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Notes on the colour blue

Updated: May 2, 2023

with photography historian Elisabeth Scheder-Bieschin

I’ve been making cyanotypes for a few years now. I love the simplicity of the cyanotype process and connection to nature through the light of the sun. But most of all I am enchanted by the colour blue. I’m not the only one who is captivated by blue. According to various surveys most people in the world state that blue is their favourite colour. Blue is the colour of the sky and the ocean, of space, eternity and of light. Blue is associated with calm, tranquillity and peace but also with sadness and despair. Blue is special. Much of our world is blue – the sky as well as the sea appear blue to our eyes. The sky appears blue to our eyes because the many tiny molecules and larger particles in the air scatter the lights of different wavelengths by different amounts. The scattering caused by these tiny air molecules (Rayleigh scattering) increases as the wavelength of light decreases. Violet and blue light have the shortest wavelengths and red light has the longest. Therefore, blue light is scattered more that red light and the sky appears blue during the day.

Ultra-marine pigment

Artists have tried to capture the blue of the sky and the ocean since the beginning of time. But in ancient art like the cave drawings there is no

blue. Making blue pigments was very complicated. Until the renaissance blue wasn’t widely used. It turned out that to achieve the most stunning blue one needed to crush the semi-precious stone Lapis Lazuli found in Afghanistan into a fine powder and mix it with a binding agent like egg yolk or oil. This special blue was called ultra-marine which translates as ‘from beyond the sea’.

The complicated production process resulted in very high prices. At times blue pigment was even more expensive than gold. Ultra-marine was used sparingly and reserved for subjects such as the Virgin Mary. Blue became the most sacred colour in Christian iconography. Painters like Botticelli, Raphael or Titian liked using ultra-marine blue in their paintings.

The blue robes of the Virgin Mary by Masaccio were painted with ultramarine. (1426)


There were other blue paint colours besides ultramarine. One colour that

was hugely popular in the 16th and 17th century was the Indigo, an

ancient paint and dye that was derived from plants growing in India.

Inigo was traded along the silk route from India and Egypt to Europe.

Prussian blue

In the early 18th century, a German chemist discovered Prussian blue.

This was produced by oxidation of ferrous ferrocyanide salts. Prussian

blue was one of the first modern synthetic and inorganic pigments.

Prussian blue was much cheaper and easier to produce than


Katsushika Hokusai, Under the wave off Kanagawa, also known as The Great Wave. Woodblock print. C. 1830

‘Feeling blue’ is an expression which might come from a century old

tradition of ships flying blue flags when a captain or another officer had

died. Another explanation of the origin of "feeling the blues"; is a tradition

used by many West African cultures for mourners to wear garments dyed

indigo blue to indicate suffering. Picasso used many shades of blue in his

paintings during his ‘blue period’ but mainly Prussian blue. The

melancholic feel to Picasso’s paintings from his ‘blue period’ contributed

to the associations of sadness and despair with the colour blue.


International Klein Blue (IKB) looks very similar to ultra-marine – it was

mixed by and named after the conceptual artist Yves Klein. He wanted

to paint the sky. For Klein, the colour blue was intrinsic to his aesthetic

philosophy: "blue is the invisible becoming visible. Blue has no

dimensions; it is beyond the dimensions of which other colours partake."

He painted hundreds of blue paintings.

Portrait of Yves Klein during the shooting the documentary of Peter Morley "The Heartbeat of France". Studio of Charles Wilp, Dusseldorf, Germany, February 1961. Copyright Charles Wilp / BPK, Berlin.

Blue photography

Some of the earliest photographs were blue. In 1842 Sir John Herschel discovered the cyanotype process by using a solution of ferric ammonium citrate and potassium ferricyanide. These iron salts are

reduced to their ferrous state when exposed to UV light and produce a Prussian blue image when oxidised. He was thrilled to have found a way of copying his notes on astronomy through a blueprint. But the daughter of a friend, Anna Atkins, combined the knowledge of the science with the idea of photography and began making her now famous books of botanical specimen, starting with British algae.

Anna Atkins

Try your hand a cyanotype:

Cyanotypes are fun and easy to do. The chemicals are not very expensive, nor are they toxic like so many other chemicals used in analogue photography. You can either buy the chemicals and you’re your own paper or you can buy cyanotype kits which have everything

you need to make your own cyanotype.

Why don’t you start with photograms like Anna Atkins did in the 1840s? Our online course at Alternative Processes Academy teaches you the basics of cyanotype as well as printing on unusual surfaces like shells, teabags, marble, glass and more! Launch price until May 10th.

Author: Elisabeth Scheder-Bieschin

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