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Sinopia

Sinopia is a reddish-brown composed primarily of (Fe₂O₃), specifically , that was widely used from ancient times through the for creating preliminary underdrawings in wall paintings, particularly frescoes. The name derives from Sinope (modern ), a port city from which the finest quality of this pigment was mined and traded across the and worlds, often sealed in pellets to ensure authenticity. In fresco technique, sinopia was applied as a brush-drawn directly onto the rough arriccio layer of , serving as a guide for the final composition before the smoother intonaco layer was added and painted upon with wet pigments. This method, emerging prominently in the 13th and 14th centuries in , allowed artists to outline figures, architecture, and details in a rust-colored line that remained visible through the subsequent , facilitating precise execution of large-scale murals. While typically using red ochre mixed with water, rare examples, incorporating pigments like yellow ochre, green earth, , and , have been identified in ancient contexts, such as the 4th-century AD Lod Mosaic in , highlighting its versatility as a preparatory tool beyond standard es. The 's enduring legacy is evident in surviving sinopiae from sites like the Camposanto Monumentale in , where 14th-century underdrawings reveal the artistic planning of Gothic and masters, and its trade underscores the economic importance of natural earth colors in . By the , sinopia had largely been supplanted by other red ochres like , but the term persists to denote both the pigment and the underdrawing in .

Etymology and History

Origin of the Name

The term "sinopia" derives from the ancient Greek city of Sinope, located in on the coast (modern-day Sinop in ), which served as the primary export hub for this red earth in antiquity. The pigment was traded extensively from this port, leading to its nomenclature as a distinctive reddish ocher sourced from the region. The earliest recorded reference to the term appears in Pliny the Elder's (circa 77 CE), where he describes "sinopis" as a red earth first discovered in and named after Sinope, noting its superior quality compared to similar pigments from or the . Pliny highlights its use in painting for imparting warm tones, emphasizing Sinope's role in its commerce and distinguishing it from other earth-based colors. This ancient association established "sinopia" as synonymous with high-grade red ochers exported via the city's harbor. By the , the term evolved from denoting the itself—an iron oxide-based earth—to referring specifically to the preparatory underdrawings executed with it in techniques, particularly in Italian . Artists applied sinopia to the arriccio layer of to outline compositions before the final intonaco was added, a practice that emerged prominently in the 13th and 14th centuries, becoming widespread in Italian . This linguistic shift reflected the pigment's specialized role in artistic workflows during the period.

Historical Production and Use

Sinopia, a high-quality red ochre derived from deposits, was primarily produced through in the region of in central , with extraction occurring from caverns and open sites as described by ancient sources such as Dioscorides and . Archaeological evidence, including amphorae containing traces of the , indicates that and initial began in the Classical , with documented activity from the 6th to 5th centuries BCE, aligning with the establishment of Sinope as a key colony around the 7th century BCE. continued robustly through the Hellenistic and eras, peaking under administration, until exports largely ceased by the end of the CE due to shifting trade dynamics and improved overland routes via . The pigment's trade flourished along Mediterranean routes, facilitated by Sinope's strategic Black Sea port, which served as the primary export hub for shipments to , , and beyond. Strabo notes the pigment's high value, often sealed for quality assurance before transport in amphorae, with remnants found in sites like the Athenian Agora (6th–5th centuries BCE) and the Black Sea colony of (5th century BCE), underscoring its role in early maritime commerce. expansion further integrated sinopia into broader networks, with evidence from ancient ports and incidental finds suggesting regular voyages to Italian shores, where it supplemented local sources. Into the , production shifted to localized extraction in for Byzantine applications, maintaining continuity without the scale of ancient exports. Early adoption of sinopia-like red ochre appears in Egyptian art from the Predynastic period onward, where it was applied to pottery slips and mural paintings for symbolic red tones representing vitality and earth. In Etruscan contexts, 7th–3rd centuries BCE, the pigment featured prominently in tomb murals, providing durable reddish hues for figural scenes and architectural elements, as confirmed by pigment analyses from sites like . By the in , sinopia regained prominence through Venetian maritime imports, leveraging the republic's dominance in eastern to supply artists with the imported earth for underdrawings, ensuring its widespread availability across workshops from to .

