You, sir, are my new best friend. The key was the inheritance issue you described. Once I put values into the transparency, refraction, etc. for the label, everything started to fall into place. In fact, after some tinkering I discovered as you can see that Carrara did honor the alpha channel in the PNG texture, and I was able to eliminate the opacity mask altogether. This may be partly due to the fact that I am applying the label to a shading domain, not to the whole object. I don't really know - there are still some grey areas in this process for me. I also turned on "premultiplied alpha" in the texture map, which gives the ketchup smears on the glass a nice thinned-out edge. Thanks very much for your help. - Joe