Kirazuri (雲母摺り) is a method used in Japanese woodblock printmaking using mica powder, or 雲母 (kira) to add sparkle.
When used for the background in portraits, depending on the base color, it is called Shiro-kirazuri (white), Kuro-kirazuri (literally black, but dark gray practically), and Beni-kirazuri (red).
[1] There are several different types of kirazuri:
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