Pigment Characteristics

Chemical Composition

Sinopia is classified as a natural earth pigment, primarily consisting of hematite (Fe_2O_3), a dehydrated form of iron(III) oxide that imparts its characteristic reddish hue. This core component typically constitutes 10–95% of the pigment, with the remainder comprising siliceous clays, silica (SiO_2), and accessory minerals. Compositional differences arise from geological origins, with deposits from the Sinope region in ancient Turkey renowned for their high iron oxide content, yielding a more vibrant and pure red-brown compared to other locales. In contemporary pigment nomenclature, natural sinopia falls under Pigment Red 102 (PR102), while synthetic versions mimicking its properties are designated PR101; both are iron oxide-based earth colors used in artistic applications. Historically, sinopia was extracted by mining ochre-bearing strata from natural outcrops, such as those near riverbanks or quarries, where iron-rich soils predominate. The raw material underwent grinding on stone slabs or mills to achieve a fine powder suitable for binding, followed by washing in water to eliminate impurities like sand, organic matter, and excess clays, thereby concentrating the for optimal pigmentation. This reddish-brown pigment's makeup made it ideal for preliminary sketches in techniques.

Physical Properties

Sinopia exhibits a color range from dark reddish-brown to brick red, depending on its content and processing, rendering it opaque when applied in thick layers while maintaining good tinting strength for achieving varied hues in mixtures. This opacity arises from its base derived from , allowing it to cover surfaces effectively without excessive transparency. In its typical form as a fine , sinopia possesses low , facilitating easy grinding and mixing with or binders to form smooth suspensions suitable for artistic preparation. Its texture supports uniform application, with the powder's fineness contributing to consistent handling properties across media. Sinopia demonstrates high permanence, with a lightfastness rating of 8/8 on the ASTM scale, making it resistant to fading under dry conditions and suitable for long-term use. However, it may undergo color alteration in the presence of if not properly bound, and its ranges from 4.5 to 5.0 g/cm³, reflecting its compact structure.

Artistic Applications

Preparatory Drawings in Frescoes

In the traditional process, sinopia functions as the essential underdrawing applied to the arriccio, the coarse initial layer of lime-based that prepares the wall surface. s typically begin with loose sketches to outline the composition's major forms, then refine these lines using a loaded with sinopia to create bold, visible contours for anatomical structures, architectural elements, and spatial divisions. This preparatory stage occurs before the intonaco—the fine, smooth finishing —is applied, allowing the to approve the with patrons and make corrections while the wall remains dry and stable. Design transfer to the arriccio relies on either direct freehand or methods involving full-scale preparatory cartoons. For precision in large-scale works, cartoons—paper sheets with pricked outlines—are positioned against the wall and pounced with a cloth bag filled with dust or powdered , producing a dotted guideline that is then strengthened with sinopia strokes for durability and clarity. During fresco execution, sections of intonaco are applied daily in manageable areas called giornate; the sinopia lines, being reddish, show through the thin, semi-translucent wet , serving as a subtle reference to ensure accurate pigment placement before the surface dries and fixes the colors irreversibly. Prominent historical instances underscore sinopia's workflow in major fresco cycles. In Giotto's Scrovegni Chapel (c. 1305), sinopia underdrawings were uncovered during the 1957–1963 restoration directed by Leonetto Tintori, revealing traces such as the Virgin's foot and robe folds in scenes like the Announcement of Mary's Death, which guided the painter's layered application of colors. Likewise, 1980s Vatican restoration analyses exposed sinopia underdrawings beneath Michelangelo's Sistine Chapel frescoes, including outlines for the Last Judgment (1536–1541) on the altar wall, illustrating how the pigment facilitated the execution of intricate figural groups amid the ceiling and wall ensemble completed between 1508 and 1512.

