好玩儿的叶片肖像

今天看到了这个精美的叶片肖像画，觉得很有意思，找时间自己做一个。

‘Starch picture’ of Dr Jan Ingen-Housz on a geranium leaf (prepared by William Ruf and Howard Gest). The image of Ingen-Housz consists of photosynthetically-produced starch granules, which were ‘developed’ by staining with I2-KI. An engraving of Ingen-Housz (in Reed 1949) was photographed, and the negative placed in a slide projector. Light passing through the negative was focused on a geranium leaf (depleted of starch by prior incubation in darkness) for about one hour. After extraction of pigments from the leaf with boiling 80% alcohol, the blanched leaf was flooded with I2-KI solution to stain the starch granules. Within minutes, the details of the engraving dramatically appeared on the leaf. The inscription at the bottom refers to Dr Ingen-Housz’s fame as a ‘smallpox inoculator’. The ‘starch picture’ procedure was invented by Hans Molisch in 1914. Further details and an English translation of Molisch’s paper ‘On the production of photographs in foliage leaves’ can be found in Gest 1991.1。

在天竺葵叶片上通过淀粉显色刻画的荷兰科学家英格豪斯博士肖像画。英格豪斯的肖像由光合产生的淀粉颗粒组成，通过淀粉遇碘变蓝的原理进行显色。先将天竺葵在黑暗中预先培养使淀粉耗尽。再把英格豪斯照片的底片放在投影仪上，投影仪的光聚焦在暗处理过的天竺葵叶片上约一个小时。用煮沸的80%酒精提取这片天竺葵叶片的叶绿素，再加碘液显色即可。