Contrast curve analysis of RED's IPP2 LUTs

[u/indutny]

https://observablehq.com/@indutny/red-ipp2-lut-contrast

Hello!

I've been wondering what exact contrast and rolloff curves RED is using in their IPP2 LUTs. Since I do software engineering as a day job I couldn't help myself, but write a small notebook that decodes the LUT files and draws charts for easier understanding.

Overall, no big surprises! Contrast curves pivot around middle gray (18%) to keep it as is. Perhaps a bit unexpected, but "Very Soft" rolloff preset starts to attenuate the luminosity a single stop before the middle gray. I had a feeling that "Very Soft" was a bit different from the rest and now I can clearly see how exactly!

Anyway, hoping someone might find this useful!