I gave up. The light source kept bringing out some weird red colors. I'll try again on another drawing, since what I'm working on now was more of a priority - trying to make red coals. I wanted the GI by itself to light the object in my coming picture, but it didn't happen as I planned. I'm improvising with a low sunrise. I haven't actually given up on the idea of using another light source, but it will just happen later.