雷愛文　童華　萬(wàn)曉霞

摘 要：中國(guó)文化遺產(chǎn)蘊(yùn)含著中華民族特有的精神價(jià)值、思維方式、想象力，體現(xiàn)著中華民族的生命力和創(chuàng)造力，是各民族智慧的結(jié)晶，也是全人類文明的瑰寶。敦煌莫高窟是著名的世界文化遺產(chǎn)，莫高窟壁畫以其精美的圖像、深刻的歷史價(jià)值受到廣泛的重視。然而，敦煌壁畫由于受到當(dāng)?shù)氐淖匀画h(huán)境和人文環(huán)境的影響，以及壁畫制作材料和制作工藝等內(nèi)在因素的作用，產(chǎn)生了多種病害，如壁畫起甲、空鼓、大面積脫落、煙熏、霉變、酥堿以及變色等。礦物顏料變色機(jī)理的研究主要有以下幾個(gè)困難：（1）目前已有的實(shí)驗(yàn)儀器僅僅只能單一檢測(cè)某一種元素的變化，而不能同時(shí)實(shí)現(xiàn)多種元素及多種化合物變化的檢測(cè)；（2）現(xiàn)實(shí)生活中，礦物顏料變色是一個(gè)較為漫長(zhǎng)的過(guò)程，不適合實(shí)驗(yàn)室研究，短期內(nèi)無(wú)法獲得較為真實(shí)確切的成果；（3）礦物顏料變色是一個(gè)多因素影響的過(guò)程，這為該研究工作帶來(lái)巨大的困難?；谝陨涎芯勘尘芭c困難，該研究對(duì)礦物顏料變色機(jī)理的研究提出了一條全新的研究思路。首先，利用X-射線同步輻射技術(shù)研究敦煌壁畫顏料顏色變化的機(jī)理。X-射線同步輻射技術(shù)具有通量大、亮度高、頻譜寬、連續(xù)可調(diào)等特點(diǎn)，在研究礦物顏料表面化學(xué)組分、表面結(jié)構(gòu)、表面原子態(tài)和電子態(tài)具有其他儀器無(wú)法具備的優(yōu)勢(shì)。并且能夠在不破壞樣品的情況下分別選擇性地研究各種組分的變化；其次，實(shí)現(xiàn)礦物顏料的加速老化實(shí)驗(yàn)，極大縮短了礦物顏料顏色變化時(shí)間，能夠在短期內(nèi)對(duì)顏料變化過(guò)程進(jìn)行全面的研究，并且能夠控制多因素對(duì)顏色變化的影響。基于光譜的文化遺產(chǎn)顏色再現(xiàn)的方法可以降低傳統(tǒng)顏色再現(xiàn)方法所固有的同色異譜問(wèn)題，實(shí)現(xiàn)設(shè)備無(wú)關(guān)、場(chǎng)景無(wú)關(guān)、觀察者無(wú)關(guān)的無(wú)條件顏色再現(xiàn)。該報(bào)告研究了高光譜分辨率和高空間分辨率的文物顏色環(huán)境無(wú)關(guān)數(shù)據(jù)獲取方法，建立了敦煌顏料光譜數(shù)據(jù)集，基本實(shí)現(xiàn)了基于光譜的噴墨顏色真實(shí)再現(xiàn)。通過(guò)色域判斷的方法，建立了5類光譜分色子模型，通過(guò)光譜色域映射的方法實(shí)現(xiàn)了光譜真實(shí)色彩再現(xiàn)。以敦煌典型顏料樣本集為例，進(jìn)行了精度驗(yàn)證。光譜誤差以均方根誤差RMS表示，色度誤差以CIEDE2000色差形式表示。實(shí)驗(yàn)結(jié)果為：光譜誤差RMS=0.0326；色度誤差DE2000（D50/2）=3.541；DE2000（A/2）=3.268；DE2000（F1/2）=3.497；該結(jié)果表明，該文提出的方法對(duì)于各類樣本集皆具有理想的色彩再現(xiàn)精度。

關(guān)鍵詞：文化遺產(chǎn) 敦煌壁畫 物質(zhì)基礎(chǔ) X-射線同步輻射 老化實(shí)驗(yàn) 光譜預(yù)測(cè) 顏色再現(xiàn) 敦煌顏料 同色異譜

噴墨再現(xiàn)

Abstract：The cultural heritage of the Chinese nation contains the unique spiritual values， ways of thinking， imagination， embodies the vitality and creativity of the Chinese nation， and is not only the crystallization of the wisdom of the whole nation， but also a treasure of human civilization. Dunhuang Mogao Grottoes is the famous world cultural heritage. The Mogao Grottoes murals gain prominence owing to the profound historical value and exquisite image. However， due to influence of the local natural and humanities environment and the painting materials and fabrication process， the Dunhuang murals are faced with the problems， such as flake， Konggu， chip， smoked， mildew， efflorescence and discoloration， etc. The study on the mechanism of mineral pigment discoloration mainly has the following several problems：（1） the currently available instrument can only detect the change of just one element a time， and can not do it simultaneously；（2） the color change of mineral pigment is a long process in real life， which is not suitable for experimental research in short term；（3） the color change of mineral pigment can be affected by multiple factors. All the above reasons make this research difficult. Based on the above research background and difficulties， we put forward a novel method to the study of the mechanism of mineral pigment discoloration. First of all， the mechanism of the color change of Dunhuang mural pigment can be studied by using the X - ray synchrotron radiation. X - ray synchrotron radiation technique has the merits of high flux， high brightness， wide spectrum， continuously adjusted， in the study of mineral pigment surfaces chemical composition， surface structure， surface atomic and electronic states， which other instruments do not have. X - ray synchrotron radiation has the ability to study different components selectively without destroying samples. Secondly， accelerated aging test of mineral pigment can greatly shorten the time needed for the color change of mineral pigment， so a comprehensive study on pigment change process and multiple factors on the color change can be done in a short time. Spectral-based color reproduction of culture heritage can reduce the metamerism problem in the tranditional color reproduction workflow and fulfil the devices-independent， scenes-independent and observers-independent color reproduction. It ultimately achieves the goal of high precision color reproduction of cultural heritage.

Key Words：Cultural heritage； Dunhuang murals； Material foundation； X-ray synchrotron radiation； Aging test； Spectral prediction； Color representation； Pigments used in Dunhuang； Ink jet printing； Metamerism

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