Introduced to artists paints in the 1960s, Unbleached Titanium (pigment index number PW6 or PW6:1) is a shade of yellow-grey that can be described as being like parchment, suede, or sand. As its name and pigment index number suggests, it is closely related to Titanium White. However, its characteristics are very different and the possibilities it offers in colour mixing are unlike any other pigment. This article explores its history, unique characteristics, and how its colour mixing capabilities can enrich any painter’s palette.
The History of Titanium White and Unbleached Titanium
In order to understand the history and properties of Unbleached Titanium, you have to look first at Titanium White. Titanium White is a white pigment composed mostly of titanium dioxide. In nature, this compound is found most abundantly in minerals like ilmenite or rutile, from which high-purity titanium dioxide can be extracted or synthesised. By the end of the 19th century, titanium dioxide was already being used as an acid-resistant agent in ceramic glazes and enamels, but from 1908 researchers in Norway and the US began exploring the compound’s potential as a white pigment due to its high opacity.
However, the quest for a pure-white pigment was not an easy one– alongside titanium dioxide, ilmenite contains iron-oxides, metallic compounds that give earth pigments their colour. Because of remaining iron-oxide impurities, the first experimental batches of Titanium White ranged from off-white to reddish-yellow. Even by 1927 the pigment was still described as being slightly yellow in hue. This could be improved by using additives like calcium phosphate and barium sulphate, but these compromised the opacity of the pure titanium dioxide. The process of making a bright Titanium White pigment with high opacity was refined and perfected over the first half of the 20th century, and the pigment was gradually taken up by artist-paint manufacturers in the 1930s.
While developers of Titanium White worked hard to remove iron-oxides from the white pigment, it is the natural occurrence of iron-oxides with titanium dioxide that gives us the ‘unbleached’ variety of Titanium White. However, rather than being truly ‘unbleached’ (Titanium White pigment is not bleached in the first place), the pigment is a titanium dioxide pigment that is formulated so that it still contains around 1.5% iron-oxide, giving it a characteristic buff colour. The first company to produce it in an artist paint was Bocour, a company co-founded by Sam Golden who would go on to establish Golden Artist Colours. In the 1960s, they bought what they thought was Titanium White pigment, but it turned out to be an off-spec titanium dioxide that was sandy-beige in colour. Not wanting to let the pigment go to waste, they made a paint with it that they called ‘Unbleached Titanium’, a name that sums up its unusual hue. The colour proved to be popular among artists, and today the colour is included in many artist paint ranges. Many still use this original name, while others use ‘Buff Titanium’ or ‘Titanium Buff’.
The Properties of Unbleached Titanium
It shares many properties with Titanium White, such as its extremely high opacity and high refractive index, but there are some notable differences. Titanium White pigment has very small pigment particles (usually less than 0.4µm), whereas the ‘unbleached’ variety measures around 1µm. Additionally, in oil paint it dries much faster than regular Titanium White because it requires only a small amount of oil to grind it into a usable paint. This makes it a useful underpainting colour. There is a certain amount of variation between brands, with some being slightly pink and others more yellow or orange in hue. These variations are due to the exact composition of each pigment and the amount of iron-oxide it contains.
Colour Mixing with Unbleached Titanium
Used on its own, it might not seem like the most exciting colour. It is rather dull and dense, and any shade that can be described as ‘beige’ might not be immediately inspiring. However, it is a colour-mixing powerhouse that can add texture and atmosphere to many different palettes. Compare, for example, how differently Titanium White and Unbleached Titanium modify Ultramarine Blue. The Titanium White lightens it to a bright, primary blue, while the ‘unbleached’ alternative lends a little green-ness, making more muted and atmospheric blues.
Titanium White is often the go-to white for many artists, but its brightness can appear clinical when something more subtle is needed. For example, if you use earth colours in your paintings, Unbleached Titanium could be a better choice for lightening their value while maintaining their earthy-quality.
When mixed with pinks and purple pinks, it makes a range of velvety, subtle pinks that would be at home in botanical and portrait palettes.
Unbleached Titanium’s yellow-bias should be taken into account when using it in colour mixing. It means that it makes a natural mixing partner to a variety of greens, adding an earthy softness and higher opacity to them.
The same is true for blues that lean towards green. In the mixture below, it enhances the green-ness of Cobalt Teal:
Thanks to its large and irregular pigment particles, Unbleached Titanium is a granulating pigment in watercolour. These highly granulating properties can be exploited to make some gorgeously textural washes, particularly when paired with other very granulating pigments. Even adding just a small amount to another colour lends it a velvety texture:
As shown in the colour mixes above, the subtle and velvety quality of Unbleached Titanium can be useful for imparting a muted earthiness to pigments that are otherwise very bright and vibrant. If there are any mixtures you enjoy using, then please let us know by leaving a comment below.