Ultramarine Pigments in depth

Ultramarine Blue: A Timeless Pigment

Also Known As:

• French Ultramarine
• Ultramarine Green Shade
• Ultra Blue

Chemical Composition:

Sodium-aluminium-sulfo-silicate

Pigment Identification:

• Pigment Blue: 29
• Colour Index: 77007

The Origins of Ultramarine

Ultramarine is a rich, deep blue pigment originally derived from lapis lazuli, a semi-precious stone that was ground into a fine powder. Due to its rarity and labour-intensive extraction, natural ultramarine was one of the most expensive pigments in history.

That changed in 1826, when French chemist Jean-Baptiste Guimet developed a synthetic version by heating kaolinite, sodium carbonate, and sulfur in a kiln. This breakthrough made Ultramarine widely accessible while maintaining its vibrant color.

Types of Synthetic Ultramarine

Synthetic Ultramarine is classified into two main categories:

• Ultramarine Red Shade (French Ultramarine)
• Ultramarine Green Shade

Though these variants appear different, they are chemically identical, with their distinct shades resulting from variations in the balance of blue (S₃) and yellow (S₂) polysulfide chromophores.

Micronisation & Colour Strength

Ultramarine pigments are further refined through micronisation, a process that reduces particle size. The finer the particles:
✔ The stronger the colour
✔ The greener the hue
✔ The brighter the pigment

Transforming Ultramarine into New Shades

Ultramarine can also be modified through chemical treatments to produce a range of colours:

• Ultramarine Violet – Created by treating medium-particle red shade Ultramarine with ammonium chloride. Prolonging this reaction makes the pigment redder but weaker. Ultramarine Violet is about half the strength of medium-particle Ultramarine Blue.
• Ultramarine Pink – Formed when Ultramarine Violet is treated with HCl gas, resulting in a pigment half as strong as the violet.

From its historical origins to modern refinements, Ultramarine remains a cornerstone of the artist’s palette, offering exceptional depth, brilliance, and versatility.

5 Different shades of Ultramarine Pigment we tested, we’ve since tested another 4 more

Ultramarine Green Shade Pigment