How printing conquered the rainbow

Iris was goddess of the rainbow and messenger of the other gods of ancient Greece. She was also the most elusive divinity. She appeared, traced her bow through the sky, then suddenly fled, as Roman poet Ovid tells us. Colors fill us with bliss, but they have been hard to seize for centuries. Maybe the wish to grasp the rainbow is what pushed humanity to tame color. It has been a long, arduous enterprise. But we have finally learnt the trick: how to trap colors in paper, tissue and objects, and distribute them to millions of people. What follows is the story of how the printers conquered the rainbow.

“Penny plain, twopence colored”

English children in the early 1800s wishing to buy paper actors for their toy theatres found this offer: “penny plain, twopence colored”. The printed sheets filled with characters had to be hand-painted, which doubled the price. Printing techniques had existed for a couple thousand years by then, but were mostly monochromatic. Color was hard to print on multiple copies, it was still easier to lay it on by hand. This was the case for the holy cards of gods and saints, reputed to be the first widespread printed objects. Pages in red and black characters where among the most colorful things that could be churned out by a printing press, invented by Johannes Gutenberg in the 15th century. Later on, artists experimented with techniques like chiaroscuro or mezzotint, to try and give life to their printed images. But these techniques were slow and expensive.

Ink thirst

By the 19th century, the world was thirsty for color. Natural history, archaeology and exploration had made giant steps. Readers were eager to see publications with colorful pictures of the latest findings and maps. It was also the era of Romanticism, which made the Middle Ages trendy again: readers were disappointed when comparing their dully printed books with the illuminated medieval manuscripts.

But colored inks were both harder to make and more expensive than black. In 1852, while drawing the map of English counties, mathematician Francis Guthrie formulated the map coloring problem: what was the smallest number of colors necessary to avoid that bordering counties had the same color? This proved to be no small challenge, since it was not until 1976 that the answer was mathematically confirmed: four.

Iris’ four veils

The answer to the thirst for color had been there for two centuries, without anybody noticing. In the 17th century, the science giant Isaac Newton had discovered that all colors resulted from the combination of three: green, red and blue – the primary colors. The colors of a printed image are actually light reflected by that same image, but the primary colors discovered by Newton are related to the behavior of direct light: in the case of reflected light, however, the optical laws are different. But in the 17th century the German painter Jacob Christoph Le Blon started to play with Newton’s old idea. He was the first to produce color print images by superimposing successive layers of colors (he used yellow, red and blue).

This technique would evolve into the famous four color system, still used today, with magenta, cyan, yellow and black to add emphasis. It may sound easy, but it poses at least two major challenges. First, color separation: the image has to be divided into different layers, which was done by eye until the end of the 19th century. Second, registration: the different colors have to be placed on the paper in the right spot, a very difficult task at a time when printing used damped paper, which expanded with humidity.

The color boom

The rainbow revolution took off when the four-color system joined with the standard printing technique of lithography. In 1796, the German inventor Aloys Senefelder noted to his surprise that a piece of Bavarian stone he had used as an inking slab absorbed ink when dry, but refused it when wet. This discovery became the basis for using those stones as stamps to print on paper. In 1837, the French printer Godefroy Engelmann went a step further by painting stones with different inks and pressing them successively on paper to obtain colorful images: chromolithography was born. Large stones could be used to make many color printed copies of popular paintings as well as greeting cards, valentines, postcards and Sunday school texts. Before long, color print became a part of daily life.

No more grey walls

After the color boom, the streets of the main cities were transformed. In the second half of the 19th century, eye-catching posters for theatres, circuses and horse races enlivened the walls of cities like London and Paris. In the 1890s, artists led by Jules Chéret, Henri de Toulouse Lautrec and Théophile Steinlen created the golden age of the French poster. This was the beginning of an artistic expression that has evolved through such movements as Art Decó and Futurism through our own time, elevating the poster into a highly collectible art form.

More than paper

While Engelmann was devising chromolithography, a French engineer called Louis-Jerome Perrot found a way to obtain a similar success on textile. His machine for color printing on cloth, the “perrotine”, ended up impacting the global textile industry. In addition, printers managed to “trap the rainbow” not only on paper and cloth, but also on glass, leather, ceramic, metal, plastic and wood. All sorts of objects could be produced in vivid colors: playing cards, banknotes, postage stamps, wallpapers, envelopes and much more.

Mass production

By the beginning of the 20th century, color printing was ready to become a mass production industry. With the arrival of photography, the last manual aspects of the craft began to disappear. Before photography, artists and designers had to create images directly on the stone or metal surface used to print. After, they could draw on paper and photography would be used to transfer the image onto the printing surface. Moreover, photographic filters could be used to separate colors automatically.

A further breakthrough, offset printing, made it possible to transfer images onto cylinders, made of rubber or other materials, rather than rigid slabs or plates. This was the start of the rotary press, with its frantic spinning, capable of printing at high speeds on a wide range of papers. Full-color magazines, from Fortune to National Geographic, entered popular culture. Although daily newspapers remained black and white for much longer, in the interests of cost and efficiency, they eventually joined the world of color in the 1980s.

Marylins

The series of gaudy portraits of Marylin Monroe by Andy Warhol are the best representation of today’s color printing: massive series production of all kinds of splashy images. Although Warhol mainly used a printing technique akin to stenciling, his works reflect the technological advances of his time. The famous photocopying machine company Xerox has the name of a technique, xerography, that uses electrostatic fields to concentrate pigment particles in the desired areas, and fixes them through heat.

Since the 1980s, the eruption of information technology has made it possible to generate shapes and designs using computer software. Inkjet printers transform these electronic instructions into dots on paper, by directing tiny jets of ink from a nozzle in the manner of an airbrush. Laser printers project beams of laser light onto a cylinder, generating differences in electric charge that attract ink, which is later transferred from the cylinder to the paper.

Towards the future, back to the past.

The future of color printing takes us to places probably unimagined by its inventors, as it vaults from its classic bidimensional paper space to that of color 3D printers. But at the same time, more and more workshops are popping up that maintain old printing machines to use in fine art projects. Why is that? “Printing […] is now just one of several means of delivering the same electronically stored messages”, wrote the godfather of printing scholars, Michael Twyman, in 1998. That’s even more true in our time of mobiles and tablets. But he also pointed out that everything suggested that society would not stop printing. “The tangibility and portability of printed matter are characteristics that we have come to value highly”, he said.

Learn more on the history of color printing here:

The British Library guide to printing: history and techniques, Michael Twyman
Printing 1770-1970 an illustrated history of its development and uses in England / Michael Twyman
How to identify prints: a complete guide to manual and mechanical processes from woodcut to ink jet / Bamber Gascoigne