A new method for consolidating wall paintings based on dispersions of limein alcohol

Dispersions of calcium hydroxide, Ca(OH)(2), in short-chain alipathic alcoh ols were studied with the aim of establishing a new pre-consolidation and c onsolidation methodology for wall paintings. The choice of lime (a paste co mprising calcium hydroxide plus water) as the consolidant was suggested by physicochemical compatibility criteria, as lime is the original binder in t he wall paintings treated. Many problems are encountered when trying to app ly calcium hydroxide to wall paintings. Saturated solutions are too weak to act in water are too unstable to be applied to unprotected painting surfac es. The use of Ca(OH)(2) dispersions in propan-1-ol is proposed, these disp ersions were characterized, and their kinetic stability investigated, by ul tra-violet/visible spectrophotometry. The alcohol dispersions were found to be much more stable than suspensions in water. The second part of the stud y evaluated the consolidating power of alcohol dispersions on specimens tha t simulate different degrees of decohesion. These were examined using X-ray diffractometry and Fourier transform infrared spectroscopy. Their surface properties were characterized by studying capillary rise, water metric resi stance and the 'Scotch Tape test'. All the results indicated that the lime/ alcohol dispersions produced excellent consolidation. Finally, the paper re ports the positive results of tests using the lime/alcohol dispersion on wa ll paintings by Andrea da Firenze in the Cappellone degli Spagnoli, Chiostr o Verde of Santa Maria Novella, Florence