吶喊為挪威畫家愛德華·孟克的作品，其呼喊的「怪異」樣貌形象非常鮮明。996Please respect copyright.ＰＥＮＡＮＡgFAb1lXssM
996Please respect copyright.ＰＥＮＡＮＡ55nPo7c5Rt
996Please respect copyright.ＰＥＮＡＮＡz6Xmk4PYv4
他本人在1893至1916年畫出多個版本，而其中一幅展示在孟克美術館（Munch Museum)的版本因多處黃色地方出現變白及脫落跡象關係（圖1的數字標記區域），自2006年起已甚少公開示人。996Please respect copyright.ＰＥＮＡＮＡEwpURuMJhF
996Please respect copyright.ＰＥＮＡＮＡE2swl2uLbt
作品現時正處於光線陰淡、攝氏18度、相對濕度約50%的環境備受保護。996Please respect copyright.ＰＥＮＡＮＡOLWkeevaJl
996Please respect copyright.ＰＥＮＡＮＡCdlDCDqwJQ
996Please respect copyright.ＰＥＮＡＮＡDMRk4Wlrmy
（圖2）為了解箇中顏料變色及脫落的機制，有科學家對吶喊作品作出深入研究，並在近日發表文章講述得出的結果（Ref1)。996Please respect copyright.ＰＥＮＡＮＡFtXvHXEo6T
996Please respect copyright.ＰＥＮＡＮＡ0CBnZnWJ8R
996Please respect copyright.ＰＥＮＡＮＡ0vUNqV8HcK
Cadmium sulfide，為該時期常用作為黃色顏料的化學物。996Please respect copyright.ＰＥＮＡＮＡNRjxh1PVao
996Please respect copyright.ＰＥＮＡＮＡZWLrHMdRxJ
同期的文森·梵谷 (Vincent van Gogh)、詹姆斯・恩索 (James Ensor)和亨利·馬諦斯(Henri Matisse)均有利用這種化學物所製成的顏料，而相關的作品亦有出現黃色顏料變白的現象。996Please respect copyright.ＰＥＮＡＮＡp5EXsMINDV
996Please respect copyright.ＰＥＮＡＮＡ9zwy77QkeX
該時期主要有兩種方式製作Cadmium sulfide，分別為Dry及Wet Method。996Please respect copyright.ＰＥＮＡＮＡxemJV5AH5a
996Please respect copyright.ＰＥＮＡＮＡmrGkPqZTut
Dry Method為以300°C至600°C及零氧氣的方式，加上大量硫元素(Sulphur)調配Cadmium sulfide的方式，得出的成品相對上較為純正。996Please respect copyright.ＰＥＮＡＮＡ4PUVwDw7pu
996Please respect copyright.ＰＥＮＡＮＡTdyXjSQcyI
Wet Method為將不同的化學物混合在一起（如圖中所示），再以沉澱的方式獲取固體Cadmium sulfide。996Please respect copyright.ＰＥＮＡＮＡtIVHwzGOIX
基於當時技術相對上不太先進，最終的產品會含有較多雜質及副產品。996Please respect copyright.ＰＥＮＡＮＡR9egx7RVXN
996Please respect copyright.ＰＥＮＡＮＡT4269kfR4A
（圖3）科學家在文中嘗試挖取微量的吶喊畫碎粒，再利用各種技術檢測畫中的化學物成份。996Please respect copyright.ＰＥＮＡＮＡS52cx0zYMv
996Please respect copyright.ＰＥＮＡＮＡ2HJOkHVmRR
996Please respect copyright.ＰＥＮＡＮＡnlnYmxipXZ
圖3中間的圖片，其紅點代表黃色顏料Cadmium sulfide的存在。996Please respect copyright.ＰＥＮＡＮＡYIOQYQjD0l
996Please respect copyright.ＰＥＮＡＮＡ3ljwF9n5pj
下方的圖片，其三種顏色的出現分別代表Wet Method的副產物。996Please respect copyright.ＰＥＮＡＮＡtGv2aBtWxJ
996Please respect copyright.ＰＥＮＡＮＡ5PpA8vaY4i
紅點:Cd(OH)Cl996Please respect copyright.ＰＥＮＡＮＡli2IVoVqCb
綠點:CdSO4996Please respect copyright.ＰＥＮＡＮＡLMHD45Rzkg
藍點:CdCO3996Please respect copyright.ＰＥＮＡＮＡhX6WV5Gttm
996Please respect copyright.ＰＥＮＡＮＡbqoB1Dm4Ty
這三種副產物，在長久而來的知識中已被確認是顏料變色及脫落的兇手，與吶喊作品所出現的現象不謀而合。996Please respect copyright.ＰＥＮＡＮＡo63aiYQSVl
996Please respect copyright.ＰＥＮＡＮＡra2aWxOQgA
（圖4）為進一步了解顏料變色的現象，他們找來了吶喊畫同期帶有黃色顏料的作品(他們已7914數字命名樣本)。996Please respect copyright.ＰＥＮＡＮＡ5Rl3IYOj6t
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拿取畫中碎片後，（圖4左方）他們同樣發現裡頭含有Wet Method的副產物（綠點）。996Please respect copyright.ＰＥＮＡＮＡ8cXC1XA17s
