Rublev Colours Prussian Blue is a classic deep blue pigment with a subtle greenish bias, made using the Milori process developed by the French colour maker Milori & Company. Known historically as Berlin blue, iron blue, or Milori blue, Prussian Blue has been a cornerstone pigment since the early 1700s and remains essential for artists and paint makers who want powerful, transparent to semi-opaque blue mixtures and rich darks.

Prussian Blue offers exceptional depth in mass tone and creates beautiful light blues when tinted with white. It is a favourite for skies, atmospheric distance, cool shadows, and neutral mixing, producing clean greens when combined with yellows and strong darks when paired with earth pigments. It works well in oil, watercolour, egg tempera, and encaustic. Because it can be sensitive to alkalis, it is not recommended for fresco or strongly alkaline systems.

Key features

• Colour Index PB27 (77510:1), ammonium iron(III) hexacyanoferrate(II)

• Deep blue with slight greenish undertone, excellent for mixes and tints

• Made by the Milori process for reliable colour strength and consistency

• Suitable for oil paint making, watercolour, egg tempera, and encaustic

• Avoid use in fresco or alkaline binders due to alkali sensitivity

Safety note: Considered low hazard, but avoid inhaling dry pigment dust. Use a mask and good ventilation when handling powder.