Standardizing a null (non-op) CLF

Since a CLF requires at least 1 processNode, what should be its contents when no transformation is desired, but where it makes sense for a CLF to be present anyway?

I think there would be value in defining a standard null CLF, perhaps by using an agreed-upon ACEStransformID that indicates a non-op. This would be useful as a way to avoid doubt, especially in cases where CLFs are batch-generated as sidecars (e.g. per shot, dailies, VFX plates, etc.).


That does make sense. I can see there being situations where a CLF is needed for every clip, but for some there is no transform to apply. But I wonder if a special ACEStransformID is needed. An identity matrix is probably the smallest, non-clamping, easily identifiable pass-through operator. Perhaps it could just be specified that this should be used where a null CLF is needed.

Yes, any suitable pass-through operation could be used. Wouldn’t it still be useful to have an explicit indication that the pass-through is the intended operation?

In practice with batch-generated CDLs, I find that when some CDLs have nominal values it often raises questions downstream:
“Did they forget to send the correct CDL?”
“Are we sure there is no grade for this shot?”

I’m not sure that an identity operator on its own is enough to avoid that doubt. Perhaps we could use a standard processList description or a reserved id string.