Taking advantage of this first project, I want to share a bit about what I’ve learned in recent years. I also have a very specific vision of how legibility should be articulated in typography, and I want this to be the platform where I present that vision. After all, Tiphares is a product of my experience but also of the science of legibility.

Legibility in typography is a topic that both designers and scientists revisit repeatedly, but the lack of clear guidelines or consensus creates a certain fatigue. Studies often contradict each other—or simply rehash the same debates every few years—without moving the conversation much further1Beier, S. (2016). Letterform research: An academic orphan. Visible Language, 50(2), 64. | Lund, O. (1999). