vision

Bright Earth by Philip Ball is a remarkably multidisciplinary book about color. In a chapter about renaissance art, he described the technique of cangiantismo, which is most famously associated with the work of Michangelo. Wikipedia’s entry explains: “Cangiante is characterized by a change in color necessitated by an original color’s darkness or lightness limitation”. The effect is unnatural but it’s what fascinates me most about Michangelo’s paintings. This article explains how the technique was used in contemporary art such as Monster Inc.
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Notes for Collection of Sand - essays by Italo Calvino

Collection of Sand is a collection of book reviews, exhibition reviews and travelogues that Italo Calvino wrote in the 70’s and 80’s. The quality varies. The best of them are unsurprisingly ekphrastic essays where Calvino described gardens, historical sites, and paintings in exquisite details. Those where he tried to regurgitate scientific or historical knowledge from academic books are less inspiring. But still, it is the variety of things that Calvino cared to write about that charms.
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What is the shutter speed of human vision? A new paper claims that at extremely low light condition, it can be as long as 0.6 second.

Last week I went to see an optometrist. As he examined my eye with a strong light, I was amazed that I saw an image of the blood vessels on the retina. This phenomenon is called the entoptic image. It was first described by Purkinje about 200 years ago. I read about it in “How we perceive our own retina” by Kuno Kirschfeld (published in Proc. Bio. Sci.)

The lens

The lens is the component in the eye that reflects light. They are not always shape liked pancakes or magnifying glasses. In small mammals, the lens is very often looks like the chewy tapioca balls in Asian boba milk tea. Primate lenses are more like magnifying glasses: