Hello, I’m moving from Arnold and standard surface materials to Karma and salaris and mtlx shaders in Houdini and I’m stuck on how to convert my workflow.

Usually with Arnold surface shaders I plug the rgb mask I made in painter in to an rgb float to isolate its red green and blue channels and then pipe those in to a layer rgb along with the colour correct from my diffuse texture so that I can have more control when look developing.

I’ve attached an image of my template. If someone can point me in the right direction that would be great, thanks! 🙏

I think you might be looking for the materialX separate family of nodes. mtlx separate color4 or separate color3 for rgba and rgb color maps or mtlx separate vector 4 or mtlx separate vector 3 for four and three component data maps. (I don't think strict typing is used in karma so either color or vector will work)