Use in Flesh Tones and Mixtures

In painting, sinopia was frequently blended with white pigments like lime white (bianco sangiovanni) or to produce subtle pink hues essential for rendering skin. , in his 15th-century manual Il Libro dell'Arte, prescribed mixing light sinopia with lime white in a 2:1 ratio to create cinabrese, a light red variant formed into small cakes for use in wall painting, particularly for flesh tones that required transparency and warmth. This mixture, often in proportions approximating half an ounce of with bean-sized amounts of sinopia and , yielded a delicate flesh-colored tint suitable for detailed application on or panels. To achieve greater realism in skin depiction, especially in portraits, sinopia was layered over verdaccio, a greenish-gray underpainting made from black, dark ochre, and white. Cennini outlined the process: flesh areas were first contoured with sinopia, followed by verdaccio for shading and shadows using terra verde, then built up in three gradations of sinopia mixed with white, applied softly to blend seamlessly and retain subtle verdaccio undertones for depth. This layering enhanced the three-dimensional quality of skin, with sinopia providing rosy highlights while the green base neutralized warmer tones for natural variation. In and techniques, sinopia mixtures were added post-fresco to refine flesh details, as the pigment's composition allowed for stable, warm overpainting without cracking. Cennini advised tempering sinopia with egg yolk for panel work, applying it in thin, gradated layers over verdaccio to model faces, hands, and figures, often combining it with cinabrese or black for rosy tints (rosatte) in highlights and . These methods contributed to the evolution from medieval icons' flat, uniform flesh rendering—relying on basic sinopia-white blends—to , where Cennini's recipes emphasized tonal modulation for lifelike subtlety.

Cinabrese

Cinabrese is an obsolete term for a pinkish pigment created by mixing sinopia or a similar red earth with white pigments such as or . This composite color, prominent in 15th- and 16th-century painting, particularly in , served as a cheaper and non-toxic alternative to derived from , which contains hazardous mercury. The name derives from "cinnabar" (cinabro in ), reflecting its intent to imitate the vivid red of the while using abundant, safer earth-based materials. Recipes for cinabrese appear in key treatises, including Giorgio Vasari's Lives of the Most Excellent Painters, Sculptors, and Architects (1550), where it is described alongside other earth pigments for and work. Earlier, Cennino Cennini's Il Libro dell'Arte (c. 1400) details preparing light cinabrese by combining sinopia with lime white to form small cakes, emphasizing its suitability for delicate applications in . These mixtures avoided the expense and health risks of true , making cinabrese accessible for widespread use in workshops. In artistic practice, cinabrese was commonly used for flesh tones, providing softer, skin-like hues through dilution with whites, and retaining the stability of red earth in techniques.

Venetian Red and Variants

represents a processed variant of the sinopia pigment, achieved by calcining natural red ochre—primarily composed of (, Fe₂O₃)—at temperatures ranging from 500 to 800°C to yield a brighter tone classified under (PR101). This thermal treatment dehydrates the iron hydroxides, enhancing and producing a more intense, permanent reddish-brown hue compared to unprocessed sinopia. From the onward, was traded extensively through , which controlled the processing and distribution of high-quality sinopia-derived pigments across , leveraging its position as a major port for eastern imports. This dominance in refining and exporting the pigment persisted until the , when synthetic alternatives began to supplant natural variants through industrial production methods. Other notable variants include English red, produced by calcining iron sulfate to create a purer, more vibrant form, and Indian red, derived from similar controlled firing of ochres sourced or processed in the for heightened color intensity. These differ from base sinopia primarily in their refined processing, which minimizes impurities and amplifies the shared foundation for superior saturation.

