Opaque is indeed no transmission.
Translucent is transmission with light being scattered so that form cannot be seen, such s frosted glass.
Clear means al light passes straight through with no scatter.
Colour means some parts of the spectrum of visible light is absorbed and some passes through or is reflected.
A coloured tint is when some part of the visible spectrum is transmitted, like sun glasses.
IR receiver lenses are normally a dark red tint with quite low transmission of visible light, but good transparency of IR light in the required wavelength band, but they could be clear or opaque at visible light wavelengths either by the natural colour or opacity of the base resin or by an colour od dye or pigment that is still transparent in the required IR wavelength band.
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