Specificazione del colore di provini di terracotta calatina

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Abstract

[automatically translated] The classification of the excavated pottery provides for the allocation of a tint to each shard found, but the regular use of a system for color specification is today an open question. Archaeologists prefer the Munsell Soil Color Chart but the classification derived, as well as the subjectivity inherent in such a system, suffers from an additional variable linked to the difficult realization on the excavation sites of the controlled lighting conditions for the comparison between the boards and shards. The ceramic color is also highly dependent on the cooking conditions so that even products made with the same raw materials can have high color variations. It is in this context that fits the research project in which the work was carried out here presented born in Caltagirone, one of the main producing centers in Sicily since ancient times. The project stems from the craftsmen, who hand down this tradition from father to son, to identify the relationship between the processes of cooking and color of their articles; this project involves the Art Institute for Ceramics in Caltagirone and PH3DRA laboratory of the Department of Physics and Astronomy, University of Catania. On this occasion we present the results for the specification of the color of the two types of dough that characterize calatina production used by potters to obtain, respectively, ceramics commonly used and most prized artifacts. The preparation of the dough, in which he played a key role experience of craftsmen, was made using clays from the main quarries of historical importance, now disused, identified thanks to a major historical and archival research. the set of representative specimens were thus obtained the two types of production, which were then subjected to cooking by varying the maximum temperature between 400 ° C and 1200 ° C. These limits are designed to simulate, as required by potters, even the "cooking mistakes" usual ateliers and which represent the scraps. The crockery made were subjected to color measurements with the spectrophotometric method by recording, for each of the samples, the trend of the spectral reflectance factor and colorimetric backhoe in CIELAB space. Color variations between samples subjected to different temperature values were assessed in the light as a reference sample before cooking, called "raw." This objective has been reached, for both sets, through the comparison of the performance of spectral reflection factors and the representation of the chromatic coordinates L * C * h as a function of temperature.
Original languageItalian
Number of pages8
Publication statusPublished - 2011

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