What are Shadow Box frames?  This post "Our five most popular shadow box frames questions"  will address this and other questions.  These specialized picture frames are essentially the same as normal picture frames but with several different features.  Firstly the moulding, or frame, is much deeper at its side. For instance a normal moulding could be 4cms wide x 2cms high. With shadow box mouldings the proportions are reversed so that it would be 2cms wide x 4cms high, thus giving frames that ‘boxy’ look.

As the frame is deeper, and since a window mat, glass and backing are quite thin, perhaps making up .5 cm of the ...