EARTH PIGMENTS
Natural earth pigments encompass a spectrum of hues derived solely from the Earth itself. These pigments give rise to gentle, partially translucent shades, revealing nuanced undertones when blended with opaque foundations. While their tinting power may not rival that of synthetic oxide pigments in terms of strength or consistency, their depth of colour possess an unmatched quality that eludes artificial counterparts.
OBSIDIAN ΛRC carefully and responsibly sourced by hand, these pigments originate from quarries, valleys, and mountain ranges scattered across the breathtaking landscapes of New Zealand. Moreover, they are non-toxic, ensuring a safer, more conscientious artistic experience.
Earth as a pigment dates back to prehistoric eras, where it manifested in a surprising spectrum of colours. These earth pigments range from robust, warm reds to cool, subdued greens. In this exploration, we delve into some of the most frequently employed earth pigments, their synthetic counterparts, and methods for their identification.
What Defines Earth Pigments?
Earth pigments encompass hues that naturally occur within the Earth's depths. These colours owe their identity to the presence of various metal oxides, clays, and minerals in the soil. Notably, this composition often remains unique to the geological characteristics of a specific location. Earth pigments possess remarkable lightfastness and permanence, rendering them a favored choice for artists seeking enduring and unyielding colors on their palettes.
What are Synthetic Iron Oxides?
Synthetic iron oxide pigments, also known as Mars pigments, were first created in the 18th Century, but they began to gain popularity as alternatives to natural earth pigments in the early 20th Century. They are produced by precipitating salts of iron with alum and an alkali, such as lime or potash. Synthetic iron oxides include yellow, red, black, and violet pigments, and the exact formulation and type of iron salt used determines the colour of the pigment.
While they are chemically similar, synthetic iron oxides tend to be highly saturated and ‘cleaner’ in colour than natural iron oxides, which can contain naturally occurring 'impurities'.
Generally speaking, synthetic iron oxides have a smaller pigment particle size than natural earth-based pigments. This makes them usually higher in tinting strength and, in watercolour, more staining and harder to lift. But because of the huge variation in the properties of both natural and synthetic iron oxides, it’s difficult to make definitive comparisons between the two. But even so, it’s helpful to identify the pigments that are used in artists paints today.
Left: A selection of synthetic red iron oxide pigments (PR101).
Right: Natural red iron oxide pigments (PR102).
While synthetic iron oxides can mimic the myriad hues of natural earth tones, and are prevalent due to their consistency and affordability, they sacrifice richness of hue and the exquisite beauty of unique variation available.
Kōkōwai | Red Ochre
Kokowai possesses a deep connection to the Māori creation narrative.
In the dawn of time, Ranginui (the sky) and Papatuanuku (the earth) were fused together, with their offspring born in darkness between them. Deciding light needed to be let into the world, the children violently separated their celestial parents, turning Te Pō (darkness) into Te Aō (light). This cataclysmic act resulted in savage wounds, with Ranginui's blood still seen as the crimson glow in the evening sky, while Papatuanuku's essence flowed through the earth, giving form to the sacred Kokowai — a living embodiment of ancient legends and profound transformation.
Kokowai is red coloured clay which was burnt and mixed with shark oil. This richly coloured substance has been used for centuries to adorn carvings and stain flax weavings. Kokowai is found in areas rich in iron and aluminium silicates – the geothermal minerals present in the soil in Te Whakarewarewa Valley was travelled to from afar for its plentiful supply.
Red and Yellow Ochre
Natural Red Ochre pigments (PR102) are derived from earths that contain high amounts of hematite, a blood-red mineral. Natural Yellow Ochre (PY43) contains hydrated iron oxide, which gives the earth its golden yellow colour. Red and Yellow Ochre can be found in the earliest prehistoric cave paintings.
Ochre (derived from the Greek word Okhra, meaning yellow soil) is a naturally occurring clay that presents a symphony of colors, ranging from delicate pale yellow, intense reds and maroons to rare green and blues. However, before it becomes ready for use, ochre must undergo several crucial steps.
Extraction: To begin, the ore is extracted from the cliffs in quarries.
Washing: Next, the ochre is separated from the sand through a cleaning process that involves water and centripetal action.
Decantation: Afterwards, the ochre is left to dry in the open air from spring to summer before being carefully stored.
Calcination: In certain cases, specific colours undergo calcination. For example, raw yellow ochre is subjected to high temperatures to produce orange ochre. Our unique range of colours is created by mixing different ochre pigments extracted from various locations and veins thorughout Aotearoa.
SIENNA + UMBER
Pigment index number PBr7 broadly categorizes pigments containing natural brown iron oxides, with Sienna and Umber being two of the most prevalent earth colors on an artist's palette.
Sienna draws its name from the ancient city of Siena, Italy. It's a yellow-brown earth pigment originally sourced from the Tuscan hills. This color surged in popularity among Renaissance artists during the 14th century. On a parallel note, Umber derived its name from the Umbria region in Italy, where it was first mined. The presence of manganese within the earth there lent Umber a deeper, more green hue compared to Sienna.
'Burnt' variations of these earth colours emerge from a process known as calcination, through heating the raw pigment.This alchemical transformation partially converts the brown iron oxides into hematite, a red iron oxide, adding a new intensity to their earthly hue.
In some Burnt Sienna paints, PBr7 is replaced by synthetic pigment PR101.
Raw Umber is sometimes made with PBr6, a pigment made by oxidising synthetic black iron oxide.
RARE GREEN EARTH
Known as 'Terre Verte,' natural green earths are composed of silica clay and green minerals. Like their ancient counterparts, these pigments have been in use since the dawn of time. Yet, they possess a fragile nature, marked by a low tinting strength that renders them subdued within mixtures. Nevertheless, they exude a distinctive character of their own and hold the power to subdue the fiery reds and oranges, adding a somber depth to the palette.
They find their place in the art of deception, particularly in the underpaintings for portraits – a technique known as 'verdaccio.' Here, they lay the foundation for life-like flesh tones, casting a shadowy allure over the visage.
Rare Green Earth
The pigment index number for green earth is PG23. Many paints labelled Terre Verte or Green Earth contain no natural green earths, but rather a mixture of green and brown pigments. Ranges from a blue-shade green, to a yellow-shade green, and is semi-transparent on its own.
Our F/W 2023 Green source we call "Guardian" is on the cerulean side of green with it's blue hue revealed in glazes and when tinted with white, where it leans towards a soft sage to sky-blue. Try mixing it with Crimsons for dark chromatic tones, or with our Dark Umber for rich, natural green shades.