Modern Relevance

Conservation and Analysis

Modern conservation efforts for sinopia underdrawings emphasize non-invasive techniques to reveal and study these layers beneath fresco surfaces without causing further damage. Infrared reflectography (IRR), utilizing near-infrared (NIR) wavelengths, penetrates overlying plaster and pigment layers to visualize sinopia lines, leveraging the pigment's iron oxide composition for clear detection. This method has been instrumental in analyzing complex stratigraphies in wall paintings, distinguishing sinopia from other underdrawing materials like charcoal. Sinopia underdrawings face significant degradation risks from environmental factors, including plaster cracks that allow ingress and fluctuations that promote and powdering of the friable arriccio layer. These issues exacerbate loss of detail over time, particularly in historic structures exposed to cycles of wetting and drying. interventions often involve consolidants such as , an acrylic copolymer applied in dilute solutions (typically 3-5%) to stabilize flaking and bind particles without altering appearance, as demonstrated in treatments of detached wall fragments. This approach ensures reversibility and long-term while mitigating further mechanical from vibrations or settling. Beyond technical preservation, sinopia underdrawings hold substantial art historical value as autonomous artistic expressions, offering insights into artists' preliminary compositions, corrections, and stylistic evolution independent of the final . Since the late 1970s and 1980s, detached sinopias have been recognized and exhibited as standalone works in dedicated museum spaces, such as the Sinopie Museum in (opened 1979) and collections at the Uffizi Gallery in , underscoring their role in understanding preparatory practices. Hematite's chemical stability in sinopia further facilitates such analyses by maintaining visibility under diagnostic imaging.

Contemporary Replication

In the , synthetic pigments, designated as Pigment Red 101 (PR101), emerged as reliable mimics of natural sinopia, providing enhanced consistency, purity, and compared to variable natural sources. These synthetic alternatives, often produced through processes, replicate the reddish hue derived from while avoiding impurities common in mined earths; their commercial availability expanded significantly from the onward, facilitating broader artistic and industrial applications. Despite the prevalence of synthetics, natural sinopia extraction persists in select regions, notably 's Roussillon area, where ochre quarries in Apt continue to yield high-quality red earth pigments through traditional mining and processing methods, including pulverization and baking. These operations, managed by entities like Société des Ocres de France, supply authentic materials prized for their historical fidelity and non-toxic properties. For restoration projects, the International Centre for the Study of the Preservation and Restoration of Cultural Property (ICCROM) provides guidelines emphasizing the replication of original hues using compatible, reversible materials to ensure long-term preservation of frescoes and murals. These protocols advocate spectroscopic analysis and trial mixtures to match sinopia tones, prioritizing inert iron-based pigments that integrate seamlessly without altering substrate chemistry. Contemporary applications of sinopia extend to educational fresco workshops, where it serves as a foundational underdrawing medium on arriccio plaster, and to modern murals emulating techniques. Suppliers such as Kremer Pigmente offer authenticated natural red variants, like or Moroccan sources, ground to fine particles for use in , lime , and acrylic media, supporting both pedagogical programs and new artistic commissions.

