Well I guess my original question was not an issue. Thanks.
Seem to have started a hare, though. Once in my school days I painted a darkroom flat black. Never again. It was so gloomy. I want light and lots of it, safe when that's needed, otherwise white light. Good points about enlarger leaks, though. Mine is quite well behaved, but a flat black section around it would be a good idea. This is a new build dedicated darkroom shed, so I can decorate it how I like. No bathroom ducks.