Hi crafty, Make sure that you actually have something in the translucency channel - subsurface scattering will not activate the translcency capability. In the image above, I duplicated the color channel into the translucency channel. "Light through Transparency" does need to be selected. This particular example does not use Global Illumination and has no actual transparency in the Transparency channel. However, for GI, make sure that you check both Transparency options 1) in the Raytracing Pane, and 2) in the GI pane of the Render Room.