If you’ve ever struggled with OSL—where to put it, how strong it should be, or why it sometimes just looks “off”—this is me walking you through what usually gets skipped. I start by simplifying the problem: what happens to shadows under soft ambient light versus a harder, directional light. That “terminator” line (the transition from light to dark) is what lets one light source read against another. If everything is softly lit, your glow has nowhere to live, so I intentionally place my OSL inside the shadows of my main light. Then we get into the part that makes or breaks it: color interaction and values. I use my Kingdom Death: Novice commission as an example—orange lantern light hitting violet stockings (near complementary) naturally wants to desaturate and die, unless you choose to push saturation for a more magical, neon-like look. I also show how I’ll let the glow travel to less “obvious” spots (jaw, under the nose) to guide the viewer’s eye once the lighting story is established. The big takeaway: OSL is value first, color second—so check it in black and white, and make sure the light weakens as it travels away from the source.