Because they're designed for mounted prints. Take a 12"x8" print, put it in a 2" mount, and your mounted print is 16"x12". QED.Whilst we are on the subject of frames. Why can I never find 18x12 frames off the peg? I though 3:2 was a popular landscape format?
16x12, in every shape and colour, but alas, not an 18x12 insight.![]()