I'm using an .hdr image (from hdrhaven) in a dome light in Solaris. Works as expected with Karma. When I switch to Renderman, the hdr texture channel is blown out (completely white). When I lower the light intensity I can see it but its very faint, almost as if its been clipped/has no dynamic range. Am I doing something wrong or is this a bug?

hdPrman only supports tex/tx format textures. Use the txmake command bundled with renderman the convert the images first. Fortunately, karma now also supports tex images, so you should be able to use one set of textures for both.

Ah, I remember that from many years ago, I didn't realize that was still the case. The domelight page in the docs suggests that you can use EXR, HDR or TIFF images and doesn't explicitly state the need to convert (on that page).

In any case I converted it and its working as expected now, thanks!

the renderman plugin with the RIS ROP (non-usd) will convert automatically. I'm guessing it's todo.