Dating back to medieval manuscripts, text has often been highlighted using a particular distinct bright red. The contrast of black and red on a white background is highly visible and striking, and this has been reused many times, in a way which I have not noticed for other colors. I call these uses rubrication and collate examples I have noticed from many time periods. This design pattern does not seem to have a widely-accepted name or be commonly discussed, so I propose extending the term “rubrication” to all instances of this pattern, not merely religious texts.
Why this rubrication design pattern? Why red, specifically, and not, say, orange or purple? Is it just a historical accident? Cross-cultural research suggests that for humans, red may be intrinsically more noticeable & has a higher contrast with black, explaining its perennial appeal as a design pattern.
Regardless, it is a beautiful design pattern which has been used in many interesting ways over the millennia, and perhaps may inspire the reader.
Red is among the classiest of colors, as a glance through fine book editions reveals. What is snazzier than a good drop cap which has been “rubricated” (sometimes called “printer’s red”)? And yes, rubrication is usually red—hardly ever orange, or green, or purple, or any of the other possible choices.
Rubrication is not merely coloring everything red, but a careful use of some red against mostly black in order to emphasize important elements. We have red letter days for holidays, Christians will subconsciously associate red text with the words of Jesus Christ in typesetting the New Testament, some editions of the Qur’an put Arabic diacritics in red, and maps or charts may highlight key destinations in red while every other location is printed in black.
Further, I noticed that these all seem to use not just red, but almost the same shade of red: a certain bright but medium red, never another shade like a pink or a deep scarlet. That might be an artifact of traditionally using iron gall ink (eventually upgrading to “minium” lead pigments) and then everyone imitating it, but once I began paying attention to red/black combinations, like the famous “law of fives”, I began noticing it everywhere—as Bringhurst remarks, red is “the typographer’s habitual second color”.1 (One place I haven’t seen rubrication used well is in predominantly black settings, such as the increasingly popular “dark mode”.2)
I could imagine that being true in medieval times when rubrication started (iron gall-based rust/oxide pigments are surely extremely cheap compared to many things), but that seems like it should have stopped being a problem at least by the 1800s when synthetic dyes & inks were invented. It also wouldn’t explain the prestige of vermilion not merely as a red in general, but as a vermilion ink reserved for imperial use in calligraphy & documents in both the Byzantine & Chinese empires.
Edward Tufte, who highlights many examples like Florence Nightingale in his data visualization books and is a skillful user of rubrication himself3, notes in Envisioning Information 1990 (chapter 5, “Color and Information”, pg83–86), apropos of Byrne’s unique color-diagram book interpretation of Euclid’s Elements4:
Byrne’s colors keep in mind the knowledge to be communicated, color for information. Use of the primary colors and black provides maximum differentiation (no four colors differ more).5 This yellow, broken with orange, is darkened in value, sharpening the definition of its edge against white paper; and the blue is relatively light (on a value scale of blues), reinforcing its distance from black. In the diagrams, the least-used color is black, and it is carefully avoided for large, solid elements—adding to the overall coherence of the proofs by muting unnecessary contrasts.6
…in languages with fewer than the maximum eleven color categories, the colors followed a specific evolutionary pattern. This pattern is as follows:
- All languages contain terms for black and white.
- If a language contains 3 terms, then it contains a term for red.
- If a language contains 4 terms, then it contains a term for either green or yellow (but not both).
- If a language contains 5 terms, then it contains terms for both green and yellow.
- If a language contains 6 terms, then it contains a term for blue.
- If a language contains 7 terms, then it contains a term for brown.
- If a language contains 8 or more terms, then it contains terms for purple, pink, orange or gray.
In addition to following this evolutionary pattern absolutely, each of the languages studied also selected virtually identical focal hues for each color category present. For example, the term for “red” in each of the languages corresponded to roughly the same shade in the Munsell color system. Consequently, they posited that the cognition, or perception, of each color category is also universal.4
Are there deep evolutionary reasons for red being so important to human color vision, perhaps because red is overrepresented in nature in important things like blood or berries?8 I have to wonder why a color like green is not more psychologically important, though, as green is surely even more common than berries (which often aren’t red)—thanks to the inefficiency of chlorophyll in absorbing those particular wavelengths of visible light from our sun9—and human eyes are in fact physically most sensitive to green light in night vision. Why aren’t humans most attuned to green, the better to navigate jungles etc? (Is Rayleigh scattering involved somehow?) So this is a little puzzling.
