The optical transmission properties of acrylic glass is excellent. It's value is about 92 compared to 90 of float glass.
[1]
The air or "dry" side optical performance demanded of the windows in an aquarium is similar to that of picture windows in stores or residences (except that minor wet side distortions are corrected by the interference with the water). A well-finished acrylic panel of any thickness should allow, without any difficulty, the reading of typewritten text of the size
7 lines per column inch (7 lpi)
and
16 characters
to the linear inch (16 cpi or 16 pitch)
located 50 cm behind the panel in air. To achieve this performance, the surfaces shall be polished, smooth, without obvious surface irregularities in the form of waviness, ridges, pits, dimples, bumps, scratches, or scruffs.
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