Generative Design

Rune Madsen is an artist-cum-programmer who uses, as he puts it, “programming languages to create things with the computer” and believes in “simplicity, organized complexity, and that the pragmatic and poetic are inseparable”. Nice. Me too. I think.
Anyway, I’ve been very interested in the idea of generative design and art lately. The notion that the representation and repetition of form and shape can be generated by some kind of algorithm gets me going…
There are lots of examples in the fine arts: MC Escher, Sol Lewitt and Piet Mondrian all had this repetition of form in their work but more recently, people have been using code as a kind of art form in and of itself..
Here are some examples I’ve been working on myself using the p5 JavaScript libraries.
Rotating Cubes

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Filling in the Blanks: A Prehistory of the Adult Coloring Craze

Its dizzy heights may have passed, but the fad for adult coloring books is far from over. Many trace the origins of such publications to a wave of satirical colouring books published in the 1960s, but as Melissa N. Morris and Zach Carmichael explore, the existence of such books, and the urge to colour the printed image, goes back centuries.

Uncolored portraits of the artists involved in the production of Leonhart Fuchs’ De historia stirpium commentarii insignes — Source.
For many publishers around the world 2015 was, fiscally speaking, an excellent year — a welcome boost in an otherwise uncertain decade. But this upturn had a perhaps surprising source: coloring books for grown-ups. What strange winds conspired to suddenly urge adults in their droves to take up colored pencils again? Whatever the reasons, sales rocketed: Nielsen logged sales of 12 million for the category in 2015, up from a measly 1 million the year before. In February 2016, with the craze still going strong, New York Academy of Medicine Library gave birth to a new initiative called Color Our Collections Week, a scholarly take on the coloring trend. Now in its third year, the campaign sees, on the first week of February, archives, special collections, and libraries take to social media with individual images and even entire books compiled from their holdings for the public to color. While these chosen works are all in the public domain, and so can technically include (in the US at least) works published up until 1924, the images in these coloring books more typically hail from the fifteenth through eighteenth centuries. And it is in these images — published in the centuries prior to the advent of color printing — that we can see a precedent for this seemingly modern fad. While it may seem like simply jumping on the adult coloring bandwagon, Color Our Collections Week, with its naturally historical focus, is actually tapping into (and shedding light on) a tradition much older.
Last year, the New York Academy of Medicine Library chose an image from Leonhart Fuchs’ monumental 1542 botanical work, De historia stirpium commentarii insignes (“Notable Commentaries on the History of Plants”), to promote the event. An archivist from the History of Science Collections at the University of Oklahoma chimed in on Twitter to say their own copy of this book had already been colored in.

The page from the University of Oklahoma’s colored version of Leonhart Fuchs’ De historia stirpium commentarii insignes — Source

Another colored edition of Leonhart Fuchs’ De historia stirpium commentarii insignes — Source (Wellcome Library)
Should we be surprised by this? Color Our Collections Week might give the impression that these images, from the era before colored printing, are at last being colored — rescued from their hitherto drab monochrome existence. Yet printed images from the early modern period were regularly colored by hand.
The practice goes back to the earliest days of print in the fifteenth century. Artists, printers, booksellers, consumers, and readers all applied color to originally black-and-white images. Before Gutenberg’s innovation of the moveable-type press, both woodblock and engraved prints, single sheets with printed images, were popular in Germany and parts of Central Europe. They were used in various ways, and many people did what we might do with them — hung them on the walls of their home.
With the emergence of the printed book the coloring trend continued. Colored illustrations were common in medieval manuscript books, most notably in the intricately illuminated manuscripts produced by monastic institutions. The early printed books from the fifteenth century and after often imitated the textual design and illustrations of these medieval manuscript books. Indeed, illuminated manuscripts and printed books were not mutually exclusive: some printed books contain illumination, while some manuscripts have painted prints pasted into them. It would seem that at least some early printers and readers attempted to create color illustrations for these works the only way they knew how: by coloring the pictures themselves.

This 1493 herbal shows how early printed works imitated manuscripts — Source (Wellcome Library)
The images below further demonstrate this transition from medieval to early modern book production, and the role colored illustrations played. Both are from De Claris Mulieribus, a fourteenth-century book by Giovanni Boccaccio (author of the Decameron). This work was a compilation of biographies of women, real and mythical, famous and infamous. It was first circulated as a manuscript, and surviving examples are richly illustrated with images of the women they discuss. The book was among the first to make the leap from manuscript to print, and the illustrations came with it. In order to recreate the feel of previous versions of the work, it needed colored illustrations. The images below are, fittingly enough, of the painter and sculptor (and apparently prolific creator of self-portraits) Iaia of Cyzicus (also known as Marcia). The first two are from manuscript versions of the work, showing Marcia sculpting and painting.

