I have been searching for techniques for this effect and have so far not been successful. I'm making a man's torso cake in all buttercream. I've used smashed cake balls to form the abs and pecs and covered the whole cake in a flesh covered buttercream. I've seen this cake done in fondant and then airbrushed around the abs/pecs for shadowing effect. My question is, can I get this same effect using buttercream with no airbrush? I was thinking shading my buttercream a little darker and ice the crevices? Or would painting with color/everclear be an option. It is 3d so you can it does kind of create it's own shadow, but thought if I can figure this out, it might just give it an extra pop! Anyone ever tried it?
both of the options you mention are a possibility
test the painting first on a crusted bit of icing
but you could just use a little powder too
maybe even cocoa powder
maybe cocoa powder cut with confectioner's sugar? i don't know if that would work but i know plain cocoa works
test whichever of these ideas appeals to you--don't just splash it all over your hard work--test it first