Zaffre (zaffer) is a vibrant deep blue pigment developed by alchemists, major pigment creators, by c. 1550 AD. Characterized by brilliant hues and unique composition, zaffre is beloved in the Renaissance, Baroque and Victorian Era in paint, glazes and glassmaking.
Zaffre gets its rich blue tones from metallic cobalt ores. The name is thought to originate from Italian zaffra, meaning the toxic metal cobalt. "Zaffer" is first recorded in English in the 1550s. Zaffre is a primary ingredient for producing smalt, beautiful cobalt blue glass.
Cobalt blue glass is known from ancient Egypt and Mesopotamia. This color in glass production grinds to a halt c. 1250 BCE at the advent of the Bronze Age collapse. For web colors, zaffre or zaffer is hex triplet #0014A8.
About Cobalt
Cobalt is a transition metal essential for creating this distinctive blue pigment. It's obtained from mineral ores cobaltite and smaltite (cobalt arsenide). Despite its quantitative hazards cobalt is essential for health in animals in minute amounts as a component of vitamin B12.
A chemical element, cobalt has symbol Co and atomic number 27. As with nickel, cobalt is found in the Earth's crust only in a chemically combined form, save for small deposits found in alloys of natural meteoric iron.
A deficiency of cobalt is very rare and potentially lethal, as it causes pernicious anemia. In this case not enough blood cells are produced due to lack of B12, and the person initially feels weak and lethargic, followed by nausea, chest pain, numbness and confusion.
Cobalt is named after a German mine spirit, the Kobold. Kobolds are also found in homes and on ships at sea, where they can be helpful unless insulted.
The mine kobold is more malevolent or mischievous, corrupting good metal and giving nothing back. In 18th century German copper mines he's called Nickel (Little Nick), after whom that metal is named.
How is Zaffre Made?
Production of zaffre involves roasting cobalt ore, resulting in either an impure form of cobalt oxide (CoO) or impure cobalt arsenate (CoAsO4). The complexity of its creation lies in the extraction and purification processes of cobalt.
Roasting Cobalt Ore
The ore is heated to high temperatures in a furnace, to convert the cobalt within it to cobalt oxide. This is a volatile form, separated from other minerals and impurities.
The temperature to roast cobalt ore usually exceeds 1200 °C (2192 °F). Maintaining this temperature ensures a uniform product.
Obtaining the Pigment
The resulting product is then cooled and ground to form a powder yielding the vibrant blue hue characteristic to zaffre. It contains cobalt and impurities can affect both color and quality. Methods of producing zaffre evolve over time.
What is Cobalt Oxide?
Cobalt oxide, a compound of cobalt, exists in two main forms: CoO (cobalt(II) oxide) and Co3O4 (cobalt(II,III) oxide). The simpler CoO is essential for making blue pigments. Besides vivid color, cobalt oxides are durable and heat resistant for use in ceramics and glass.
The stability and chemical properties of cobalt oxide are ideal for artists seeking a reliable blue pigment. Cobalt blue is often preferred over other shades due to its vibrant saturation. It will fade over time but with newly developed pigments lightfastness is hard to judge.
What is Cobalt Arsenate?
Cobalt arsenate comes from combination of cobalt oxide and arsenic acid. Characterized by a greenish-blue color, cobalt arsenate is historically used to manufacture diverse dyes and pigments including zaffre, and is highly toxic.
Historically, cobalt arsenate is used to create various blue shades for glass and ceramics. Although arsenic compounds produce some of the most vibrant colors, including King's Yellow (orpiment) and Scheele's green, exposure to arsenic leads to serious health issues.
“Of the many painters I have known, almost all I found unhealthy … If we search for the cause of the cachectic and colorless appearance of the painters, as well as the melancholy feelings that they are so often victims of, we should look no further than the harmful nature of the pigments…”
~ I8th century doctor Bernardinus Ramazzini
Smalt: The Allure of Cobalt Blue Glass
Smalt is a cobalt blue glass first produced in the late 15th century. The earliest known methods involve mixing finely powdered cobalt oxide with glass particles and melting them together in a furnace.
Potassium carbonate is incorporated into the glass as a flux to enhance its flow. Potassium also helps bolster the blue. After being thoroughly mixed, the heated glass is introduced to water, where the sudden temperature shock causes it to shatter into small fragments.
These are ground into coarse pigment. The color must be carefully ground and only for a short time. The smaller the granules, the weaker the hue. Artists find it a cost-effective substitute to ultramarine, a pricey pigment made of the coveted blue stone lapis lazuli.
Smalt has widespread applications in decorative arts, pottery and stained glass windows. It continues to be appreciated today for its luminescent qualities without the harmful toxins.
Historical Uses of Zaffre
Zaffre enjoys widespread popularity throughout the centuries, culminating in a zaffer boom in the Victorian Era. Artists use its vibrant blue hue in everything from paintings to stained glass windows and ceramics. Its versatility makes zaffre desirable in artistry.
This pigment was especially favored for its ability to retain its hue when mixed with different mediums such as oils and watercolors.
Throughout history, zaffre has found its way into various applications:
Art and Paints: Artists utilized zaffre in oil paints and watercolor for its richness and lightfastness.
Stained Glass: Zaffre was a crucial ingredient in the production of stained glass, allowing for intricate designs that captured light and color in cathedrals and churches.
Ceramics: Potters used zaffre for glazing ceramics, enhancing both durability and aesthetic appeal.
Textiles: It produces vibrant blue dyes for textiles, contributing to the toxicity of historical fashion. Garments dyed with zaffre have been found in period pieces displayed in museums.
Hazards of Zaffre and Its Components
While zaffre and its components can create exquisite colors, both cobalt and arsenic are toxic materials. Prolonged exposure to cobalt can lead to health issues such as lung disease or skin ailments. Arsenic is a common poison associated with potentially lethal effects.
Facts about Zaffre
Historical Period: Zaffre gains prominence particularly from the late Renaissance to the Victorian Era.
Color Composition: The vibrant blue color of zaffre can be attributed to the properties of cobalt, which absorbs red light and reflects blue wavelengths.
Modern Applications: Even today, cobalt compounds continue to be used in glass, paint, and ceramics, albeit with more stringent safety regulations.
Cultural Impact: The alluring blue pigment of zaffre has fascinated artists, decorators, and historians alike, leaving an indelible mark on numerous artistic traditions.
Non-Fiction Books:
Fiction Books:
READ: Lora Ley Adventures - Germanic Mythology Fiction Series
READ: Reiker For Hire - Victorian Detective Murder Mysteries