Fluorescence

Maria Brunskog <curare.brunskog [at] spray__se> writes

>On microscopic examination of cross-sections sampled from aged,
>japanned surfaces on furniture, a bright and saturated red
>fluorescence colour has been observed. The light was in the lower
>UV-range, 330-390nm. At a higher UV-range 430-450nm the fluorescence
>was not visible. The red colour (like good quality wine) has been
>interpreted as silver. I would appreciate any comment from anyone
>with experience of metal/silver fluorescence, either from metal
>foil or powder incorporated in lacquer media.

I do not know what silver metal would look like under these
conditions; however, I have not seen this in examinations of metal
objects in ultraviolet light. Mineralized silver might have a
characteristic fluorescence. As I recall cuprite (copper oxide)
appears bright red in uv light.  Madder (red lake) also  fluoresces
a bright red under ultraviolet light. Could a red glaze have been
applied over a metal foil?



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                  Conservation DistList Instance 14:65
                   Distributed: Monday, May 28, 2001
                       Message Id: cdl-14-65-004
                                  ***