Lokalt glättade ytor på matt oljemåleri - tre metoder som kan regenerera ytstrukturen

Abstract

The thesis aims to investigate the suitability of three methods for regenerating a porous, matte surface structure in glossy abraded areas, these being scalpel, acetone and 3T (a combination of triethanolamine, Triton X-100 and triammonium citrate). The study focused on abrasions on young, matte oil paint and alkyd oil paint where no visible loss had occurred. Tests were conducted on two test plates, one comprising a 12 year-old oil painting containing white lead and caput mortuum on a gesso primer, the other comprising alkyd oil paintings of differing thicknesses and textures on similarly absorbent grounds. Ocular and stereomicroscopic inspections of the test surfaces were undertaken, whereby the efficacy of the respective methods was measured in terms of reduced gloss. Further analysis using a scanning electron microscope yielded topographical images indicating that the structure and grain of the surfaces resembled those of the intact paint after contact with acetone and 3T. Unlike acetone and 3T, the scalpel produced a matte effect by means of the introduction of small troughs, increasing the unevenness of the surface and implying a greater diffusion of reflected light. Acetone created the most palpable matte effect, likely thanks to the substance's capacity to leach the oil paint film. Acetone also afforded the opportunity to work with substantial precision and speed. 3T produced a matte effect on both alkyd and traditional oil paint, although application time varied due to the disparity in the paints' reactivity. Caput mortuum reacted first, followed by white lead. Alkyd oil paint required the longest contact duration before a matte effect on the surface was achieved. When utilising 3T, residue remained on the surface which required removal by rolling a water-soaked cotton swab over the affected area. In doing so, traces of 3T spread beyond the marked area, producing a matte effect on a larger area than intended. The textural variations in the alkyd oil paint did not appear to be of significance for the effectiveness of the respective methods. A summary of the thesis is provided in English.