LUT and nodes

[Stig Olsen]

Hi,

I did follow your example and made a LUT “AlexaV3_K1S1_LogC2Video_EE_davinci1d.data”, and put it in both cine and arri-folder.

When I then click on the node, I cant find the LUT under the 1d or the 3D, what is done wrong?

[Mike Lary]

Hi Mike,

I read this entire thread before posting, as well as your blog and lot of what you’ve written elsewhere. I appreciate all the knowledge you share. What I experienced with this LUT was behavior counter to what’s been described by others. The culprit is a simple one that people should be aware of. Please note: The source footage was not clipped in-camera.

The symptoms:
1) When the LUT was applied to a node, it would clip (and cap) the highlights around 93% and the shadows around 5%. Any adjustments made to that node would be limited within that range. If I made adjustments to a node beyond the LUT, the full range of data was accessible.
2) When I applied the 1D LUT (no color space), a color space transform would occur that would identically match the color transform applied when using a 3D (REC 709) LUT. This was verified with scopes.

The cause:
Renaming the LUT before using it in Resolve. If the LUT file name is left as-is, it works perfectly. If it’s renamed (in our case, we changed ‘ARRI’ to ‘RED’) it doesn’t behave properly. If the name is changed back, it works perfectly. We verified this on two different systems.

We’re up and running now, but I’m curious as to why this is happening. It seems that Resolve must have been using the 3D LUT (that resides in the same folder) even though I selected the 1D LUT.

Mike Lary
Digital Factory
Seoul, South Korea

[Mike Most]

I’ve never run into that problem and I’ve renamed numerous LUTs. What is an issue is using 1D LUTs, which is why I only generate 3D LUTs when using tools like Arri’s LUT builder. I think I’ve mentioned that in previous posts.

[Mike Lary]

Hi Mike,

I’ll choose the ‘forced’ option for 3D under LUT Parameters, then. Thanks for that information.

Can you clarify why 1D LUTs are problematic in this scenario? It’s my understanding, based on what you and others have said, that 3D LUTs are only required if a color transform is being applied.

Mike Lary
Digital Factory
Seoul, South Korea

[Mike Most]

Technically, that’s true, 3D LUTs are required for color space transforms and any other transform that involves a saturation change. Practically, though, Resolve just seems to prefer 3D LUTs, so that’s what I always use.