How to apply channel packed RGB image with alpha for masking non-RGB nodes

I’ve used channel packing to produce two .psd files I’d like to use for base color, specular, roughness, normal, ambient occlusion, and an alpha mask that I’d like to apply to the specular channel when applying it to metalicity. Base color would link from the RGB channels of an image whose alpha channel I’m packing with either the mask for the specular texture when linked to metalicity, this to apply the grey values I’ve painted into just the metal parts in a scene (photogrammetry). As is, linking the Texture Sample node to Base color, this mask intended for masking something other than base color is masking base color - how do I fix that?

Secondly, I have this other texture, a .psd with roughness mapped to red, specular mapped to green, AO mapped to blue, and height mapped to alpha. What nodes are then set up in the Material Editor to link these channels to their respective counterpart shaders? And it being my intention to have only that portion of the specular map pertaining to metal parts in the scene applied to metalicity as driven by the transparency mask in the first .psd containing RGB info, how can I link that alpha channel to the texture sample whose green channel contains the specular info I then wish to link to metalicity?

If assigning the channels differently among these two .psd files is necessary, it’s no issue to rearrange them in Gimp. Much appreciate any help, especially if there’s already a screen capture of the material editor showing something similar to this out there, which I’ve yet to find.


  1. Use a component mask.
  2. The texture sample node comes with separate pins for each channel, so just connect the channel to the appropriate input. For your case, Red->Roughness, Green->Specular, Blue->Ambient Occlusion, Alpha->World Displacement.