Chinese. Dish. Ming dynasty early 15th century, Jingdezhen, Jiangxi province, porcelain, underglaze cobalt blue. Felton Bequest, 1946. (‘Blue: Alchemy of a Colour’, NGV January 2016) The ceramic shows why every effort to imitate sky at noon is prone to mutability, and possibly disappointment. Air fades celeste so cloud gathers. Or intensifies celeste to deep evening. Small fissures develop no-one has ever seen in the sky. Resultant craquelure ages celeste. Or gives the appearance of a change in the weather. The artist’s strategy of emulating the sky’s arc only reminds us of human scale before heaven’s immensity, the intangibility of horizon.