Wife's in the midst of authoring a historical fiction. Thought I'd give her something relevant to look at when contemplating, rather than staring at the squirrels...
The lithophanes show well from early dawn to late dusk. During the night they act as a partial curtain.
Material is Poly Cutting Board by Sabatier, 12" x 18" x 0.25" (~$ from Lowes. Two small screws and 30lb fishing line are used to hang them from the latch.
Jon