“Many years ago—but not that many!—one of our printing & typesetting instructors said with great gravitas that ‘there are only two colors: red and black.’”
Below is a gallery of rubrication typographic or diagrammatic examples, which I’ve selected for their appearance or subject; they sorted in reverse chronological order, from roughly post-WWII, post-Renaissance, and Renaissance/medieval.
As expensive and restricted as materials were, and labor-intensive the process of manuscript copying, medieval and later scribes nevertheless accomplished great things, including effective use of rubrication, drop caps, and diagrams (some of which put most contemporary web designers to shame):
…if the text, or a new section of text, begins at the top of a page with no heading to mark it, a little fanfare will probably be required. The same is true if the opening page is busy. If there is a chapter title, an epigraph, a sidenote, and a photograph and caption, the opening of the text will need a banner, a ten-gallon hat or a bright red dress to draw the eye.
Fleurons (typographic ornaments) are often used to flag text openings, and are often printed in red, the typographer’s habitual second color. The opening phrase, or entire first line, can also be set in small caps or in bold u&lc. Another excellent method of marking the start of the text, inherited from ancient scribal practice, is a large initial capital: a versal or lettrine. Versals can be treated in many ways. Indented or centered, they can stick up from the text. Flush left, they can be nested into the text (typographers call these drop caps, as opposed to elevated or stick-up caps). If there is room, they can hang in the left margin. They can be set in the same face as the text or in something outlandishly different. In scribal and typographic tradition alike, where the budget permits, versals too are generally red or another color in preference to black.
When using white-on-black, what is the functional equivalent of red? A green? A blue? For all the traditional popularity among programmers of the classic monochrome monitor computer terminal green-on-black phosphor color scheme exemplified by the VT100—what I myself use—most dark mode designs I see currently seem to opt for a blue…↩︎
Tufte routinely uses rubrication in his graphs & sparklines to emphasize key numbers or points: his 2006 Beautiful Evidence, for example, uses red on practically every other page. The use of proprietary Bembo fonts and rubrication mean that even Tufte ads are recognizably by Tufte. (This does pose some challenges for the family of Tufte CSS packages for various formats: there are now open-source Bembo fonts, but do red links really work online? Some Tufte CSS implementations like Eric J. Wang’s go for it, and others do not.) The sheer number of Tufte uses makes it difficult to select any examples for this gallery.↩︎
Byrne’s edition is beautiful and unusual enough that there are at least two attempts at recreating it worth looking at: Slyusarev Sergey’s “Fancy Euclid’s Elements in TeX” for PDFs; and Nicholas Rougeux’s “Making of Byrne’s Euclid” on how he created a beautiful interactive HTML version.↩︎
Is saying that rubrication works because it ‘maximizes contrast’ question-begging?↩︎
Use of primary colors like Byrne (yellow/red/blue) highlights an additional advantage of rubrication for emphasis: it avoids problems with the most common forms of color blindness—pretty much everyone can see red or at least see the contrast with red.↩︎
While exceptions have been found to this flowchart and the Berlin & Kay results questioned, the red results (that it follows black/white darkness terms, and precedes all other colors, and red is consistently red cross-culture) appear to be supported by the subsequent data.↩︎
It’s unclear, though, why our infant brains chunk colors at all. In a 2011 study, a team led by researchers at Mount Sinai School of Medicine, in New York, found a mathematical formula that describes how inputs from the retina could result in the separation of colors into warm (white) and cool (black) tones, suggesting that the physical properties of our vision system may create natural “fault lines” in color space.10 Other researchers speculate that colors in our environments may cluster around certain shades, such as the bright red of blood and berries, or the solid green of fields and foliage. As babies, we may be primed to pick up on these statistical regularities.