References

  1. [1]
    Sinopia - MFA Cameo - Museum of Fine Arts Boston
    May 31, 2022 · It was used as a pigment from ancient times until the Renaissance. Sinopia was primarily used for sketches and underdrawings.Missing: definition | Show results with:definition
  2. [2]
    Gems on Canvas: Pigments Historically Sourced from Gem Materials
    ... chemical formula of Fe2O3. Its height of popularity as a gem was likely in ... All pigments pictured in this article are from Sinopia Pigments.
  3. [3]
    Roman commerce in pigments | Resource - RSC Education
    The colour became known as Sealed Sinop, and later the Latin and Italian name sinopia was given to wide range of dark red ochre pigments. Evidence of this trade ...
  4. [4]
    Techniques | Parnassus | Raphael - Projects
    Sinopia: Underdrawings for fresco paintings made with the red earth pigment sinopia, which is brushed on the arriccio layer and over which the intonaco is ...
  5. [5]
    Sinopia painting - museobenozzogozzoli.it
    To create a fresco, the painter began by coating the wall with a layer of plaster, which was made by mixing water with slaked lime, and large-grained river sand ...Missing: underdrawing | Show results with:underdrawing
  6. [6]
    The Pisa sinopites. what they are, what they were used for, how they ...
    Jun 22, 2024 · It was used in a compound made simply with this pigment and water: the rust-colored result was used to draw detailed sketches of the final work ...
  7. [7]
    Pliny, Natural History, 35 (a) - ATTALUS
    L [31] Sinopis was first discovered in Pontus, and hence takes its name from the city of Sinope. ... There are three kinds of Sinopis, the red, the faintly red ...Missing: exact quote
  8. [8]
  9. [9]
    [PDF] Anticipating Artistic Behavior: New Research Tools for Art Historians
    Prior to the 15th century, Italian artists drew with a brush a preliminary underdrawing. (known as sinopia, named after the red-earth pigment sinoper normally ...
  10. [10]
    [PDF] From the Miltos / Sinopis of Ancient Sinope to the Yoşa of Modern ...
    What was known in antiquity as the miltos of Sinope or as the Pontic sinopis referenced precisely the pigment extracted from the mines of Cappadocia. In late an ...
  11. [11]
    Colours of Ancient Egypt – Red | UCL Researchers in Museums
    Dec 4, 2018 · Red was an easy colour to obtain in ancient Egypt as naturally red minerals, or clays, were abundant. In fact, they were already used as pigments for painting ...Missing: sinopia | Show results with:sinopia
  12. [12]
    Analysis of Pigments in Etruscan Tombs in Sorano, Italy Using the ...
    The results of the measurements in the Etruscan tombs in Sorano showed that consist of the following pigments: yellow ochre, red ochre, calcite and carbon black ...Missing: sinopia | Show results with:sinopia
  13. [13]
    Inpainting: Pigments - MediaWiki
    Sep 3, 2021 · (Iron oxide 10–95% + silica and clay. Red ochre, caput mortuum, sinopia, Spanish red, Pozzuoli red). opaque, but high tinting glazes. Iron ...
  14. [14]
    The Color of Art Pigment Database: Pigment Red, PR - Art Is Creation
    *** Oil paints and watercolors using PR101 and PR102 exist in almost any shade of yellow-orange, orange, red, violet brown to green brown. PR102. Natural Red ...Historic Red Pigments Without... · CI Pigment Red · CI Common or Historical Name
  15. [15]
    What Is Ochre?: Earth Pigments Explained
    ### Summary of Sinopia Section
  16. [16]
    Pigments from the Earth: Part 1
    ### Summary of Extraction and Processing of Natural Earth Pigments
  17. [17]
    Implementation of Red Ochre in Sinopia: Non-invasive ...
    During the Hellenistic period, typical sinopia was based on red ochre as a single pigment, however, sinopia can also be polychrome paintings (Cennini, 1859).
  18. [18]
    [PDF] The Pigment Compendium
    ... high iron content and is a very common member of the mica group, forming a ... sinopia (q.v.) and one of bianco sangiovanni and used in fresco and ...
  19. [19]
    [PDF] PIGMENT SPECIFIC GRAVITY_jpechart1 - Just Paint
    Each (single) pigment density is expressed relative to water (1.00) under the pigment name. The line under each pigment also indicates their relative weight.
  20. [20]
    colormaking attributes - Handprint
    Iron oxides can be any of several colors, including earth yellow, earth orange, earth red, brown or black, depending on (1) the quantity of trace manganese, ...
  21. [21]
    Techniques | Jurisprudence | Raphael - Projects
    Sinopia: Underdrawings for fresco paintings made with the red earth pigment sinopia, which is brushed on the arriccio layer and over which the intonaco is ...
  22. [22]
    The Story of Sinopia
    ### Summary of Sinopia in Frescoes
  23. [23]
    How to paint a fresco (the Renaissance way) - ArtTrav
    Dec 28, 2008 · This part is called the sinopia, an underlayer of the fresco that can sometimes be uncovered through restoration – you may see this sinopia ...
