Restoration at Balzan parish church

I refer to David Borg’s letter (The Sunday Times, March 27).

This is a quote from ‘Balzan Parish Church Environmental Monitoring Report’ (December 2006), commissioned by the Balzan Heritage Commission and compiled by Ingrid Ross:

“From this study it can be determined that the air-conditioning unit used during church services is not caus-ing rapid and extensive fluctua-tions in relative humidity and temperature. As a consequence, the air-conditioning units cannot be implicated in the damage sustained by the paintings.”

Pierre Bugeja, senior conservator-restorer of paintings of Prev Arti, who carried out the restoration of the Calì paintings in the Balzan church choir and is at present conducting tests on the Cremona paintings in the cupola of the crucifix, gave me this report:

“After reading through the scientific investigation results in report carried out in 2006 by Ingrid Ross, it is evident that the causes that brought the detachment of the marouflage painting by Emvin Cremona, The Plan of Salvation, are related to the following, either individually or in combination:

“• Salt crystallisation between the stone/previously applied plastic paint and the marouflage adhesive layer due to past water infiltration and after the application of the waterproof membrane from exterior.

“• Soot and dirt over the plastic paint layer not removed prior to the application of the marouflage adhesive.

“• Defect in the adhesive used since it was not the same lead-based type that was commonly used and referred to as bianchette, but a new commercial lead-free type.

“• Structural vibrations from close by workings could also have an effect on the detachment.

“Environmental monitoring confirmed that the installed air-conditioning had no effect on the causes of the detachment of the marouflage painting. Results show­ed the temperature and relative humidity in the cupolas followed the same pattern as that on the external wall and had little effect on these values.

“Fluctuations in temperature and relative humidity are of a direct concern mostly for organic materials made of wood, paper and textiles.

“Due to their hydroscopic nature these materials will expand and contract in relation to changes in the environment, such as temperature and relative humidity, and causing cracks, deformations and detachments among others.”