Couple of months ago Igor Posavec (One of the developers of Exr-IO plugin for Photoshop) created a topic at Blenderartist forum:
He mentions there:
One thing that remains is Cryptomatte. Exr-IO can now read and use all Cryptomatte masks in Photoshop - a new way how to edit the artworks. But i don’t get it in Blender. Blender does not write Cryptomatte in the file data structure. It do CM calculations, but it spills it out as image pixeles. You can pipe it in the output channels, but exactly at that moment the whole Cryptomatte concept goes wrong - it produces image and not data. Cryptomatte passes are not only pixels, they need to be stored in a different way. Different from Arnold, Vray, Lightwave (and so on), loading Blender Cryptomatte channels in Exr-IO, in Fusion or in Nuke shows … nothing - at least nothing you can work with.)
I hope some of you professionals here have good connections to developers. One should just ask them to shift Crypomatte from image into data blocks and everything will work perfect (it is there, but on the wrong place)
So, does he have a good point? Can anything be done on Blender side in this regard? That would be amazing to be able to use Cryptomatte in Photoshop.
Oh my this would be so good we could use CM in photoshop. I actually use EXR-IO to bring in multilayered exr data and I think a lot of other people do aswell (as visible in the video).
Masking by objects / materials / random ID is however quite hard in Blender. Right now my solution is to render viewport flat color random and use that however it’s not particularly good data to work with so often colors spill into each other and that’s where it fails.
Cryptomatte from Blender is working in Photoshop with the Exr-IO Plugin. Don’t render the blender passes to an file output node, because then it is not working. But with the main output it works fine. Long ago I opened a blender bugreport but it was ignoredand the problem persists.
See: https://developer.blender.org/T64953
So it is impossible to render many viewlayer with cryptomattes to seperate files.
I was looking for a solution to this problem from the very first day since I have switched to Blender 4 years ago. I understand the benefits of Cryptomatte and different ways of usage. But I wanted just one easy pass with material ID with every render, which I can save to PNG and use in Photoshop. In the end, I have made my own addon called CID. If it could help anybody, please enjoy it.
I understand it. No problem. That’s not exactly the case. I was struggling for years and looked for something like that on any forums. I would be happy if I could find something similar before. Only for help and save many hours. Have a nice day.