A J Ludlow Ultramarine Blue Professional Watercolour

Ultramarine Blue is just one of the bright and exquisite Professional Watercolours made in the UK by A J Ludlow. Being based on a single pigment with excellent permanence and light fastness, ensures that this watercolour’s properties are exceptional.

Ultramarine Blue Professional Watercolour is prepared using the synthetic mineral pigment based on the three-dimensional aluminosilicate lattice with a sodalite structure containing entrapped sodium ions and ionic sulphur groups (from “Pigment Compendium”, page 381). The pigment has been selected for its purity, light fastness and intense red shade blue hue, making it ideal for use in A J Ludlow’s Professional watercolour range.

C.I . pigment blue 29 can refer to either the natural mineral, Lapis Lazuli or the synthetic form, which is sometimes referred to as French Ultramarine, after Jean-Baptiste Guimet the French industrial chemist who in 1828 was awarded a prize for a process for making synthetic ultramarine blue. In both compounds the chromophore (or colour centre) is the polysulphide groups (which gives the mineral its blue colour), which explains why the pigment’s colour changes from blue to grey (the normal colour of the sodalite structure), accompanied by the smell of rotten eggs (caused by the liberation of toxic hydrogen sulphide (H2S) gas), when treated with mildly acidic liquids (for example lemon juice).

When the blue pigment derived from the semi-precious blue stone, lapis lazuli was first introduced into Europe in the 15th Century, where it came from and how it was produced was shrouded in mystery and the pigment was known only to have come from “beyond the sea”, hence it became known as oltramarino by the medieval Italians (at the time, the name also referred to a number of other imported goods), as most of the pigmented lapis lazuli used in both western and eastern art came from the mines in Afghanistan (Finlay 2002, page 313). It is interesting to note that other similar synthetic pigments based on the same aluminosilicate-sodalite structure are also referred to as ultramarine (for example, Ultramarine Pink), but are no longer thought of as coming from “beyond the sea”.

Being a semi-precious stone, the pigment derived from lapis lazuli is expensive and now, frequently derived from mineral deposits containing high levels of silicate, which if not removed will dilute the blue lazurite, causing the pigment's hue to be less intense and dull. Synthetic ultramarine on the other hand is a more vivid blue, since the particles are smaller and more uniform, making this pigment the best choice for Ultramarine Blue in A J Ludlow’s Professional watercolour range.

The Ultramarine Blue’s red shade allows this Professional watercolour to be used on the artist’s palette as a warm primary blue. The watercolour’s tendency to granulate and high colour strength can be used to full effect when painting wet-in-wet or in dilute washes.

Eastaugh N, Chaplin T, Siddall R, Walsh V, “Pigment Compendium: A Dictionary and Optical Microscopy of Historic Pigments”, Routledge, Abingdon 2013

Finlay V, “Colour: Travels Through the Paintbox”, Sceptre, London, 2002

Pigment Details: Sulphur containing Sodium Aluminosilicate / Colour Index Pigment Blue 29 ( C.I. PB29)