The Center for Scientific Studies in the Arts' Science for Art Fall 2018 Speaker Series welcomes Dr. Łukasz Bratasz on November 2nd for his talk "Understanding paintings' (lack-of) vulnerability to environmental variations."

Join us for a lecture and discussion on the process of cracks saturation fundamental to understanding why panel paintings survived remarkably well in uncontrolled environments of historic houses or places of worship for several centuries. The process of cracks formation was analyzed using computer simulation supported by experimental determination of relevant mechanical properties.

Dr. Łukasz Bratasz is Professor at the Haber Institute of Polish Academy of Sciences.

Talk Details:

Friday, November 2nd, 12-1pm
Cook Hall – Cook 2058
2220 Campus Drive
Evanston, IL, 60208

Full Abstract:

"Understanding paintings' (lack-of) vulnerability to environmental variations"

Dr. Łukasz Bratasz, Haber Institute of Polish Academy of Sciences

Relative humidity (RH) variations were recognized as one of the main causes of the mechanical damage to works of art, especially panel paintings. Implementation of active climate control based on stringent environmental specifications has been a frequent preventive conservation measure adopted in museums imposing significant financial, operational and environmental cost. Currently accepted environmental specifications were designed using results from mechanical tests on new or artificially aged materials subjected to RH variations, and crack initiation in undamaged material served as a selection criterion. However, mechanism of mechanical damage development in historic works of art with their accumulated damages and long environmental history can be only partially understood by studying undamaged mockups. This is especially true for panel paintings considered as one of the most vulnerable to humidity variation class of objects. Panel paintings frequently exhibit pronounced craquelure pattern generated by drying of the paint, mechanical impacts and environmental variations.

The presented paper analyzes the process of cracks saturation fundamental to understanding why panel paintings survived remarkably well in uncontrolled environments of historic houses or places of worship for several centuries. The process of cracks formation was analyzed using computer simulation supported by experimental determination of relevant mechanical properties. A double layer elastic model with fractured overlying paint layer containing both cracks and delaminations was subjected to uniaxial tension. Critical separation between cracks below which any new edge crack cannot grow was determined and compared with patterns observed in real paintings. Evaluation of propagation of micro-cracks imbedded in paint layer was analyzed based on estimation of normalized energy released rate.

In addition, generation and propagation of horizontal interlaminar cracks was studied to understand the effect of their propagation on saturation distance of vertical cracks as well as load carrying ability of paint layer. The contributing modes of crack propagation and their significance are also discussed for these two types of cracks. The impact of crack saturation on allowable range of relative humidity variation is also discussed.

For more information, please visit the Center for Scientific Studies in the Arts' website.