Scott: A few observations and suggestions...do test. I think you'll find it doesn't make any difference. But if it does, I have found a 3M product very handy for totally stopping light from seams/joints which don't need to move. It's called autobody clay and it is black clay used in autobody work to fill joints. It comes in strips about 1/8" wide. It was very useful to stop massive leaks when I converted a B22 to a cold light. It scrapes off easily, which is more than I can say about silicone sealant. It really sticks to anything. For light skirts as discussed in previous posts, bicycle handlebar tape is very useful. Lots of these are adhesive backed on just one side of the tape, so they make good light skirts if you put them on just right. If you put it on just right, the unstuck side toward the negative carrier, for example, it will just touch and shut out the light without enough being there to fold under and cause a fit problem. Finally, painting the darkroom walls, ceiling, etc. makes sense but if you're enlarging wearing a light colored shirt the biggest source of stray light is you, because it reflects off you and you're the one standing right over the paper.