Fatty acid bloom

I am dealing with an 18th century carved wax plaque exhibiting fatty
acid bloom which is visually extremely distracting, though
restricted to specific parts of the carving.  This is not an unusual
phenomenon and removing the bloom is no particular problem.
However, the bloom on this particular object reforms within a few
months of cleaning.  The plaque has been stored and displayed in
various conditions of RH and temperature over the last 25 years,
sometimes very stable at 50% RH and 20 deg. C, sometimes more
variable, and recently on loan experiencing very low RH and up to 26
deg. C.  The bloom seems to recur quickly in all conditions.

Various published articles indicate the likely mechanism and cause
of the formation of the bloom.  What I have not come across, is any
suggestion of how to prevent recurrence.  Does anyone know or have
any ideas on this?

Tracey Seddon ACR
Senior Organics Conservator
National Museums Liverpool
Midland Railway Building
1 Peter Street
Liverpool L1 6BL
+44 151 478 4843


                                  ***
                  Conservation DistList Instance 29:11
                  Distributed: Tuesday, August 4, 2015
                       Message Id: cdl-29-11-012
                                  ***