INFRA-ART spectral data collections: earth pigments

by Ioana Maria Cortea — Published on September 2, 2025 — Reading time: 20 min

Keywords: earth pigments, INFRA-ART spectral data collections, iron-rich pigments, manganese oxides, mineral pigments, ochres, spectral data

Part of the INFRA-ART Spectral Data Collections article series

Article sections

» Earth pigments: key technical characteristics » Overview of major earth pigment types » Nomenclature and terminology » Earth pigments in art: history of use » Earth pigments in the INFRA-ART Database » Further reading and resources

Natural earth pigments. Image source: Heidi Gustafson

Earth pigments are among the oldest materials used in human artistic expression. These naturally occurring pigments, derived from iron oxides, manganese compounds, clays, and other minerals, have been used since the earliest symbolic expressions of humanity and remain vital in both artistic and conservation practices today. Valued for their sustainability and safety, earth pigments are widely used in natural paints and are regaining popularity in contemporary eco-conscious art practices. More importantly, they are archaeological markers — remnants of color choices made by ancient societies that can tell us about trade routes, resource availability, and artistic conventions. The mineralogical and geochemical fingerprints of earth pigments, often highly complex, can be matched to known geological sources, providing valuable evidence for provenance studies.

In this post, we examine the mineralogy, classification, and nomenclature of earth pigments, explore their historical applications across cultures, and introduce the collections of earth pigments currently represented in the INFRA-ART spectral database.

Earth pigments: key technical characteristics

Composition and classification of earth pigments: Earth pigments encompass a broad range of naturally occurring mineral mixtures, typically categorized into groups such as iron-rich ochres, manganese-rich wads, umbers, green earths, white earths (including chalk, kaolinite, and diatomite), organic-rich materials like coal and other solid hydrocarbons, and vivianite-bearing blue earths.

The chemistry of earth pigments is inherently complex, shaped by the environmental conditions under which they formed. They typically consist of several chromophore minerals—primarily iron and manganese oxides or hydroxides—alongside a variety of accessory minerals. These accessory phases may include clays, quartz, carbonates (such as calcite or dolomite), and other minor and trace mineral components. The genetic environment also influences key properties of iron oxide minerals, including their hydration state, structural order, and crystal size. Together, these factors determine a pigment’s color, texture, opacity, and binding behavior.

Group	Alternative names	Color	Main coloring components
Ochres	ochre, flesh ochres, variations given by the geographical location of the source (e.g., Bristol ochre)	varying from browns and reds through yellows	iron oxide- and hydroxide-rich earths
Siennas	terre de Sienne, terra di Siena, Siena-erde	yellow-brown	iron hydroxide-rich earths + minor amounts of manganese oxides (<5%)
Umbers	ombra, terre d’ombre, terra d’ombra, tierra de sombra	warm brown to greenish brown	iron oxides + manganese oxides (between 5 and 20%)
Wads	bog manganese, black wad, black earth, manganese ochres	dark brown to black	iron oxides + manganese oxides (c. 50%)
Green earths	terra verde, terre vert, green stone	green to bluish green	clay minerals, celadonite or glauconite
Humic earths	Cassel earth, Cologne earth, Vandyke brown	rich brown	low-grade coal deposits or lignites

Main groups of earth pigments and their principal characteristics. Source: MDPI

Uyuni Salt Flats (Bolivia). Image source: Chiara Zonca

Effect of processing and human intervention: The appearance and behavior of earth pigments can be further altered (to adjust hue, brightness, and working properties) through post-extraction processes such as:

Drying and grinding – to increase fineness and improve uniformity;
Washing – to remove unwanted impurities;
Calcination (heating) – which alters the chemical structure and color, most notably transforming yellow ochres (goethite) into red ochres (hematite);
Addition of fillers – used to modify hue, texture, or extend pigment volume;

Some of these processing practices were already in use during prehistoric times and reflect an early understanding of how to transform raw geological materials into consistent, workable materials—demonstrating the human capacity to adapt natural resources for artistic and symbolic expression. Found in surface-level deposits, earth pigments were both visible and readily accessible, making them especially appealing to early humans. Archaeological evidence confirms that iron-rich earths have been used for tens of thousands of years to create color.

