Mica Magic
Especially unique to Kumataro Itō’s detailed illustrations and particular artistic style is the addition of flaked mica, a naturally shiny silicate found in small flakes in rocks that is used to impart shine and shimmer in many items such as cosmetics and artistic media. This shimmering mineral is used on some of the images of fish which lends a realistic shine to certain subjects, as in the example images shown here, but it also helps for artistic identification when once again artist signatures and appropriate attribution are absent. Due to lighting and image transferrance the shine created from the mica is quite difficult to accurately capture for digital posterity.
It is worth noting that not every fish in the book, nor every specimen on a particular page or even the entirety of a chosen fish is treated with the mica thus when it appears it is with an elusive flash on the page much like the real glimmer of a fish in the water.