996Please respect copyright.ＰＥＮＡＮＡtLbJU8EGk6
為了解環境因素對於顏料變色的影響，他們對另一塊畫碎用上90 日相對濕度≥ 95%，攝氏為40°C，無光環境來模仿歲月的摧殘。996Please respect copyright.ＰＥＮＡＮＡMTgzGPRKLo
996Please respect copyright.ＰＥＮＡＮＡ3pzhWS7YGw
他們發現得到Wet Method的副產物Cd(OH)Cl（綠點）數量大增且集中在一起，其目測得到黃色顏料變白的現象發生。996Please respect copyright.ＰＥＮＡＮＡciFrOyrb9d
996Please respect copyright.ＰＥＮＡＮＡW47xnOzvIJ
然而，用上用上90 日相對濕度=45%，攝氏為30°C，300W光源直接照射的環境來模仿歲月摧殘的話，則沒有感測得到Wet Method副產物的產生和顏料變色現象發生。996Please respect copyright.ＰＥＮＡＮＡ1r0dmKfCfa
996Please respect copyright.ＰＥＮＡＮＡT7yEvbHRhn
996Please respect copyright.ＰＥＮＡＮＡP5q6DAKbpB
（圖5）另外，他們亦對愛德華·孟克那時期捐贈予館舍的顏料油作出檢測。996Please respect copyright.ＰＥＮＡＮＡtWtZ80hDce
996Please respect copyright.ＰＥＮＡＮＡUu5zg194xW
996Please respect copyright.ＰＥＮＡＮＡtyFwofrxeZ
在畫紙塗上顏料油後，已能測量得到有一定程度份量的Wet Method副產物Cd(OH)Cl（左圖綠點）。996Please respect copyright.ＰＥＮＡＮＡxnJTX8trEj
996Please respect copyright.ＰＥＮＡＮＡnV8ZcYzbfU
（右圖）用上90 日相對濕度≥ 95%，攝氏為40°C的方式摧殘後，綠點數量大增且集中在一起。996Please respect copyright.ＰＥＮＡＮＡCAD6Exgsop
996Please respect copyright.ＰＥＮＡＮＡvoMDIQvic4
996Please respect copyright.ＰＥＮＡＮＡVa8GcSxAqU
（圖6）換句話說，當時期以Wet Method製作的Cadmium sulfide顏料以及愛德華·孟克所使用的顏料油，乃是導致畫中黃色地方出現變白及有脫落跡象的元兇，而其變色的機制主要由相對濕度和溫度而非光線控制。996Please respect copyright.ＰＥＮＡＮＡUt1zdCwdG7
996Please respect copyright.ＰＥＮＡＮＡRb8dVd0Fnl
996Please respect copyright.ＰＥＮＡＮＡPZWJ898RDi
基於這發現，在相對濕度及溫度嚴密的控制下，吶喊他日將來也許會有機會可以再度長期公開示人。996Please respect copyright.ＰＥＮＡＮＡYUSmUUXW2a
996Please respect copyright.ＰＥＮＡＮＡxpCEWTSjA2
如果想我快啲出文的話，請入去Penana網站科普專欄–薯不揀單俾一個like以及Bookmark，這對我非常之重要。996Please respect copyright.ＰＥＮＡＮＡZv1hycLOTx
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Link: https://www.penana.com/story/66244/%E7%A7%91%E6%99%AE%E5%B0%88%E6%AC%84-%E8%96%AF%E4%B8%8D%E6%8F%80%E5%96%AE/toc996Please respect copyright.ＰＥＮＡＮＡqBWocnCpmu
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同時亦可以在Penana網站裡按「買一嚿/半嚿薯仔」，以課金的方式推動我繼續搜羅資料寫文，多謝。996Please respect copyright.ＰＥＮＡＮＡVOVe3C7fvi
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Link:996Please respect copyright.ＰＥＮＡＮＡpNatB9sMig
https://www.penana.com/user/27349/%E8%96%AF%E4%BB%94%E8%81%9E%E8%8C%B1%E8%8E%89/portfolio996Please respect copyright.ＰＥＮＡＮＡwVrmYlI7GD
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有興趣接收科學資訊的話，歡迎follow IG: potatopigtongue。996Please respect copyright.ＰＥＮＡＮＡV9rSs21hGj
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Ref1:https://advances.sciencemag.org/content/6/20/eaay3514996Please respect copyright.ＰＥＮＡＮＡfEjlplubNE
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