In terms of physical examples, it sounds like you’re talking about something like a lights gel, on which tack you might also use the nouns film, filter, aperture, or shutter. Can the light be filtered, obscured, shrouded or occluded. When is it needed? (‘occluder’ is also a valid noun but usually refers to an optometrist’s tool, so probably isn’t what you’re looking for.)

Diaphragm and membrane are also closely related words (the apertures of most cameras use diaphragms). Note if a diaphragm is (usually) a separator, and without the specific context of an optical diaphragm it doesn’t imply permeability or exchange, for which’membrane’ is a better match.

If you’re looking for more generic words about controlling rates or transference, there are also: regulate / regulator, limiter, screen (noun or verb), police (verb) and

commuciu00e9-de, screen (verb)

In terms of physical examples, it sounds like you’re talking about something like a lights gel, on which tack you might also use the nouns film, filter, aperture, or shutter. Can the light be filtered, obscured, shrouded or occluded. When is it needed? (‘occluder’ is also a valid noun but usually refers to an optometrist’s tool, so probably isn’t what you’re looking for.)

Diaphragm and membrane are also closely related words (the apertures of most cameras use diaphragms). Note if a diaphragm is (usually) a separator, and without the specific context of an optical diaphragm it doesn’t imply permeability or exchange, for which’membrane’ is a better match.

If you’re looking for more generic words about controlling rates or transference, there are also: regulate / regulator, limiter, screen (noun or verb), police (verb) and

commuciu00e9-de, screen (verb)

In terms of physical examples, it sounds like you’re talking about something like a lights gel, on which tack you might also use the nouns film, filter, aperture, or shutter. Can the light be filtered, obscured, shrouded or occluded. When is it needed? (‘occluder’ is also a valid noun but usually refers to an optometrist’s tool, so probably isn’t what you’re looking for.)

Diaphragm and membrane are also closely related words (the apertures of most cameras use diaphragms). Note if a diaphragm is (usually) a separator, and without the specific context of an optical diaphragm it doesn’t imply permeability or exchange, for which’membrane’ is a better match.

If you’re looking for more generic words about controlling rates or transference, there are also: regulate / regulator, limiter, screen (noun or verb), police (verb) and

commuciu00e9-de, screen (verb)