بررسي ساختار رنگ دانه هاي به كار رفته در گچبري هاي به دست آمده از محوطه قلعه يزدگرد

Painted Parthian Stuccoes from Qal‘eh-i Yazdigird

دوره ي اشكاني سرآغاز استفاده از گچبري در تزيينات معماري ايران بود و از قرن دوم م. به بعد شاهد به كارگيري رنگ هاي متنوعي برروي زمينه ي سفيد گچبري ها هستيم كه به آن ها جلوه ي زيبايي بخشيده اند. به نظر مي رسد كه هدف از رنگ آميزي اين آثار كه زينت بخش بناهاي مهم دوره ي اشكاني بوده اند، علاوه بر جنبه ي بصري، تاكيد بر انتقال پيام سازندگان و بانيان آثار نيز باشد. يكي از مهم ترين محوطه هايي كه گچبري هاي ارزشمندي از آن به دست آمده، محوطه ي تاريخي قلعه يزدگرد است. اين گچبري ها شامل نقوش: انساني، حيواني، هندسي، گياهي، تركيبي و عناصر معمارانه است. قطعات بسياري از گچبري هاي فوق، رنگ آميزي شده اند. اين قطعات، داراي يك يا چندرنگ هستند، اما تاكنون برروي رنگ هاي به كار رفته در آن ها پژوهشي صورت نگرفته است؛ اين درحالي است كه گچبري هاي قلعه يزدگرد از مهم ترين محوطه هاي مهم دوره ي اشكاني است كه قطعات قابل توجهي گچبري رنگين از آن كشف شده است. هدف از اين تحقيق، پاسخ گويي به اين سوالات بوده است: 1. رنگ هاي به كار رفته در گچبري هاي قلعه يزدگرد كدامند و آيا رنگ در صحنه و نقش خاصي به كار رفته است؟ 2. براي رنگ آميزي گچبري هاي اين محوطه از چه رنگ دانه هايي استفاده شده است؟ اين تحقيق با استفاده از مطالعات موزه اي و كتابخانه اي انجام شده است؛ هم چنين گچبري هاي رنگين اين محوطه، براي نخستين بار مورد آزمايش قرار گرفتند. براي بررسي و آناليز رنگ دانه ها از روش هاي پراش پرتو ايكس (XRD)، آزمايش پتروگرافي و طيف سنجي زير قرمز تبديل فوريه (FTIR) استفاده گرديد. طبق نتايج به دست آمده، در گچبري هاي قلعه يزدگرد از رنگ دانه ي آبي مصري براي رنگ آبي، از رنگ دانه ي سبز خاكي (سبز سيلو) براي رنگ سبز و براي رنگ هاي قرمز، صورتي و زرد از رنگ دانه ي اُخرا استفاده شده است. به نظر مي رسد كه در قلعه يزدگرد براي رنگ آميزي نقوش از رنگ دانه هاي كاني استفاده شده و از رنگ دانه هاي آلي براي توليد رنگ در اين مجموعه استفاده نشده است.

The use of stucco decoration on buildings has become popular in Iran from the Parthian period but from the second century onwards stucco decorations were painted in bright colors. An im-portant group of the Parthians Painted Stuccoes excavated in the 1965-79 and 2008 in Qal ‘eh-i Yazdigird. Qal’eh-i Yazdigird is a Parthian Palace Stronghold in the Zagros range of mountains in western Iran. During the excavations carried out in Gach Gumbad and Hushtareh areas a total of 389 stucco pieces were found and have been repaired. In comparison to the simultaneous Parthian areas such as Uruk، Seleucia، Kuh-i Khwaje and Assure، the motifs of the stuccoes of Qal’eh-I Yazdigird witnessed the greater diversity and amount of the motifs leading to the fact that the stuccoes here have being used to decorate a larger sections of the buildings in these complex. The stuccoes are used to decorate walls، part of columns، capitals، niches and cornices of the buildings. The stuccoes of the Qal’eh-I Yazdigird can be divided into 6 major groups ac-cording to the type of decoration، including human، animal، floral، geometric، architectural and compound elements and motifs. Much of the stucco decorations were vividly painted. Some of the fragments are Polychrome. In Qal’eh-I Yazdigird، painted stuccoes in comparison with the other simultaneous areas were widely used so that out of 163 pieces of stuccoes from there، 69 pieces (42.3 percent) were painted. In fact، painting has been the latest stage in the creation of stucco decoration process. In Qal’eh-I Yazdigird site، to the best representation of the motifs، the surface of stuccoes was firstly painted by a bright color while the motifs themselves were generally painted by the paints darker than the background one. These colors consist of green، deep blues، pink، deep reds، orange، brown، purple and yellow. In some cases، motifs were deco-rated by a particular paint (e.g. blue، red، green) which have mainly been used to portrait hunt-ing scenes، a woman capital with two dolphins in hand and griffins. Some parts were also fre-quently painted by two or three paints such as pink and green crenellations as well as making more contrast between paints and the background plasters which would enhance the magnifi-cence and beauty of the stucco decorations. For the stuccoes of Qal’eh-I Yazdigird، it cannot be said that the coloring is confined to a particular motif or scene، since the study of Qal’eh-i Yazdigird stuccos is still incomplete and the impact of environmental factors in the modifica-tion of the stucco colors have not yet been properly identified. In this research because of the importance of stuccoes of Qal’eh-I Yazdigird we tried to sample the stuccoes available in the National Museum of Iran to identify the kinds of pigments used as well as to understand the technology by which the colorful stuccoes of the Parthians were appeared. These were analyzed for the first time within in 2013 in Iran by the authors present. The pigments red ochre and yel-low ochre (identified by the presence of the main chromophores hematite and goethite)، Egyp-tian blue and green earth (terre-verte glauconite) were found on decorated surfaces. FTIR، X-ray diffraction (XRD) and Petrography methods have been used to study the characterize pig-ments used in the stucco decoration. In fact، only inorganic pigments are used for painting stuc-coes and botanic pigments have not been identified. The existence of the Egyptian blue pigment which is a handmade material proved to have been used for the first time during the Parthian period but still we do not know whether it was imported or has been made locally. It is a chal-lenge should be clarified by the further researches.