Article: Microclimatic variations for painted wood (2010)

Title: Allowable microclimatic variations for painted wood: direct tracing of damage development
Author: Roman Kozłowski, Łukasz Bratasz, Łukasz Lasyk, Michał Łukomski
Reference: Postprints of Symposium ‘Facing the Challenges of Panel Paintings Conservation: Trends, Treatments and Training’, eds. A.S. Chui, A. Phoenix, Getty Conservation Institute, Los Angeles, to be published on line in mid- 2010.
Link: http://heritagescience.pl/... (pdf, 1.15 Mb)

Abstract:

Uncontrolled variations of ambient temperature and relative humidity (RH) are the principal hazard to the preservation of panel paintings which are frequently exposed to real-world dynamically changing environments. Materials that constitute panel paintings, such as hide glues, gesso, paints and varnishes respond to these variations by gaining moisture when humidity is high and losing moisture when the surrounding air is dry. The materials respond dimensionally to the sorption and desorption of moisture; they shrink as they lose moisture and swell when they gain moisture. A notable effect is that panel materials each respond differently to the loss and gain of moisture, which induces high stress in the different layers of painting leading to damage if the strength of a given material is exceeded.