Stains on marble

Andrew Thorn <artcare [at] iprimus__com__au> writes

>Eric Miller <eric.g.miller [at] btinternet__com> writes
>
>>We are currently cleaning a marble fireplace that has yellow/brown
>>tar stains that do not respond to our attempts at removal. Laser
>>cleaning works but it turns the marble yellow. (A 1999 DistList
>>entry affirms Synperonic N, but this is no longer available.) Any
>>suggestions?
>
>Thank you for your comments on the impact of laser cleaning on
>marble. Gradually some critical assessment of this wonder tool is
>emerging at last.

I'd like to make two comments:

(1) If a process 'turns the marble yellow' I would suggest that it
does not 'work' in this instance. We have to be careful about the
words we use. Laser cleaning is no different from any other cleaning
technique in that it has to be used appropriately; it works very
well in some situations and not so well in others. If a test clean
shows negative results then the technique does not 'work' and, of
course, should not be used.

(2) For critical assessment of laser cleaning as a technique in
conservation, it is worth trawling through over 30 years' worth of
research and publications. The proceedings from the LACONA series of
conferences (which started in 1995 and have been held every 2 years
since) is an excellent place to start. LACONA 8 will be held in
Rumania in September. Training courses are also available for
conservators wishing to learn more about the technique and wanting
to gain some practical experience. A discussion forum has now been
set up on the web where conservators can post their experiences of
laser cleaning, both positive and negative. The address is:

    <URL:http://lasercleaning.ning.com>

Martin Cooper
Head of Conservation Technologies
National Museums Liverpool


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                  Conservation DistList Instance 22:51
                 Distributed: Wednesday, March 11, 2009
                       Message Id: cdl-22-51-008
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