The Rabbit Hole

Bear in mind that albedo is linear, and closer to stops. So 16.291 has no real 1:1 relationship with reflectance.

The secret is that the three lights are unequal in terms of how luminous they are. Greeny yellows are far more luminous than reddish and reddish is far more luminous than blueish magentas.

@Mareck Every single imager that has grabbed onto the concepts thus far has initially struggled thinking that their materials are broken, because of course, they look "sort of fine" in sRGB.

(in the case of a 1D LUT, either the RGB triple looks up each value in a single table and gets a value back, or each of the three values goes in from RGB and each value is looked up against its own 1D table.)

And that is all Look Up Tables are, they look up one value and output the resultant value (1D) or output all three values (3D) based on that single input.

If you wrote a function that was based on the assumption that the values were between 1.0 and 14.0, and someone fed values from 0.0 to 3.0, the output would be entirely wrong.

The View is the basic curve

All colour operations, from transforms on to corrections, must be applied on unassociated alpha RGB values.

As you probably have seen, grading should be considered a separate creative act. That is, grading a shot is separate from lighting the shot.

It's very rewarding watching people get flipped upside down and then land with a much better grasp of what is going on and the importance of the details.

@OldMan In terms of "best format for renders" it is unquestionably EXR.

A great way to think of alpha is that the type of alpha used determines the operation used to composite. Also remember, that only associated alpha represents both emission and occlusion. This is precisely why raytracers and other such things can't render any other type of alpha; only associated alpha has a representation that matches our reality.

The bottom line is very simple: Never, ever, under any circumstance, ever use unassociated alpha. You should never need to hit convert premul. (Unless you are damn well aware how you generated your alpha and RGB values)