色彩雫 【紫式部】 Iroshizuku murasaki-shikibu - Fountain Pen Ink - 紫式部(murasaki-shikibu) is a nickname; her real name is unknown, but she may have been Fujiwara Takako, who was mentioned in a 1007 court diary as an imperial lady-in-waiting. Murasaki means Violet.
Invisible Ink (“Encre Sympathique”) The ink turns blue when held under a light or other heat source. Writing disappears as the paper cools. J. Herbin started making invisible ink in 1993. It’s made of mineral water, and cobalt chloride. Cobalt chloride dissolves in water, giving it a light pink color that is so pale you can’t see if when you write on paper.