Latex paint on exhibition cases

Emily Klayman <eklayman<-a t->sivm< . >si< . >edu> writes

>There has been a policy where I work to let cases painted with latex
>paint dry for two weeks before objects can be placed in them.
>Recently, I have reread articles on the subject that are confusing
>to me. Several imply that latex paint does not offgas, others say
>there is a waiting period of anywhere from several weeks to several
>months.

I recommend to read the paper "Determination of concentrations of
acetic acid emitted from wood coatings in enclosures" by Tetreault,
J. et Stamatopoulou, E. in Studies in Conservation volume 42 (1997)
p.141-156.

Latex or emulsion paints release volatiles as any other liquid
paints. My experiments showed that the greatest decrease in the VOC
emission rate occurs in the early stage of drying and they levelled
off around 20-30 days. However, even a low emission rate may still
be considered potentially harmful to objects.

If we had a discussion about just latex paint, lets say, on a non
emissive substrate such as a drywall [text missing]. For an
air-tight enclosure with a mixed collection, Probably latex paints
in general cannot offer a proper protection to the collection.

When latex paint is required inside an air-tight enclosure, I
suggest a drying period of 30 days (a delay that probably very few
of us can respect!). For leaky enclosure, 2 weeks; and for
ventilated enclosure or open environment such as an exhibit room, 4
days is enough.

CCI will publish a technical bulletin somewhere in 1998 on
commercial coatings for museum purposes. It will deal with paints
for wood, metal and cementitious substrates in different situations
(enclosures, walls, floor).

Jean Tetreault, CCI

                                  ***
                  Conservation DistList Instance 11:27
               Distributed: Wednesday, September 17, 1997
                       Message Id: cdl-11-27-001
                                  ***