Marcia sculpting, image from a 15-16th century version of Giovanni Boccaccio’s De claris mulieribus — Source.

Maria painting, detail of page from a 1403 version of Giovanni Boccaccio’s De claris mulieribus— Source.
These next two are from printed editions of the work. The Latin edition has some illumination of the letters, while the German book’s image is fully colored.

Image of Marcia, uncolored, from a 1473 Latin version of Giovanni Boccaccio’s De claris mulieribus — Source.
Image of Marcia, colored, from a ca. 1474 German version of Giovanni Boccaccio’s De claris mulieribus — Source.
Most illustrations found in books from the early days of print are in the form of woodcuts and etchings. Woodcuts were most compatible with moveable type because both used relief printing, and early printers could easily print a page with both text and illustrations.
Because of the carving and printing process, woodcuts have simpler designs with less shading. They therefore make for excellent coloring pages, and Color Our Collections participants frequently choose woodcuts for their images. Moreover, art historian Susan Dackerman argues that they were meant to be colored. Many of these color prints were created in a workshop setting, with an engraver, printer, and colorist working together. The “vast majority” of surviving fifteenth-century woodcuts are hand colored, and they were produced in the tens of thousands in the fifteenth century.1
Some images, like this fifteenth-century German woodcut of Christ on the cross, are only complete once colored. In this case, angels hold cups to catch blood that needs to be added with paint. The National Gallery of Art owns a number of examples of this woodcut, each differently colored. Some have been left uncolored, and a couple have only the requisite blood added to complete the image. Among those more fully colored, we can see that quite a bit of artistic license was taken.

Christ in Color (ca. 1490), more fully colored, with clouds and other details — Source
According to Dackerman, twentieth-century art historians and collectors denigrated color, seeing it as nothing more than a way to hide the flaws of poorly-executed engravings and woodcuts. Well-executed prints, they argued, needed no color at all. This disdain for colored prints helped to obscure their place in art history. This line of argument harkened back to the debates that emerged during the Italian Renaissance over whether design or color were most important (disegno/colore).
In many of these images, the paint seems hastily applied. This haphazard coloring was often a result of the artist having many prints to paint rather than a lack of skill. Artists applied paint freehand, using a brush, but they sometimes employed stencils made from extra impressions of the images in order to paint more quickly.
Many works were colored not by professionals, but by readers. A lot of the examples we have found of hand-colored illustrations come from botanical works and herbals. For example, a copy of John Gerard’s Herball (1636), with selective images colored in, suggests it was the reader who painted it, perhaps as a way to record plants he or she had seen in person. Botany and painting were favored pursuits of genteel men and women in this period, so it’s not surprising that the same people would share both hobbies.
While publishers may have informally expected these monochrome images to be colored by some readers, it wasn’t until the eighteenth century that the practice was formalised in the first purpose-made coloring books. And in these the link between botany and painting persisted. Robert Sayer’s The Florist, published in London in 1760, was one of the first books where the author explicitly intended readers to color in the images. Comprised of pictures of various flowers, the author gives his (presumably) adult readers detailed instructions for paint mixing and color choice (including the delightful sounding “gall-stone brown”).

Page from Robert Sayer’s The Florist (1760) — Source
Botanical works were particularly suitable for readers who wanted to engage directly with a physical book, because they offered images of things that could be observed in the natural world. Although the images in this particular copy of The Floristwere left uncolored, the owner used the book to press actual plants. Many botanical works were heavily annotated, sometimes by several different owners, and pressed plants are often found in their pages.
The Florist was produced “for the use & amusement of Gentlemen and Ladies”, but most subsequent coloring books were created with children in mind. By the nineteenth century, these books became increasingly popular. Although they helped children develop artistic skills, creativity was not particularly prized. In The Young Artist’s Coloring Guide, a series published in the 1850s, a fully-colored version accompanied the uncolored image, ostensibly to imitate.

Two pages from The Young Artist’s Coloring Guide. No. 12 (ca. 1850) — Source.
In Walter Crane’s Painting Book, originally published in 1880, there’s also color companions to copy, though one could argue in this case, they being from the hand of one of the nineteenth century’s greatest illustrators, such an approach made for a significantly more beautiful object and one likely enjoyed by adults as well as children.

Two pages from Walter Crane’s Painting Book (1889 edition) — Source.
Crane wasn’t the only noted illustrator of the time to lend his name to such a book. A year earlier came The “Little Folks” Painting Book, published by the McLoughlin Brothers, with illustrations by noted artist Kate Greenaway. With no accompanying colored example to copy it was a bit less didactic than Crane’s but it still cautioned children to use a “fitting choice of colours”, and there was a pre-colored frontispiece which would have acted as a guide of sorts to the color scheme.

