將掛軸或手卷攤平舒展後，其邊緣會呈兩個半月形向上翻捲，稱之為「起瓦（Qi-Wa）」。它除了有礙美觀外，還會造成卷軸畫產生不可逆的變形，進而成為裂痕，讓顏料脫落等狀況，自從中國發展裝裱工藝一千六百多年以來一直困擾著藝術家們。但在過去裝裱師父及研究人員探討此問題時，總是將其歸因於氣候問題、保存條件、裝裱工序及制糊的方法等，而在本研究我們強調是由紙張塑性所產生的「內在曲率（spontaneous extrinsic curvature）」才是造成起瓦的主因。在實驗上我們發現起瓦高度會和紙張的長度、寬度、厚度以及曲率呈簡單的冪次關係，這亦可從分子動力學模擬（Molecular Dynamics (MD) simulation）和理論推導得到同樣的現象。由理論的暗示，我們歸納出幾種可以改善起瓦的方法，在真實的裝裱紙和分子動力學模擬皆證明其可行。而此類的捲曲問題不只存在於中國的卷軸畫中，在工業上也會遇到類似的問題，例如近年來熱門的可撓式面板、電子紙以及印刷太陽能板，同樣會因為捲曲而起瓦變形。

"Qi-Wa" is the phenomenon that occurs in handscrolls and hanging scrolls; once we spread the roll paper, it is easy to notice the up curl on the sides of paper. In addition to aesthetic aspect, it results in irreversible effects such as tears and pigment loss, which has troubled Chinese artisans for more than 1600 years. Previous works suggest that Qi-Wa comes from the climate effect, conservation conditions, and/or mounting procedures. However, we find that the main cause of Qi-Wa is the spontaneous extrinsic curvature incurred from the storage. According to experiments, we find that the height of Qi-Wa obeys simple power laws with the scroll's length, width, thickness and curvature. This result is supported by Molecular Dynamics (MD) simulation and theoretic derivations. Based on the theory, we propose several methods to reduce Qi-Wa. These methods have been tested by use of real mounted paper and simulations, and are proved workable. Our study can be applied to modern technologies, since similar warps occurs not only in Chinese scrolls but also in industry productions of flexible display, electronic paper, and paper solar cell circuit.

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