安德魯·懷斯的蛋彩畫是否只使用純蛋黃媒介，如何防止畫作表面發生霉變，如果發生了應怎樣處理？

如題

懷斯的坦培拉僅使用蛋黃並加蒸餾水稀釋，這種方法是比較傳統的。防止畫面發霉要從兩個方面注意，第一是繪畫過程中，坦培拉乳液要保持新鮮，比如這個純蛋黃乳液室溫使用，用完密封冰箱冷藏，也不能超過兩天，第三天手感就會差很多，而古代畫家也會加入各種液體來防止其腐敗，比如義大利畫家用無花果樹嫩枝里的白色液體，某寶上還真有人賣（20一克），德國畫家用啤酒，或是葡萄醋，俄羅斯畫家用格瓦斯，這些液體都延長乳液的使用時間，如今常用的是啤酒，白醋和白葡萄酒，其中啤酒最好用，白醋必須要低濃度9%或更低一些，酸味兒很不爽，白葡萄酒也挺好，但是會讓顏色變暗，但即便如此，乳液也不可超過五天（每天要密封冷藏），馬克斯多奈爾的著作中提到盛過達瑪光油的瓶子放雞蛋乳液可以保存大半年到一年，但是即便是一丁點的達瑪光油也是會改變乳液原有的性質的，所以最好是現用現做。第二就是保存過程，要防潮防濕，這點很重要，也可以在畫作表面塗光油或是罩光漆，通常使用幹性油（熟亞麻油）與乙醇溶解的某種樹脂溶液，但是這樣會使畫作變得反光，而且時間長了還會發黃，如果繪製過程中功夫不夠可能還會出現上光之後畫面喪失整體性。
至於發霉了怎麼辦，我本身不是學古修的，了解不多，但是坦培拉不上光是可以擦除的，所以擦去重繪應該是最方便可行的方法
剛才忘發了，以下是美國一本書中對懷斯坦培拉技法的描寫，英文的，本人英語比較捉急能看但翻譯比較麻煩，自己看吧：
"Mindful of the dangers inherent in practiced facility with his watercolor brushes he has put them away in moth balls for a season and, during the past year, has been devoting himself to tempera painting, employing a technic that imposes strict disciplines.

"In his temperas Wyeth』s objective is to cover up his brush strokes and obtain a sense of freedom through pattern rather than technic. He paints these pictures with a single sable brush not over 3/4 of an inch long.

"These are done on Masonite upon which three coats of whiting mixed with casein glue are applied as a ground. The pulverized glue is heated, in water, in a double boiler. Wyeth sandpapers the final coat to a very smooth finish. The panel is made rigid by a framework attached to the back. He paints with dry colors mixed on his palette, as he works, with distilled water and egg yolk.

"His procedure is to make a monochrome underpainting in black ink. The colors, applied over this black and white, have a quality of weight and depth preferred to the result of direct painting in color. This is in accordance with the traditional method of old masters who used this medium.

"This turning from the freedom of watercolor to the exactions of tempera illustrates the intelligent purpose of a young artist in seeking strength and breadth as foundation for the work he hopes to do later on. Through his tempera paintings he is acquiring the habit of accuracy and is seeking an intimacy with nature which he feels he cannot attain with his watercolor brush alone. Thus fortified he believes his watercolors, though painted in a burst of enthusiasm, are more likely to be informed and interesting in every detail.

"『Too often,』 he says, 『a watercolor appeals solely by virtue of tricks and fortuitous beauties inherent in the medium itself. My aim is to make every part of the picture alive, interesting.』

"The casual observer, turning from Andrew Wyeth』s impulsive watercolors to his tempera paintings, executed in the spirit of old master craftsmanship, might well be puzzled. They appear in temperament as well as in technic like the work of two separate individuals. They are, in the sense that the well-rounded man is a different man at different times, as he takes devious directions to arrive at a goal that cannot be approached by a single paths. Only the artists himself can see the map whereon those divergent paths finally meet in the ground strategy of a single purpose.

"We shall watch for the meeting of those paths in the work of Andrew Wyeth."
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關於如何清除畫面霉斑的問題，剛剛查了一下坦培拉繪畫修復的資料，使用棉簽蘸溶於酒精的松香溶液輕輕擦拭即可