Blacks are either common ivory or Frankfort black; and grays are formed by mixtures of Prussian blue and Spanish white.
There are different kinds, but I prefer the Prussian blue above all.
Mr. Savage recommends a little Indian red to be ground in with the indigo and Prussian blue, to give a rich tone to the black ink.
Suddenly from top to bottom of the ice cliff two deep lines of Prussian blue appeared.
The charcoal from the other substances will serve for the manufacture of Prussian blue.
A dirty brownish or greenish precipitate will fall, consisting of a mixture of the oxide of iron and Prussian blue.
When Prussian blue is made with two atoms of ferrocyanide of potassium, instead of one, it becomes soluble in water.
The colored inks often used are light yellow, peacock or Prussian blue, and bright, transparent crimson.
Prussian blue Prus·sian blue (prŭsh'ən)
See Berlin blue.