Help converting dcp to icc using dcamprof

I’m trying to use dcamprof to convert a dcp file (from Adobe Raw). I’ve tried the following steps:

dcamprof dcp2json input.dcp output.json
dcamprof make-icc output.json output.icc

However the resulting icc seems to be invalid (file size is about ~500 bytes). What am I doing wrong?

Hey

That’s too little info to go by. File size is not a good indicator of whether it’s valid or not. How is it invalid?

You could also try make-icc:
https://www.ludd.ltu.se/~torger/dcamprof.html#make-icc

Darktable says it’s unsupported. A similar icc I created using the dcp2icc in the past is about ~216kB, so the size difference is quite large.

I tried using the make-icc (as I put in the example above). I also tried using the json2icc which didn’t generate a vaiid icc as well.

A while back, I made some ICC profiles from Adobe DCPs, my Neutral file made a 524-byte ICC, Vivid made a 224-byte file. My guess is that there are LUT TRCs in them. Open the .json intermediate file with a text editor, and the contents are easily discernable.

I’m not at my regular computer to check, but IIRC the roadblock I ran into was the DCPs did not contain a ForwardMatrix, which is what dcamprof expected to see to populate the color primaries. At that, I gave up and went back to my Argyll-produced profiles, but I plan to restart that investigation now that I’m retired (sort of…)

Edit: My Argyll-produced camera profile is only 3.5kb, so a usable profile doesn’t have to be big…

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I’m still trying to get it to work. Now darktable loads the icc (I’m not sure what changed), but still something seems off. I’ve tried converting both a Standard dcp and a Vivid one. Both resulted in the same icc. Kind of weird.

The json indeed has a lookup table, but it seems much bigger than something that can be represented in 500bytes.