Gypsum Gesso Was Built in Layers beneath Paint and Gold, Then Sanded until the Image Had a Perfect Ground｜畫和金箔下面先疊好幾層石膏膠，再磨到幾乎看不見它的存在
WHAT 這是什麼
波士頓美術館材料資料庫說明，傳統石膏底料由石膏與動物膠混合，分層塗作繪畫和貼金的基底。工匠再以刮削、研磨或拋光整平，使上方圖像與金箔得到平滑承載面。
WHY HERE 為什麼屬於底域的世界
石膏不是畫面內容，卻決定畫面能不能成立；礦物在最底層承擔一個觀眾通常完全看不見的視覺工作。
BLIND SPOT 補了哪一塊少看的視角
gesso recipes differ by period and region, and modern acrylic gesso is materially different; this entry refers to traditional gypsum-and-glue grounds.
