Nuke Studio color problems


Hey everyone,

We have some LogC footage from an Arri Alexa Mini. It was given to us in MXF and we transcoded to ProRes 4444 using ArriConverter.

Then we used Nuke Studio 9.0v5 to conform and export everything to EXR.

Our color workflow consists of exporting everything we need to EXR in RAW, meaning we don’t want any color transform inbetween. We then use OCIOCDL in Nuke to do a previs grade and before writing our final comp work we use the same OCIOCDL node in reverse mode so everything goes back to RAW for final grading.

Problem is when we set everything in NukeStudio to raw (Input Media Colour Transform and Export) it somehow introduces changes to color somewhere we haven’t been able to find. Easiest way to prove it is when we import that same ProRes file in NukeX, set it to read raw and write an EXR from there, data is kept untouched (which is what we want).

How can we make NukeStudio export RAW without introducing changes to data? Is there something we’re missing or doing wrong?

Thanks in advance!

PD: Reads in attached image: 1. ProRes 4444 from Alexa. 2. EXR written from NukeX. 3. EXR written from Nuke Studio