So I hate to repeat this thread subject, but the previous one is marked as CLOSED and yet there doesn't appear to be any resolution to this issue.

Does the Background Image parm of a Camera not support op:/ data node references, in particular op:/img/… references? I'd like to simply add a solid color, or maybe a procedural pattern, generated out of the COP2 /img context as the background of my renders without having to litter my hard drive with tiny jpeg files.

I tried putting a simple op:/img/solid_bkgd reference into that parm but when I render I just get an error about unknown file type. Am I typing this reference incorrectly? Or does this still not work properly?

I'm guessing /img/solid_bkgd is a COP2 network… have you tried pointing to an actual COP (say, an output null) within that COP2 net?

Yes, I tried that too:

op:/img/solid_bkgd/color1

…same error message:

Error: Unrecognized file type “op:/img/solid_bkgd/color1”.

hey john

did you ever figure this out? having the same issue

Unfortunately, this still does not work. I've tried it with 18.0, 18.5, 19.0, and 19.5 and it fails in the same way in all of them. I just don't think this is a feature they ever intend to support. Which is strange because the COP2 image appears as the background in the viewport when you look through the camera.