* Evaluation of Different Vermilion Treatment Methods Presented in Art Treatises of the 16th – 17th Centuries

   Preparing basic materials for illustrating the manuscripts, i.e., paper, paint and brushes, have important role for painters. Each of these parameters have direct effects on the appearance and durability of the final product. Vermillion is a red inorganic pigment with the chemical composition HgS. Regarding its widespread usage, high quality and great durability, the vermilion pigment has been used as a prominent and noticeable color in Iranian paintings during the time and especially in the period of book decoration and illustration of manuscripts by many artists and painters. From historical point of view, production and preparation methods of vermillion were mentioned in the art treatises, mainly during the 16^th – 17^th centuries. Although in many researches vermillion was characterized as a useful color in illustrated manuscripts, but less attention has been paid to historical references and methods of preparing this color. In this paper, different tonality of reproduced vermillion based on the recipes presented in art treatises belong to the 16^th – 17^th centuries were investigated through colorimetric analysis. Descriptive- analytic and laboratory methods were applied in this research. Five manuscripts from the mentioned era including Golestan-e Honar, Ghanoun al-Sovar, Medad al-Khotout, Heliyyat al-Kottab and Adaab al-Khat were firstly investigated based on the library resources. According to the art treatises, the vermilion pigment can produce from the combination of pure mercury and sulfur and/or obtain from cinnabar as HgS natural mineral. In this research cinnabar was used. Next, the vermilion specimens were reproduced based on laboratory methods according to presented recipes in in five mentioned art treatises. It is noticeable that the main difference between proposed methods was based on the application of different organic acids for washing of the color powder. Regarding to these art treatise, two organic acids (lemon juice and sour pomegranate juice) as well as the citric acid were used for preparing vermilion samples in acid washing step. In order to prevent the side effects of different parameters on the test results, all processes and materials were the same, except the organic acid type. For comparing reproduced vermilion colors, they were applied on Watman sizing papers which were sized by starch. For analyzing and comparing of these different tints, the standard system near to human observation was needed. Regarding to this aim, samples were quantitatively compared based on their measured reflectance spectra by spectrophotometer i1 and calculating their colorimetric characteristics in various color spaces; CIEXYZ, CIELAB, and CIELCH, by using the MATLAB software.