Yesterday i found an intriguing plate with an additional glass sheet glued on top of the original negative. The reason Acsinte made this weird assembly is unknown as the original picture carrier is in perfect state: no cracks in glass or anything. And even if he was trying to protect the original, he should glue the second glass on gelatine side, making some sort of sandwich (glass-gelatine-glass) which is not the case.
The only reason i can think of is he needed a special effect for that picture, sometimes referred as veil consisting of multiple images that forms on top of each other, due to multiple glass-air or glass-glass surfaces on which light bounces/reflects.
Here is the scan made with and without the extra glass plate glued on top of the original one (glass-glass-gelatine):
Do you have another explanation?