Ochre fragments found at the Porc-Epic Cave workshop in Ethiopia. Image source: PLOS

Application properties: Earth pigments are valued not only for their color and stability but also for how they behave in practical use. Their key application properties include:

High opacity – resulting from their fine particle size and mineral composition, allowing good coverage even in thin layers.
Matte surface finish – these pigments tend to produce soft, non-glossy coatings, especially in tempera and fresco.
Low tinting strength – generally weaker than synthetic pigments, which can be advantageous for nuanced blending, glazing, or underpainting.
Excellent lightfastness – earth pigments are highly resistant to fading, making them well-suited for a wide range of uses.
Compatibility with various binders – they work well in aqueous (e.g. tempera, watercolor) and oil-based media.
Non-toxicity – most are considered safe to handle, unlike many historical synthetic pigments.
Ease of dispersion – their natural particle morphology allows for good mixing and even distribution in paint formulations.

Natural earth pigments. Image source: Heidi Gustafson

Overview of major earth pigment types

Earth pigments are commonly classified by their color and mineral composition, yet these categories often overlap due to variations in geological formation, and regional naming traditions. Despite these complexities, a number of broad groupings—such as ochres, umbers, siennas, and green earths—offer a useful framework for understanding their characteristics.

Red Ochres

Main chromophore: Hematite (Fe₂O₃), an anhydrous iron oxide.
Color: Deep reds, oranges, and rust hues; can range from dull brick to vivid vermilion-like tones.
Accessory minerals: Often includes quartz, clays (kaolinite, illite), calcite.
Formation: Can be natural (precipitation or weathering), or through the calcination of goethite.
Variations: Color variation depends heavily on particle size and hematite morphology — platy or fine particles produce deeper reds, while coarser ones appear more orange.
Notable historical sources: Italy (Pozzuoli), Spain, Morocco (Midelt region).
Nomenclature: Includes terms like Italian red ochre, Venetian red, Pozzuoli red, often with overlapping or regional meanings.

Yellow Ochres

Main chromophore: Goethite (FeO(OH)), a hydrated iron oxide.
Color: Ranges from pale yellow and golden hues to warm ochres and deep tans.
Accessory minerals: Clays (e.g. kaolinite), quartz, gypsum, calcite.
Formation: Typically formed by weathering of iron-rich rocks in oxidizing environments.
Processing: Often used raw, but can be heat-treated to convert to red ochre (hematite).
Variations: Regional variations in yellow ochre typically reflect differences in accessory minerals—e.g. kaolinite-rich ochres are typically linked to French sources, while gypsum- or sulfate-based ochres are more common in Spanish deposits.
Notable historical sources: France (Roussillon), Spain (Andalusia), Germany (Amberg).
Nomenclature: Includes terms like French ochre, Amberg yellow, often with overlapping or regional meanings.

Brown Ochres and Umbers

Main chromophores: Goethite combined with manganese oxides (e.g. pyrolusite, romanechite).
Color: Warm browns, olive tones, or dark earth colors.
Composition: Umbers typically contain 5–20% manganese oxides. Below 5%, the pigment may be classed as sienna. Accessory minerals: clays, quartz, calcite.
Formation: Weathering of iron- and manganese-rich rocks in oxidizing environments.
Processing:
- Raw umber: Cooler and greenish-brown.
- Burnt umber: Richer, redder brown due to thermal treatment.
Notable historical sources: Cyprus, Italy (Monte Amiata), Germany, France.
Nomenclature: Includes raw and burnt umber; sometimes regionally labeled (e.g., Cyprus umber).

Siennas

Main chromophore: Goethite, with small amounts (<5%) of manganese oxides.
Color:
- Raw sienna: Transparent yellow-brown.
- Burnt sienna: Deep reddish-brown.
Formation: Weathering of iron-rich sediments, with low manganese content.
Composition: Higher iron content than umber, lower manganese; often associated with clay-rich matrices.
Processing: Heating enhances the red tones by converting goethite to hematite.
Notable historical sources: Siena, Italy.
Nomenclature: Now refers more to pigment type than provenance; includes raw and burnt variants.