Two different colourings of the same image in The “Little Folks” Painting Book (1879) — Source
Of course, in the case of these Victorian examples, and earlier offerings such as The Florist, the coloring-in is the very raison d’etre of the book. The early modern examples less so. Though that’s not to say a similar enjoyment was not taken by early modern readers wanting to colorize their wooducts or etchings, that same thrill of bringing color to what was once blank. It seems the therapeutic effects were not unnoticed at the time either. In his 1622 work The Compleat Gentleman Henry Peacham, in a chapter encouraging the practice of coloring-in printed maps, talks of how “the practise of the hand, doth speedily instruct the mind, and strongly confirme the memorie beyond any thing else.”2
As for the modern trend in adult coloring books, critics havecharged marker-wielding grown-ups with being childish, and have alleged that the success of these books is a product of a dumbed-down culture. It may indeed be a fad, but it also has a longer history. So, the next time you buy an adult coloring book or get excited about Color Our Collections Week, know that you are not being childish. Rather, you are taking part in a long tradition of printed images that were meant to be colored.
This article was originally published in The Public Domain Review under a Creative Commons Attribution-ShareAlike 3.0. If you wish to reuse it please see:
About the authors
Melissa N. Morris is an Assistant Professor of History at the University of Wyoming. She has a PhD in History from Columbia University, where she wrote a dissertation on how plants mediated relationships between Europeans and Indigenous peoples in the seventeenth century Americas. On Twitter here.
Zach Carmichael is Local History and Genealogy Specialist II at the Carnegie Library, Muncie, IN. He has an MA in history from Miami University (OH), where he studied colonial New England taverns, and an MLIS from the University of Pittsburgh, where he specialized in archives. On Twitter here. 
1. Susan Dackerman, Painted Prints: The Revelation of Color in Northern Renaissance and Baroque Engraving, Etchings, and Woodcuts (University Park, PA: The Pennsylvania State University Press, 2002), 10.↩2. Henry Peacham, Peacham’s Compleat gentleman, 1634., with an introduction by G.S. Gordon (Oxford: Clarendon Press, 1906), 65.↩

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The Red and Green Specialists: Why Human Colour Vision is so Odd

Most mammals rely on scent rather than sight. Look at a dog’s eyes, for example: they’re usually on the sides of its face, not close together and forward-facing like ours. Having eyes on the side is good for creating a broad field of vision, but bad for depth perception and accurately judging distances in front. Instead of having good vision, dogs, horses, mice, antelope – in fact, most mammals generally – have long damp snouts that they use to sniff things with. It is we humans, and apes and monkeys, who are different. And, as we will see, there is something particularly unusual about our vision that requires an explanation.

Over time, perhaps as primates came to occupy more diurnal niches with lots of light to see, we somehow evolved to be less reliant on smell and more reliant on vision. We lost our wet noses and snouts, our eyes moved to the front of our faces, and closer together, which improved our ability to judge distances (developing improved stereoscopy, or binocular vision). In addition, Old World monkeys and apes (called catarrhines) evolved trichromacy: red-, green- and blue-colour vision. Most other mammals have two different types of colour photoreceptors (cones) in their eyes, but the catarrhine ancestor experienced a gene duplication, which created three different genes for colour vision. Each of these now codes for a photoreceptor that can detect different wavelengths of light: one at short wavelengths (blue), one at medium wavelengths (green), and one at long wavelengths (red). And so the story goes our ancestors evolved forward-facing eyes and trichromatic colour vision. And we’ve never looked back.

Figure 1. The spectral sensitivities of the colour cones of a honeybee. Reproduced based on Osorio & Vorobyev, 2005

Figure 2. The spectral sensitivities of the colour sensors of a digital camera. Reproduced based on original data of the Author’s.

Colour vision works by capturing light at multiple different wavelengths, and then comparing between them to determine the wavelengths being reflected from an object (its colour). A blue colour will strongly stimulate a receptor at short wavelengths, and weakly stimulate a receptor at long wavelengths, while a red colour would do the opposite. By comparing between the relative stimulation of those shortwave (blue) and longwave (red) receptors, we are able to distinguish those colours.

In order to best capture different wavelengths of light, cones should be evenly spaced across the spectrum of light visible to humans, which is about 400-700nm. When we look at the cone spacing of the honeybee (fig. 1), which is also trichromatic, we can see that even spacing is indeed the case. Similarly, digital cameras’ sensors (fig. 2) need to be nicely spaced out to capture colours. This even cone/sensor spacing gives a good spectral coverage of the available wavelengths of light, and excellent chromatic coverage. But this isn’t exactly how our own vision works.

