A while back one dark night in my house I used a 405nm pointer and as I swept it across a white wall, that portion illuminated glowed a pale white for about a second of time; even old white paint from my grandparents hoosier cabinet is photoluminescent. It's not something I expected. I also discovered plaster in my house photoluminescences too. Not something I expected. Curiously, I have some titanium dioxide (tio2) it does not photoluminesce as I recall.