Green Earths

Main chromophores:
- Celadonite: Derived from altered volcanic rocks (e.g. Italy, Cyprus).
- Glauconite: Derived from marine sedimentary rocks (e.g. Russia, Germany).
Color: Soft greens to greyish-blue greens.
Accessory minerals: Quartz, feldspars, clays.
Formation: Naturally occurring in iron–magnesium-rich environments; celadonite often in basaltic contexts, glauconite in marine sediments.
Notable historical sources: Italy, Cyprus, Germany, Russia.
Nomenclature: Includes terms like terre verte, Verona green, and Bohemian green.

Black Earths and Wads

Main chromophores: Manganese oxides (pyrolusite, romanechite, todorokite).
Color: Deep brown to black.
Composition: Often 30–50% MnO₂; may include hydrated iron oxides and clays or humic substances.
Formation: Weathering of manganese-rich rocks.
Notable historical sources: Morocco (Midelt region), Cyprus, Germany.
Nomenclature: “Wad” is a historical miner’s term for black manganese-rich earths.

Humic Earths

Composition: Organic compounds—mainly humic and fulvic acids, alongside clay minerals and iron oxides.
Color: Rich dark brown to nearly black.
Formation: Derived from lignite, peat, or low-grade coal deposits.
Variations: Color intensity may vary with humic content and source.
Notable historical sources: Kassel (Germany), Cologne, and other European lignite deposits.
Nomenclature: Includes names like Vandyke brown, Cassel earth, Cologne earth.

Nomenclature and terminology

The nomenclature of earth pigments is a complex intersection of geology, commerce, history, and artistic tradition. While modern scientific methods aim for clarity and reproducibility, the nomenclature of pigments, and earth pigments in particular, has long been shaped by inconsistent conventions, overlapping terms, and regionally-specific language.

Historically, earth pigments have been labeled based on several (overlapping) criteria:

Geographical origin
Examples: Verona Green, Cyprus Umber, French Ochre, Pozzuoli Red.
These names often reflect the source of extraction — though not always reliably — and have carried associations of quality or prestige (e.g., terra di Siena as a mark of authenticity).
Color and tone
Examples: Light Red Ochre, Deep Yellow Ochre, Raw Umber, Burnt Sienna.
These names are often descriptive but subjective, influenced by visual perception, particle size, or even preparation method.
Processing method
Most notably, the terms raw and burnt indicate whether the pigment has been thermally altered:
- Raw sienna (goethite-rich) becomes burnt sienna (hematite-rich).
- Raw umber turns into burnt umber with a redder tone due to dehydration of iron and manganese oxides.

Most of these labels, while useful in artistic practice, lack mineralogical precision. The nomenclature of earth pigments is complicated by longstanding inconsistencies and overlapping terminology. A single material may be known by multiple names, as seen in the Colour Index, which lists dozens of synonyms for ochres, siennas, and umbers. For example, several pigments may share the same Colour Index designation—such as PR 102 (C.I. Pigment Red 102) for red ochre—yet differ significantly in composition and origin. One sample might be a fine-grained hematite with high kaolinite content, while another may have a completely different mineralogical profile. Similarly, names like red ochre, Indian red, Venetian red, and Pozzuoli red are often used interchangeably for iron-rich red earth pigment, despite variations in hue, texture, and regional source. Additionally, branding practices by pigment manufacturers introduce ambiguous trade names like Antique Ochre, or Green Earth Light, which offer no reliable indication of mineralogical composition or geographic origin.

Earth pigments in art: history of use

Earth pigments are among the earliest, most enduring materials used in human artistic expression. Their natural beauty, stability, and widespread availability have made them indispensable across cultures and millennia — from Paleolithic burials to contemporary conservation practice.

