This is mostly about curtains than anything else but it is a non-critical factor that is a lacking when realism is concerned.
Currently curtains completely block light and make it a hassle for players who would like to keep their curtains closed and craft at the same time without turning on a light inside while it is day. I very highly doubt every curtain in the game is made from a woven material that doesn’t let any light through, so I propose that curtains be permitted to allow some light through(based on the intensity or proximity of the light source) in order to light up the inside of a place while still blocking off direct visual contact.
This would go both ways, so if enemies were attracted to light and could see it then they’d go to the curtains letting some light through at night from whatever light source is inside. A player would be able to tape over or paint curtains in order to cancel out this effect and if a painted or taped curtain is taken off a player would receive a painted or taped sheet for use in covering a light source or whatever else can be thought of.
If this is applied to curtains, then it could be applied to other things like tents as well.