Oddy test results for felt

Lindsey Tyne <ltyne [at] themorgan__org> writes

>A curator has recently asked if felt (wool or synthetic) can be used
>inside exhibition cases. We Oddy test all materials prior to
>installation in our exhibition cases and we will carry out tests on
>a variety of felt options. Has anyone used the Oddy test to assess
>felt for use in exhibition cases? If so, what were the results?

All woollen felts will fail the Oddy test with silver due to sulfur
containing amino acids in the wool, about 20% fail with other metals
as well.  Synthetic felts will be a better approach, but colour may
be an issue.  We have tested a lot of cotton velvets, the cotton is
generally inert, but dark dyes (blue, red, green, black) often
contain sulfur and will fail with silver. We once tested 28 cotton
velvets in these colours, before finding the 29th passed.

David Thickett
Senior Conservation Scientist
National Collections Department
English Heritage


                                  ***
                  Conservation DistList Instance 26:2
                  Distributed: Thursday, May 31, 2012
                        Message Id: cdl-26-2-004
                                  ***