Cuevas de las Manos (Argentina). Image source: Javier Etcheverry

Lascaux (France). Image source: Wikimedia

The earliest possible use of ochre identified to date comes from a Homo erectus site found in Kenya estimated to be around 285,000 years old. While this suggests very early engagement with iron-rich pigments, clearer evidence of deliberate ochre processing—such as the presence of raw materials, processing tools and/or storage container—emerges around 100,000 years ago, as evidenced by archaeological discoveries from both Africa and Europe. Red and yellow ochres were used by early Homo sapiens and Neanderthals alike for a range of symbolic and practical purposes. These included body decoration, ritual activities, or burial practices—such as the ochre-covered burial known as the ‘Red Lady’ of Paviland. Ochre was also used extensively in the creation of cave paintings, most famously at sites like Lascaux, Chauvet, and Altamira. In such prehistoric contexts, pigment selection was not purely aesthetic but deeply symbolic. Red ochre, in particular, has long been associated with blood, fertility, life, and transformation, underscoring its powerful cultural significance.

Pots with pigment found at Pompeii. Image source: Archaeological Park of Pompeii

Fresco (Livia’s Villa, Rome). Image source: Mark Cartwright

In the ancient world, earth pigments became integral to artistic systems across Egyptian, Mesopotamian, and Mediterranean civilizations. Egyptian wall paintings featured red and yellow ochres, as well as green earths, often combined with synthetic pigments like Egyptian Blue. In Greece and Rome, earth pigments were widely used in frescoes, sculpture polychromy, and architectural decoration. Etruscan tomb paintings relied heavily on earth-based reds and browns to depict human figures and interior scenes. These pigments also played roles beyond painting—used in cosmetics, religious rituals, and body adornment—across both the Mediterranean and regions of South America. While many pigments were locally sourced, trade in earth pigments, particularly high-quality ochres, has been documented throughout the ancient world.

During the Medieval and Renaissance periods, earth pigments formed the core of the artistic palette. Siennas, umbers and green earths were favored for rendering flesh tones, shadows, and underpaintings in panel and manuscript painting. Red ochres, provided a stable and affordable alternative to more expensive pigments such as vermilion or cinnabar. Their lightfastness, non-toxicity, and versatility made them indispensable in fresco, tempera, and early oil techniques.

In the Early Modern period and throughout the Industrial Age (17th–19th centuries), earth pigments remained widely used, though increasingly refined and commercialized. Companies such as Winsor & Newton and Kremer Pigmente began cataloging and distributing standardized earth pigments to professional artists. As academic painting flourished, earth pigments were commonly employed for imprimatura layers or tonal grounds. Even with the rise of synthetic pigments in the 19th century, natural earth pigments retained their appeal, thanks to their compatibility with traditional binders and enduring historical presence. Today, earth pigments continue to be valued in both contemporary art and heritage conservation. Artists seeking sustainable, non-toxic alternatives frequently incorporate them into natural palettes. In conservation, their mineral stability and availability make them ideal for retouching. Additionally, renewed interest in indigenous, vernacular, and community-based practices has brought further attention to the cultural relevance of naturally sourced earth pigments in both historical and living traditions.

Earth pigments in the INFRA-ART Database

The INFRA-ART Spectral Library contains a curated collection of natural earth pigments that currently comprises around 100 samples. These earth pigments span a wide range of hues and geological origins—from iron-rich ochres of Andalusia, green earths from Cyprus, and umbers from Germany and Italy, to unique deposits from Morocco’s Midelt region and volcanic earths near Iceland’s Snæfellsjökull. Sourced from diverse geological settings, these pigments exhibit variations in origin, mineral composition, and preparation methods, including fired variants such as burnt sienna and burnt umber. Their complex chemistry often involves mixtures of chromophore minerals (iron and manganese oxides/hydroxides) with accessory phases. Such compositions, together with distinctive geochemical fingerprints, make them valuable for provenance studies. Most samples have been analyzed via ATR-FTIR and XRF, with Raman and SWIR reflectance datasets currently in preparation. The database is periodically updated, with new samples added to expand its pigment diversity and analytical coverage.

