I'm looking for a word, could be a noun or verb or adjective, that describes something with varying degrees of opacity/exchange/transfer, possibly that could be controlled. An example that comes to my mind is, 'aperture', which could be opened or closed to either allow light/exchange. Or 'veil' which could either hide or reveal.
Thank you for your answers! I think 'filter' is quite nice. To clarify, this is for an architectural concept. I'm looking for a one-word marketing-style concept for my project. I will be designing a gay space (a sauna) that challenges societal norms relating to sexuality and private/public by exposing some of the program to the public at varying degrees at different parts of the building (through varying glass opacities, etc)
Hopefully that makes it more clear what I'm trying to achieve.