科普專欄–薯不揀單 - 深入淺出–以化學角度審視吶喊名畫

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。940Please respect copyright.ＰＥＮＡＮＡgyZsiTJjHi
940Please respect copyright.ＰＥＮＡＮＡJSJYbJE41H
940Please respect copyright.ＰＥＮＡＮＡPKr7O5Kd8E
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。940Please respect copyright.ＰＥＮＡＮＡm91BuXaGpn
940Please respect copyright.ＰＥＮＡＮＡwoPozxEvNN
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。940Please respect copyright.ＰＥＮＡＮＡaNOxN7VHVr
940Please respect copyright.ＰＥＮＡＮＡvTbOphKisl
940Please respect copyright.ＰＥＮＡＮＡKGqkRB5fro
（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)。940Please respect copyright.ＰＥＮＡＮＡDRj0AxKVKq
940Please respect copyright.ＰＥＮＡＮＡeAUEEnpXJT
940Please respect copyright.ＰＥＮＡＮＡr9HjjJVG03
Cadmium sulfide，為該時期常用作為黃色顏料的化學物。940Please respect copyright.ＰＥＮＡＮＡ0SteRyaAS2
940Please respect copyright.ＰＥＮＡＮＡbN304Gu13D
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。940Please respect copyright.ＰＥＮＡＮＡ8rifL24olX
940Please respect copyright.ＰＥＮＡＮＡuQ6KLd3e6c
該時期主要有兩種方式製作Cadmium sulfide，分別為Dry及Wet Method。940Please respect copyright.ＰＥＮＡＮＡYqxYDVrbzJ
940Please respect copyright.ＰＥＮＡＮＡ5eH3M3YBTU
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。940Please respect copyright.ＰＥＮＡＮＡXc8QLxMsu6
940Please respect copyright.ＰＥＮＡＮＡYANnazcXOE
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。940Please respect copyright.ＰＥＮＡＮＡwXhzHPpnma
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。940Please respect copyright.ＰＥＮＡＮＡ6tXvN8QJc5
940Please respect copyright.ＰＥＮＡＮＡlX7iQJgE3l
（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。940Please respect copyright.ＰＥＮＡＮＡGe3FiWB8tp
940Please respect copyright.ＰＥＮＡＮＡ2x7MpcElzy
940Please respect copyright.ＰＥＮＡＮＡgw2vGjvXZ9
圖3中間的圖片，其紅點代表黃色顏料Cadmium sulfide的存在。940Please respect copyright.ＰＥＮＡＮＡ2vn54RAuLT
940Please respect copyright.ＰＥＮＡＮＡwiXxlca3w6
下方的圖片，其三種顏色的出現分別代表Wet Method的副產物。940Please respect copyright.ＰＥＮＡＮＡqyAhDo6bYa
940Please respect copyright.ＰＥＮＡＮＡ7eBJidtHcc
紅點:Cd(OH)Cl940Please respect copyright.ＰＥＮＡＮＡnBwjheah9A
綠點:CdSO4940Please respect copyright.ＰＥＮＡＮＡz9Nf3rCxc9
藍點:CdCO3940Please respect copyright.ＰＥＮＡＮＡQcwx2aAG4D
940Please respect copyright.ＰＥＮＡＮＡOkFYzoV5m2
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。940Please respect copyright.ＰＥＮＡＮＡhVax6JaPXb
940Please respect copyright.ＰＥＮＡＮＡjbkdumbwkc
（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)。940Please respect copyright.ＰＥＮＡＮＡvCgKEx9KPe
940Please respect copyright.ＰＥＮＡＮＡuR4xdkApKm
940Please respect copyright.ＰＥＮＡＮＡoMfpYSH0CA
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）。940Please respect copyright.ＰＥＮＡＮＡrSE1cFvxMK
940Please respect copyright.ＰＥＮＡＮＡG6QpIw3fgv
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。940Please respect copyright.ＰＥＮＡＮＡcVdGtv2hC8
940Please respect copyright.ＰＥＮＡＮＡ5xPL6Mt03y
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。940Please respect copyright.ＰＥＮＡＮＡJcYptaUsVl
940Please respect copyright.ＰＥＮＡＮＡh5gTkDmMc4
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。940Please respect copyright.ＰＥＮＡＮＡszzVaTA1gC
940Please respect copyright.ＰＥＮＡＮＡLKqQDkKehx
940Please respect copyright.ＰＥＮＡＮＡJfqUFXFOx3
（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。940Please respect copyright.ＰＥＮＡＮＡQ9FP3H0dUf
940Please respect copyright.ＰＥＮＡＮＡhusKoSeRz6
940Please respect copyright.ＰＥＮＡＮＡU8ApbmJgvM
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）。940Please respect copyright.ＰＥＮＡＮＡYoU8UEuNCR
940Please respect copyright.ＰＥＮＡＮＡRipu4yjuL9
（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。940Please respect copyright.ＰＥＮＡＮＡRi3Zz9HQmv
940Please respect copyright.ＰＥＮＡＮＡl1i3sCq49q
940Please respect copyright.ＰＥＮＡＮＡFVlXfk9v2h
（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。940Please respect copyright.ＰＥＮＡＮＡkxeStGhaIn
940Please respect copyright.ＰＥＮＡＮＡ8EwSMgAaQc
940Please respect copyright.ＰＥＮＡＮＡo85bac3OOn
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。940Please respect copyright.ＰＥＮＡＮＡgXWjoWYwb8
940Please respect copyright.ＰＥＮＡＮＡJTwlCU65W9
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。940Please respect copyright.ＰＥＮＡＮＡHW1oZjQ6XM
940Please respect copyright.ＰＥＮＡＮＡh1CC1fGWE9
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/toc940Please respect copyright.ＰＥＮＡＮＡtfs7lrlzAH
940Please respect copyright.ＰＥＮＡＮＡNjkRuSYOmB
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。940Please respect copyright.ＰＥＮＡＮＡXiFVHI7PbI
940Please respect copyright.ＰＥＮＡＮＡfUv88bo7VM
Link:940Please respect copyright.ＰＥＮＡＮＡr9TaQKwqbA
https://www.penana.com/user/27349/%E8%96%AF%E4%BB%94%E8%81%9E%E8%8C%B1%E8%8E%89/portfolio940Please respect copyright.ＰＥＮＡＮＡjTBlJpbSHJ
940Please respect copyright.ＰＥＮＡＮＡvvA3YPPc3X
940Please respect copyright.ＰＥＮＡＮＡZ6KtrZnz69
有興趣接收科學資訊的話，歡迎follow IG: potatopigtongue。940Please respect copyright.ＰＥＮＡＮＡhTgLLoBuEy
940Please respect copyright.ＰＥＮＡＮＡjFr14jjr5g
Ref1:https://advances.sciencemag.org/content/6/20/eaay3514940Please respect copyright.ＰＥＮＡＮＡD35JRUdech