty. For that reason a DIT will perform a base color adjustment so that what everyone sees looks useful. There’s much more info in the color section on this, but here’s the gist:
DIT gets the camera output via wireless transmission and normalizes it, plus adding the CDL (color decision list) on top. DP tells DIT what they want creatively and DIT applies it. DIT takes screen shots of on-set color decisions to communicate with post. This can be helpful as it’s an immediate visual of the look which might be lost or ignored in the CDL.
CDL is a specific type of LUT
Abelcine: “The American Society of Cinematographers (ASC) saw that there was a huge variety of LUT formats out there, which created a lot of problems between on-set tools and postproduction. So they came up with a standard they call an ASC Color Decision List (CDL). This is a 3D LUT with a relatively simple format. Most color-grading software applications can load an ASC CDL file, and many on-set tools can work with these files, so the ASC CDL offers the clearest solution for working with LUTs on set and in post.”
DPs usually combine the CDL with a LUT for a specific look as the CDL has a restricted set of parameters that can be changed. It’s basically primary corrections (slope, offset and power) and saturation. Similar to LUTs, you don’t get secondaries or any kind of spatial adjustments. CDL information is software agnostic, meaning it should reproduce in any compatible device or environment.
Red and Arri cameras allow you to predetermine “looks” in their own format. It’s similar conceptually to a LUT but brand-specific. The nice thing is, the look can easily be recalled in color with no more than a right click.