PSA: black acrylic is opaque to visible light, but transparent to IR - so a bit of that will nix the light but not the IR. It's actually pretty interesting to

PSA: black acrylic is opaque to visible light, but transparent to IR - so a bit of that will nix the light but not the IR. It's actually pretty interesting to look at the world with an IR camera (e.g. Pi NoIR) - red wine looks like clear water, black actrylic looks plate glass, black t-shirts appear pale.