In the present work we determined the chromatic coordinates (L*, a*, b*) for three building stones used in the heritage city of Ávila, Spain (World Granite Heritage City, 1988). The stones came from quarries and were subjected to 90 cycles of three types of accelerated ageing processes: (a) freezing/thawing together with cooling/heating (T1); (b) salt crystallisation (T2); and (c) freezing/thawing together with cooling/heating + salt crystallisation (T3). A three-way mixed MANOVA (multivariate analysis of variance) was applied to the data obtained. Significant variations in the three chromatic coordinates (L*, a*, b*) were observed between the three types of accelerated artificial ageing processes compared to the data obtained from the quarry samples, with a tendency towards darkness (↓L*), redness (↑a*) and much less intensity towards yellowing (↑b*).

The authors are grateful for financial support for thiswork from the Ministry of Science, Innovation and Uni-versities (PGC2018-098151-B-I00), Proyect“CLU-2019-05–IRNASA/CSIC Unit of Excellence”, funded by the Junta de Castilla y León and co-financed by the European Union (ERDF “Europe drives our growth”) and supportof the publication fee by the CSIC Open Access Publica-tion Support Initiative through its Unit of InformationResources for Research (URICI)

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Peer reviewed