6mm "panda film" is pretty inexpensive on eeb ay.

white on one side, black on the other.

NO light will get through it, unless a seam where it overlapped isnt taped shut.

unless you have help, the 5 foot wide roll is easiest to handle (versus 10 foot wide.

if used on the floor also, and all seams secured, it can turn any area into a "tent".

filter the intake, and never enter area without being perfectly clean, and use "area only" clothing and footwear to keep out the borg (spidermite).

treat it like a laboratory. get a white lab suit for entering your area.