At work, I am trying to see a very weak reflected light beam so I have
to make the room very dark. Even with no windows this is really
difficult. The number of LED indicators on things is amazing. I have
been crawling all over in the dark with black electrical tape covering
them up. EVERYTHING has them. Outlet strips, chargers, any piece of
electronic equipment has many, computers are nearly impossible to make
dark. I ffinally decided to cover everything with aluminum foil.