Rosy Tint For a Faded Renoir Lady
雷諾瓦仕女畫 紅潤重現
By Kenneth Chang

Conservators at the Art Institute of Chicago wanted to solve the mystery of the missing pigment.
芝加哥藝術學院的文物修復師很想解開失落顏料的謎團。

They were looking at “Madame Léon Clapisson,” an 1883 portrait by the French Impressionist Pierre-Auguste Renoir, which had just been removed from its frame for study. The part that had been hidden behind the frame was markedly more vivid.
他們檢視19世紀法國著名印象派畫家雷諾瓦的1883年作品「克拉皮森夫人」。管理人員最近才將它自畫框中取出，以便深入研究。藏在畫框後面的畫作部位色彩鮮豔許多。

“It’s been protected from light, so we were able to really appreciate the original color in this unfaded area,” said Francesca Casadio, the museum’s senior conservation scientist. “It’s really quite striking. It’s a very scarlet-purple kind of paint.”
芝加哥藝術學院資深保存修復科學家法蘭西絲卡‧卡沙迪歐說：「這個部位與光隔絕，使我們得以欣賞到此一未褪色部位的原始顏色。實在非常醒目。它是一種非常猩紅紫色的顏料。」

Although the bright edges were observed about 15 years ago, the museum did not have the scientific facilities then to investigate. But four years ago, a project to create a digital catalog of the museum’s Renoir holdings provided an opportunity to run a battery of scientific tests.
雖然明亮的邊緣大約15年前就發現了，芝加哥藝術學院當時卻並無深入研究所需的科學設施。然而四年前，該學院開始執行為館藏雷諾瓦作品製作數位化目錄的計畫，使保存人員有機會進行一系列的科學檢驗。

Kelly Keegan, the conservator working on the project, said a look under the microscope revealed that the color shift was not a revision by Renoir himself or caused by imprudent cleaning. “It’s very clear it’s original paint,” she said. “You can see there are particles on the surface that are sort of translucent now.”
執行這項計畫的修復師凱莉‧基根表示，她與同事利用顯微鏡檢查後發現，色彩不是因為雷諾瓦親自修改或不小心的清理而出現變化。她說：「它顯然是最初的顏色。你可以看到，表面上的一些微粒如今已經變得有點半透明。」

The unfaded edges did not have the translucent particles, which evidently contained pigment molecules that had fallen apart, losing their color.
未褪色的邊緣不含半透明微粒。半透明微粒所含的顏料分子顯然已經分解，最後失去光采。

Conservators around the world regularly bathe their paintings with light of different wavelengths – infrared, ultraviolet, X-rays – to see what might be hidden. But those techniques cannot identify organic pigments, extracted from plants and insects, which were popular with the Impressionists. For that, Dr. Casadio and Federica Pozzi, both conservation scientists who were trained as chemists, had begun using a laser technique called surface-enhanced Raman spectroscopy.
全球各地藝術館的修復師經常以各種不同波長的光檢查館方收藏的畫作，包括紅外線、紫外線與X光，以查明其中隱藏的東西。然而這些技術無法辨別萃取自植物與昆蟲的有機顏料。印象派畫家都喜歡用這種顏料。有鑑於此，卡沙迪歐博士與同為化學家出身的另一修復師菲蒂莉卡‧波希開始使用名為「表面增強拉曼光譜學」的雷射技術。

When the laser hits a material, photons bounce off it, some of them inducing vibrations in the molecules and shifting the photons’ wavelengths. The spectrum of colors in the scattered light is used to identify the molecules. In surface-enhanced Raman spectroscopy, the sample is laid on silver nanoparticles, which amplify the signal.
雷射觸碰一種材質時，光子會彈開，其中一部分誘使分子出現振動，同時改變光子的波長。分散光線中的顏色光譜用於辨別分子。使用這種技術時，把樣本置於會放大訊號的銀色奈米粒子上。

Using a red speck scraped from the painting’s edge, the scientists identified the pigment: carmine lake, made from cochineal insects that live on cactuses in Mexico and South America. (Ground-up cochineal is used today as a natural coloring when longevity is not required. Starbucks used to add it to some of its drinks, but stopped in 2012 after complaints from vegetarians.)
她們從畫作的邊緣取下一個紅色小片，果然看到顏料：胭脂紅顏料。這種顏料以存活於墨西哥與南美洲仙人掌的胭脂蟲製成（如果不考慮存放期限，磨成粉狀的胭脂紅如今充當天然著色劑。星巴克連鎖咖啡曾經把胭脂紅加入部分飲料產品中，素食人士抗議後，2012年起不再添加）。

The striking red color had evidently caught Renoir’s eye.
這種醒目的紅色顯然曾經引起雷諾瓦的注意。

But it does not last.
然而它無法持久。

Even paint catalogs of the era noted that the color wasn’t stable when exposed to light. “I think the artists didn’t realize the colors could fade away entirely,” Dr. Casadio said.
即使當時的繪畫顏料目錄也記載，一旦與光接觸，色彩就會不穩定。卡沙迪歐說：「我認為，當時的畫家不知道顏色可能會完全消失。」

There are no thoughts of trying to restore the portrait to its original hues, but with computer software Ms. Keegan was able to create a digital version of how it might have looked in 1883.
芝加哥藝術學院不打算讓「克拉皮森夫人」恢復原有的色調。不過基根利用電腦軟體製作數位版，重現它1883年的可能原貌。

The cool background of grays, blues and greens was instead a hotter swath of red and purple – “in some ways, more daring, more adventurous,” said Gloria Groom, the museum’s senior curator. “It’s so weird. You think you know an artist, and then science tells something different about him and you’re like, ‘Oh, well, that doesn’t fit my idea of what this artist is.’ ”
灰、藍、綠的冷色調背景其實是一片比較溫熱的紅色與紫色。芝加哥藝術學院的資深策展人葛洛莉亞‧葛倫姆說：「以某些方面來說，更大膽，更具有冒險性。這是如此不可思議。你自認很瞭解一名畫家，科學接著揭露有關畫家的不同事實。這時候，你會說，『噢，這不符合我對這位畫家的理解。』」

“Madame Léon Clapisson” is not the only painting to change color over the years. Conservators recently found a deeper, more intense red on the sleeve of one of the children in Paul Gauguin’s “Polynesian Woman With Children” – again, part of the canvas that had been protected by the frame.
「克拉皮森夫人」並不是多年後色彩出現變化的唯一畫作。管理員最近在法國後印象派畫家高更畫作「與孩子們在一起的玻里尼西亞婦女」當中，一名孩子衣服的袖子上發現更深更強烈的紅色。它又是畫框保護下的結果。

Dr. Pozzi said, “This could be a very similar fading phenomenon.”
波希說：「這可能是一種非常類似的褪色現象。」

原文參照：
http://www.nytimes.com/2014/04/22/science/renoir-shows-his-true-colors.html

2014-05-06聯合報/G5版/UNITEDDAILYNEWS 陳世欽譯 原文參見紐時週報十版左