  24. [24]
    [PDF] The restoration of Giotto's Wall Paintings in the Scrovegni Chapel of ...
    Indeed, in this case, removal of the stuccoing revealed the presence of sinopia, albeit only tiny traces near the edge. A few elements demonstrate that ...
  25. [25]
    HALT URGED IN WORK ON SISTINE AND 'LAST SUPPER'
    Mar 6, 1987 · As debate intensifies over restoration of Michelangelo's Sistine Chapel ... '' He had also seen some sinopia, or underdrawings, for the ...
  26. [26]
    [PDF] The Conservation of Wall Paintings - Getty Museum
    Although the fragmentary character and deteriorated condition of the right-hand sinopia precludes defini- tive identification of all the figures, it appears ...<|control11|><|separator|>
  27. [27]
    [PDF] The book of the art of Cennino Cennini
    egg is to be used to mix the colours. Didron trans- lates the Greek word by ... “'sinopia is used both for painting with the brush and for colouring ...
  28. [28]
    Cinabrese - MFA Cameo
    Description. An obsolete name for a pink pigment prepared as a mixture of red earth (sinopia, Venetian red, etc.) and white (chalk, lime white, etc.).Missing: drapery lips<|control11|><|separator|>
  29. [29]
    [PDF] Cinabrese - Kremer Pigmente
    Cinabrese is a skin color in early Renaissance painting, typically a mixture of Sinope (red earth) and Bianco San Genovese, suitable for watercolor and tempera.Missing: Vasari | Show results with:Vasari
  30. [30]
    The Project Gutenberg eBook of Lives of the most Eminent Painters ...
    ... cinabrese, and certain vitreous greens. Since then there have been also ... Giorgio Vasari, see Vasari; Giorgione da Castelfranco, xxxii; Giottino ...
  31. [31]
    Renaissance Pigments - Adobe Express
    Light Cinabrese- a light red (as far as Cennini knew, not used outside of Florence). Perfect for doing flesh. Mix sinoper with White Lime and make little cakes ...
  32. [32]
    Pigments through the Ages - Overview - Red Ochre - Webexhibits
    Used from prehistory and throughout history, these permanent pigments can be safely mixed with other pigments. Ochres vary widely in transparency; some are ...
  33. [33]
    Venetian Red: the Pigment that Evokes the Italian Renaissance
    Aug 31, 2022 · Red earth pigments were mixed with white as a basis for caucasian skin (a colour known as cinabrese), mixed with Yellow Ochre to depict glowing ...
  34. [34]
  35. [35]
    Venetian red - CAMEO
    Jun 25, 2022 · A permanent, reddish brown pigment. Venetian red was originally prepared from a natural Red ocher. By the 18th century, Venetian red was being manufactured by ...
  36. [36]
    [PDF] Archaeometric investigations on red pigments - I.R.I.S.
    - Metallogenetic: mainly hematite, in big lamellar crystals (micro or nano-metric) as a mineralization in ancient massifs, which gives extremely pure red ochre.
  37. [37]
    Revealing Underdrawings in Wall Paintings of Complex Stratigraphy ...
    Nov 24, 2021 · NIR imaging proved particularly useful in revealing both characteristic traditional fresco underdrawing materials (charcoal and sinopia) under ...
  38. [38]
    Sinopie Museum - Opera della Primaziale Pisana
    The sinopias housed in this museum are thus the preparatory drawings for the vast frescoes that adorned the walls of the Camposanto. Here we can admire and ...Missing: conservation infrared reflectography UV imaging
  39. [39]
    Marginal Notes on 'The Great Age of Fresco' - jstor
    This has led many to forget that sinopie were preparatory drawings, and to approach them as original, independent works of art.2 For the historian, however, the ...<|control11|><|separator|>
  40. [40]
    Pigment Stories: Earth Pigments and Their Synthetic Alternatives
    Mar 2, 2021 · Synthetic iron oxide pigments, also known as Mars pigments, were first created in the 18th Century, but they began to gain popularity as ...
  41. [41]
  42. [42]
    The Ochre Earth of Roussillon - theloadedtrunk.com
    Roussillon's ochre earth is a geologic phenomenon with russet red, mustard, and apricot hues, and is the world capital of ochre. It was used for non-toxic dye ...
  43. [43]
    [PDF] ARC Laboratory Handbook - ICCROM
    The ICCROM ARC Laboratory Handbook is intended to assist professionals working in the field of conservation and restoration of architectural heritage. Target ...
  44. [44]
    Spanish Red Ochre Pigments | Kremer Pigments Inc. Online Shop
    A special mixture of natural occurring minerals produces this orange-red ochre which we supply in two grinds. 11584 is suitable for underpainting and full tone ...Missing: sinopia | Show results with:sinopia
  45. [45]
    Mariani Affreschi Academy | Scuola di pittura ad affresco
    Jan 11, 2017 · Choosing of the preparatory drawing and transfer onto the support: this stage can be performed in various ways, such as sinopia (full-scale ...