[Tig] LUTs compared to grading linear

[TSassoon at aol.com]

In a message dated 7/23/06 6:32:14 AM, judgedave at mac.com writes:

> Currently I skip the LUT stage I scan in LOG then grade in linear straight 
> away. I hope this is not a bad idea. If someone knows that I will end up in a 
> dead end I really appreciate your input.
> 


If it's linear float that you can recover greater than 1.0 values, then fine. 
Integer linear, even a single step that truncates, you have a problem. Pretty 
easy to check - blow something out, then see if you can recover the 
highlights downstream.

Rather than using the canned default log to lin LUT (which can be harsh), why 
not make your own? Take an approved sample filmout print (probably of Marcie 
or other sample image), tape it to your CC monitor, put up a bit of white 
behind it, and CC the digital source of the image to match. Called a closed-loop 
calibration.

IMHO log is a better way to integrate linear digital imagery into a film 
workflow - one can better judge color response and better predict output, at the 
cost of less accuracy in mixing overlay images. Log is also less prone to black 
point color errors (from high gamma viewing).


Tim Sassoon
SFD vfx & creative post
Santa Monica, CA



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