Blue metallic sheen print?

[cyrus]

A friend has a print that her long-deceased grandfather made a bw photo of the sun shining off of water along a coastline. Anyway, seen at a certain angle, the print has a blue-ish metallic sheen to it. It is a bw image, not toned blue btw .What kind of printing is that? I couldn't really tell, since the print was behind glass, but it appeared to have a slight texture to it too. Any ideas? It caught the tonal range of the sun on the still waters quite well.

[Mark Sampson]

That sounds like 'mirroring', a type of image deterioration where (I believe) the silver plates out on the suface of the print. Hard to say without seeing the print though.

[Glenn Thoreson]

Sounds like mirroring to me, too. Pretty common on old prints.