Figure 3. The spectral sensitivities of the colour cones of a human. Reproduced based on Osorio & Vorobyev, 2005

Our own vision does not have this even spectral spacing (fig. 3). In humans and other catarrhines, the red and green cones largely overlap. This means that we prioritise distinguishing a few types of colours really well – specifically, red and green – at the expense of being able to see as many colours as we possibly might. This is peculiar. Why do we prioritise differentiating red from green?

Several explanations have been proposed. Perhaps the simplest is that this is an example of what biologists call evolutionary constraint. The gene that encodes for our green receptor, and the gene that encodes for our red receptor, evolved via a gene duplication. It’s likely that they would have originally been almost identical in their sensitivities, and perhaps there has just not been enough time, or enough evolutionary selection, for them to become different.

Another explanation emphasises the evolutionary advantages of a close red-green cone arrangement. Since it makes us particularly good at distinguishing between greenish to reddish colours – and between different shades of pinks and reds – then we might be better at identifying ripening fruits, which typically change from green to red and orange colours as they ripen. There is an abundance of evidence that this effect is real, and marked. Trichromatic humans are much better at picking out ripening fruit from green foliage than dichromatic humans (usually so-called red-green colourblind individuals). More importantly, normal trichromatic humans are much better at this task than individuals experimentally given simulated even-spaced trichromacy. In New World monkeys, where some individuals are trichromatic and some dichromatic, trichromats detect ripening fruit much quicker than dichromats, and without sniffing it to the same extent. As fruit is a critical part of the diet of many primates, fruit-detection is a plausible selection pressure, not just for the evolution of trichromacy generally, but also for our specific, unusual form of trichromacy.

A final explanation relates to social signalling. Many primate species use reddish colours, such as the bright red nose of the mandrill and the red chest patch of the gelada, in social communication. Similarly, humans indicate emotions through colour changes to our faces that relate to blood flow, being paler when we feel sick or worried, blushing when we are embarrassed, and so on. Perhaps detection of such cues and signals might be involved in the evolution of our unusual cone spacing?

Recently, my colleagues and I tested this hypothesis experimentally. We took images of the faces of rhesus monkey females, which redden when females are interested in mating. We prepared experiments in which human observers saw pairs of images of the same female, one when she was interested in mating, and one when she was not. Participants were asked to choose the mating face, but we altered how faces appeared to those participants. In some trials, human observers saw the original images, but in other trials they saw the images with a colour transformation, which mimicked what an observer would see with a different visual system.

By comparing multiple types of trichromacy and dichromacy in this way, we found that human observers performed best at this task when they saw with normal human trichromatic vision – and they performed much better with their regular vision than with trichromacy with even cone spacing (that is, without red-green cone overlap). Our results were consistent with the social signalling hypothesis: the human visual system is the best of those tested at detecting social information from the faces of other primates.

However, we tested only a necessary condition of the hypothesis, that our colour vision is better at this task than other possible vision types we might design. It might be that it is the signals themselves that evolved to exploit the wavelengths that our eyes were already sensitive to, rather than the other way round. It is also possible that multiple explanations are involved. One or more factors might be related to the origin of our cone spacing (for example, fruit-eating), while other factors might be related to the evolutionary maintenance of that spacing once it had evolved (for example, social signalling).

It is still not known exactly why humans have such strange colour vision. It could be due to foraging, social signalling, evolutionary constraint – or some other explanation. However, there are many tools to investigate the question, such as genetic sequencing of an individual’s colour vision, experimental simulation of different colour vision types combined with behavioural performance testing, and observations of wild primates that see different colours. There’s something strange about the way we see colours. We have prioritised distinguishing a few types of colours really well, at the expense of being able to see as many colours as we possibly might. One day, we hope to know why.  

James P Higham

This article was originally published at Aeon and has been republished under Creative Commons.

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The Colours of Jupiter

The swirling, toxic clouds of Jupiter’s North Temperate Belt are captured in this image from NASA’s Juno spacecraft which has been on the case since it was launched in 2011 – reaching Jupiter’s orbit about 5 years later. 
The picture was created by ‘Citizen scientists’ (as NASA calls them) Gerald Eichstädt and Seán Doran by tiling a bunch of holiday snaps from Juno’s feed. The image has been ‘colour enhanced’ which always takes the fun out of things a bit (it’s not really like that then is it?) but then, when you think about it, the colour of any celestial body is a little bit arbitrary so adding a bit of saturation and creative interpretation is hardly cheating…
Anyway, the raw images were taken in late October, 2018 as the little-probe-that-could swam past the big guy for the 16th time.
There’s a kind of Bruce Willis-inspired promotional video about Juno here.

JunoCam’s raw images are available here and NASA are quite happy for you to work them up.   
Image Credits: NASA/JPL-Caltech/SwRI/MSSS/Gerald Eichstädt/Seán Doran

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