somewhat easier solution is to get a "black light" out of your attic from
when you had all of those black light posters in high school...they transmit

I don't think that would work. A black light transmits both in the visible
light and UV frequency spectrums. Each frequency is attenuated, reflected, or
absorbed differently by a material.

If you see light coming through the trailer when shining the black light, all
you can deduce is that the visible light transmitted through the trailer,
nothing about whether the UV.

Jim Vincent
N483SZ
illspam