Red Ochres

Sample name	Provenance	Sample ID	Pigment supplier	Spectral data
Red Ochre from Andalusia	Andalusia, Spain	PK11273	Kremer	FTIR, XRF, Raman
Red Ochre from Burgundy	Burgundy, France	PK11575	Kremer	FTIR, XRF, Raman
Red Ochre from Burgundy (dark)	Burgundy, France	PK11577	Kremer	FTIR, XRF
Red Ochre from Castille	Castille, Spain	PK11584	Kremer	FTIR, XRF, Raman
Red Ochre from Iceland	Snæfellsjökull, Iceland	PK11550	Kremer	FTIR, XRF, Raman
Red Moroccan Ochre (dark)	Midelt, Morocco	PK116440	Kremer	FTIR, XRF
Red Moroccan Ochre (fine)	Midelt, Morocco	PK116431	Kremer	FTIR, XRF, Raman
French Ochre RTFLES (washed)	France	PK40020	Kremer	FTIR, XRF
French Ochre SOFOROUGE	France	PK40090	Kremer	FTIR, XRF
Persian Red	Hormuz, Iran	PK17280	Kremer	FTIR, XRF
Red Bole	Germany	PK40503	Kremer	FTIR, XRF
Bole (ruby)	n/s	PK58270	Kremer	FTIR, XRF
Haematite (intense tinting)	n/s	PK48651	Kremer	FTIR, XRF

Red ochres samples and available spectral data

Yellow Ochres

Sample name	Provenance	Sample ID	Pigment supplier	Spectral data
Yellow Ochre (deep)	n/s	PK40301	Kremer	FTIR, XRF
Yellow Ochre from Andalusia	Andalusia, Spain	PK11272	Kremer	FTIR, XRF, Raman
Yellow Ochre from Burgundy	Burgundy, France	PK11573	Kremer	FTIR, XRF, Raman
Yellow Ochre from Iceland	Snæfellsjökull, Iceland	PK11551	Kremer	FTIR, XRF, Raman
Yellow Ochre (light)	n/s	PM132	Maimeri	FTIR, XRF
French Ochre (extra light)	France	PK40013	Kremer	FTIR, XRF
French Ochre JCLES (washed)	France	PK40040	Kremer	FTIR, XRF
French Ochre JFLES (washed)	France	PK40050	Kremer	FTIR, XRF
French Ochre JOLES (washed)	France	PK40030	Kremer	FTIR, XRF
French Ochre JTCLES (washed)	France	PK40010	Kremer	FTIR, XRF
French Ochre SAHARA	France	PK40130	Kremer	FTIR, XRF
French Ochre SOFODOR (golden)	France	PK40070	Kremer	FTIR, XRF
Satin Ochre, Monte Amiata (gold-orange)	Tuscany, Italy	PK40260	Kremer	FTIR, XRF, Raman
Taunus Ochre (light)	Hesse region, Germany	PK11540	Kremer	FTIR, XRF, Raman
Gold Ochre from Poland	Carpathian Mountains, Poland	PK40195	Kremer	FTIR, XRF, Raman
Gold Ochre from Germany	Saxony, Germany	PK11530	Kremer	FTIR, XRF, Raman
Gold Ochre	n/s	PSC18621	Schmincke	FTIR, XRF
Italian Gold Ochre (light)	Venice, Italy	PK40220	Kremer	FTIR, XRF, Raman, SWIR
Ochre Avana (greenish-yellow)	Italy	PK40200	Kremer	FTIR, XRF, Raman
Bole (yellow)	n/s	PK58275	Kremer	FTIR, XRF

Yellow ochres samples and available spectral data

Brown Ochres and Umbers

Sample name	Provenance	Sample ID	Pigment supplier	Spectral data
Brown Earth from Otranto	Otranto, Italy	PK11620	Kremer	FTIR, XRF, Raman
Brown Ochre from Andalusia	Andalusia, Spain	PK11276	Kremer	FTIR, XRF, Raman
Caledonian Brown	Morocco	PK40623	Kremer	FTIR, XRF, Raman
German Brown Ochre (light)	Germany	PK40231	Kremer	FTIR, XRF, Raman
Raw Umber from Cyprus	Cyprus	PK40610	Kremer	FTIR, XRF, Raman
Raw Umber from Cyprus (light)	Cyprus	PK40611	Kremer	FTIR, XRF
Raw Umber from Cyprus (slightly greenish)	Cyprus	PK40660	Kremer	FTIR, XRF
Raw Umber from Italy (greenish)	Italy	PK40612	Kremer	FTIR, XRF, Raman, SWIR
Fawn Ochre (very light umber, greenish)	Germany	PK40241	Kremer	FTIR, XRF, Raman

