It is natural that the built-in wardrobe of Prague, used as a large-area library, will not impress visitors if the sliding front cover door is made of opaque material, does it? You will leave the library with a door of glass, perhaps slightly coloured but transparent enough, not only to conveniently find your favorite pedigreme, but mainly so that the visitor immediately saw the well-preserved seventh edition of Comenius Didactica Magny, recently acquired in a small Dutch antiquarian bookshop.
What to stay hidden
On the other hand, you will not be able to get a section in the transparent door where your wife's favorite fetishistic cloths are to be hung right next to your favorite dimples, whip and leather cuffs with carabiners. There will be better to throw some glass opaque Matelac, or Lacobel, possibly laminated board.