Given how wasteful that seems, one might wonder about alternatives; there might have been earlier ones, leading to the Purple Earth hypothesis. Are there better chlorophylls which could absorb more light? Possibly, the bacteriochlorophyll absorb light that plants cannot, and are one of many suggested ways to improve photosynthesis efficiency.↩︎
Curiously, although Apple did make heavy use of rubrication at some times, like its 1995 Apple Macintosh Performa 600 Series User Manual, post-1997 Apple appears devoid of that technique. Did Steve Jobs not like red?↩︎
This is likely from Mark Lombardi: Global Networks, ed Hobbs 2003, which demonstrates rubrication on its cover, and in an homage to the artist, uses rubrication in the accompanying textual biography/discussion of Lombardi; it also uses sidenotes. Lombardi, incidentally, read Tufte’s Envisioning Information, and Richards et al 2003 speculates he was influenced by the Uboku Nishitani calligraphy example (also reproduced on this page)—personally, I suspect the typewriter & other rubricated diagrams were more influential. His use of yellow backgrounds is also Tufte-like.↩︎
The TikZ community uses rubrication heavily, as can be seen in the TikZ example gallery. Examples which use red:
- “Matrix multiplication”
- “Symmetries of the plane”
- “Tkz-linknodes examples”
- “The tkz-2d package”
- “Splitting of Hydrogen in different strong magnetic fields”
- “Seismic focal mechanism in 3D view”
- “Scheme of Greatest Common Divisor (GCD)”
- “SWAN wave model”
- “Principle of X-ray photoelectron spectroscopy (XPS)”
- “Phasor diagram”
- “Foldable dodecahedron with Calendar”/“Birthday calendar”
- “Drawing lattice points and vectors”
- “Block Diagram for TTL IC Multiplexer 74HC153”
- simple examples: “Rainbows—Sun ray entering a rain drop”/“The 3dplot package”/“GNUPLOT basics”/“Annotated manipulator”/“Andler optimal lot-size”/“Polarization state of light”
Another computer-generated work, Liza Daly’s Seraphs Voynich Manuscript parody, makes elegant use of a faded red font on sepia background with (usually) black illustrations, but because it uses it for all text rather than emphasis, I exclude it.↩︎
Tufte notes (pg142, Visual Explanations 1997) that Youmans’s diagrams are “accompanied by a hesitant and apologetic text that carries on about the possibility of unduly literal readings, as if diagrams are chronically threatened by misinterpretations”. However, Youmans’s textbook was aimed at schoolchildren, and appears to have been something of an innovation: he defends his “novel” “system of illustrating Chemistry” in his preface “To Students and Teachers”, and takes pains to include 2 pages of “Opinions of Distinguished Chemists and Educators”, testimonials that his “new Chemical Diagrams” are clear, correct, and conducive to childrens’ chemical education. When we consider the contemporary hostility of many educators to any kind of acceleration like SMPY or towards ‘young adult literature’, which might strain or damage fragile young minds, and reflect on how much greater such hostility may’ve been in 1856, we cannot fault Youmans for attempting to preempt such criticism.↩︎
For a good discussion of the various translations’ virtues & vices and what Burton was trying to achieve, see “The Translators of The One Thousand and One Nights”, Borges 1936.↩︎
Like most technologies, rubrication can be used for evil (Nazi/Communist propaganda) as well as for good… Speaking of famous flags, why not The Red Cross? Because the Red Cross organizations’ emblem is based on figure-ground inversions of the flag of Switzerland, which uses only red/white, with no black ever employed, and this inversion approach has carried through to its alternatives like the Red Crescent symbol.
Similarly for the Japanese Rising Sun Flag or current flag of Japan—there do not appear to be any notable official flags employing black, aside from, unsurprisingly, the emperor mourning protocol (aside from variants involving South Korea or the 1936 February 26 Incident).↩︎
Nazi art & typography are associated with both blackletter & also with Paul Renner’s sans Futura. This is because the Nazis themselves were divided about what to use, although the “Antiqua–Fraktur dispute” ultimately came down on the side of more conventional Latin/Roman scripts & the Nazis banned blackletter from government use.↩︎
I was amused to discover Fabre’s cover while skimming Public Domain Review essays, as the name Fabre rang a bell—not long before, I had read “The Sphex story: How the cognitive sciences kept repeating an old and questionable anecdote”, Keijzer 2013, criticizing the Sphex anecdote which Hofstadter & Dennett so enjoy. And imagine what phrase I ran into within the first screens of reading Fabre’s cat essay, but “red-letter day”! The Baader-Meinhof effect‽↩︎
1923 translation of Bohrs Atomteori, al-menfatteligt fremstillet by Lindsay & Lindsay, color plates apparently in original; note that several of the scans/e-books are incomplete & omit diagrams.↩︎
Isotype made heavy use of red as its default second color; see pg41–50, where the justification is primarily that many printers may only do black & red. Incidentally, I use the WP photo here instead of the online scans because they are low-resolution and the original copies may have been faded, so they do not convey the sharpness of the printing & the brightness of the red ink.↩︎