ارزیابی شیوه‌های عمل‌آوری متفاوت رنگدانه شنگرف در رسالات کتاب‌آرایی قرون 10 و 11 هجری قمری

شنگرف، در نگارگری ایران از دیرباز رنگی پرکاربرد، با کیفیت و ماندگاری بالا بوده است. در مورد روش تهیه و آماده‌سازی این رنگ در رسالات کتاب‌آرایی مطالب مهمی ذکر شده اما از لحاظ عملی این روش‌ها کمتر مورد بحث و بررسی قرار گرفته است. هدف از این پژوهش بررسی کیفیت بصری رنگ حاصل از رنگدانه شنگرف آماده‌سازی شده براساس متون رسالات قرون 10 و 11هجری قمری است، با این پرسش اصلی که براساس معیارهای استاندارد، رنگ های حاصل از روش های متفاوت آماده سازی، چه تفاوت هایی دارند؟ در این پژوهش روش‌های آماده‌سازی این رنگدانه در پنج رساله کتاب‌آرایی شاخص متعلق به قرون مذکور، براساس روش های توصیفی – تحلیلی و آزمایشگاهی با استناد به منابع کتابخانه‌ای و بازتولید عملی رنگدانه، بررسی شده است. نتایج بررسی رسالات کتاب‌آرایی حاکی از تفاوت آماده سازی شنگرف در مرحله اسیدشویی با دو اسید آلی (آب لیمو ترش و آب‌انار ترش) است. جهت بررسی تفاوت ته‌رنگ‌ نمونه های بازتولید شده، نیاز به سیستم شبیه ساز بینایی انسان در شرایط استاندارد بود. این امر با استفاده از آنالیز اسپکتروفتومتر انعکاسی در سیستم استاندارد فضارنگ ciexyz، cielab و cielch انجام شد. نتایج حاصل نشان‌دهنده بازسازی فام قرمز با ته‌رنگ‌های متفاوت شامل تنالیته قرمز شفاف، ته رنگ نارنجی و ته رنگ صورتی برای نمونه‌های مختلف شنگرف‌ تولید شده با مواد اسیدشویی متفاوت است.

* 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 16th – 17th 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vermillion was characterized as a useful color in illustrated manuscripts, but less attention has been paid to historical references and methods of preparing this color.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 16th – 17th centuries were investigated through colorimetric analysis. Descriptive analytic and laboratory methods were applied in this research. Five manuscripts from the mentioned era including Golestane Honar, Ghanoun alSovar, Medad alKhotout, Heliyyat alKottab and Adaab alKhat 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.