{'fraction_non_alphanumeric': 0.018055555555555554, 'fraction_numerical': 0.005555555555555556, 'mean_word_length': 5.054621848739496, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Colour Change in Sample - Reconstructions of Vincent van Gogh's Grounds due to Wax-Resin Lining

Abstract This study examined the visual impact (colour change) of wax-resin lining on sample reconstructions of Vincent van Gog's grounds, made as part of the Historically Accurate Oil Painting Reconstruction Techniques (HART) Project. The lining method followed that used by J.C. Traas for lining paintings by Van Gogh between 1926 and 1933. Visual changes in the ground samples after living were noted and colour change was measured using a reflectance spectrophotometer. The binding medium of the ground was found to be the most significant factor, with the greatest darkening occurring in samples bound in glue, followed by emulsion and oil. The presence and the method of application of size used in the preparation of the ground samples and the inorganic composition also influenced darkening and colour change as a result of lining. Grounds on unsized canvas darkened the most, while a layer of gelled size reduced impregnation with the lining adhesive and concomitant darkening. Chalk-containing grounds darkened more than grounds containing barium sulphate or lead white. Comparisons between the reconstruction samples and wax-resin lined paintings by Van Gogh highlighted difficulties in attributing the darkening of the ground in the paintings to the lining or to other factors, such as staining by original oil binder in the paint.