Brown ochres/umbers samples and available spectral data

Siennas

Sample name	Provenance	Sample ID	Pigment supplier	Spectral data
Raw Sienna, French	France	PK40392	Kremer	FTIR, XRF, Raman
Raw Sienna, Italian	Tuscany, Italy	PK40400	Kremer	FTIR, XRF, Raman, SWIR
Raw Sienna, Italian (brownish)	Tuscany, Italy	PK40410	Kremer	FTIR, XRF, Raman
Raw Sienna Badia, Italian	Badia, Italy	PK40404	Kremer	FTIR, XRF, Raman
Natural Sienna	Grosseto, Italy	PK17050	Kremer	FTIR, XRF
Raw Sienna Light	n/s	PM162	Maimeri	FTIR, XRF

Siennas samples and available spectral data

Burnt Siennas and Burnt Umbers

Sample name	Provenance	Sample ID	Pigment supplier	Spectral data
Italian Burnt Sienna	Italy	PK40430	Kremer	FTIR, XRF, Raman, SWIR
Burnt Sienna	n/s	PSE211	Sennelier	FTIR, XRF, Raman, SWIR
Burnt Umber	n/s	PM492	Maimeri	FTIR, XRF
Burnt Umber	Cyprus	PK40723	Kremer	FTIR, XRF
Burnt Umber (reddish-brown)	Cyprus	PK40730	Kremer	FTIR, XRF
Burnt Umber from Cyprus (brownish)	Cyprus	PK40710	Kremer	FTIR, XRF, Raman
Burnt Umber from Cyprus (dark brown)	Cyprus	PK40720	Kremer	FTIR, XRF
Burnt Green Earth (reddish)	n/s	PK40850	Kremer	FTIR, XRF
French Burnt Sienna	France	PK40470	Kremer	FTIR, XRF

Burnt siennas/umbers samples and available spectral data

Green Earths

Sample name	Provenance	Sample ID	Pigment supplier	Spectral data
Green Earth (yellowish)	Germany	PK40800	Kremer	FTIR, XRF
Green Earth from Cyprus	Cyprus	PK17400	Kremer	FTIR, XRF, Raman
Green Earth from Cyprus (bluish)	Cyprus	PK17410	Kremer	FTIR, XRF, Raman
Green Earth from Iceland	Snæfellsjökull, Iceland	PK11552	Kremer	FTIR, XRF, Raman
Russian Green Earth	Russia	PK11110	Kremer	FTIR, XRF, Raman
Russian Green Earth (extra fine)	Russia	PK11111	Kremer	FTIR, XRF
Bavarian Green Earth	Bavaria, Germany	PK11100	Kremer	FTIR, XRF, Raman
Verona Green Earth	Monte Baldo, Verona, Italy	PK11010	Kremer	FTIR, XRF, Raman
Bole (green)	n/s	PK58273	Kremer	FTIR, XRF

Green earth samples and available spectral data

Black and Violet Earths

Sample name	Provenance	Sample ID	Pigment supplier	Spectral data
Black Earth from Andalusia	Andalusia, Spain	PK11280	Kremer	FTIR, XRF, Raman
Bole (violet)	n/s	PK58272	Kremer	FTIR, XRF
Iron Glimmer Violet	n/s	PK48930	Kremer	FTIR, XRF
Iron Glimmer Violet (extra fine)	n/s	PK48933	Kremer	FTIR, XRF

Black and violet earth samples and available spectral data

Humic Earths

Sample name	Provenance	Sample ID	Pigment supplier	Spectral data
Van Dyck Brown	Germany	PK41050	Kremer	FTIR, XRF
Van Dyck Brown (dark)	Germany	PK41000	Kremer	FTIR, XRF

Humic earth samples and available spectral data

INFR-ART Blog

INFRA-ART spectral data collections: earth pigments

Nomenclature and terminology

Earth pigments in art: history of use

Earth pigments in the INFRA-ART Database

Further reading and resources

How to cite this resource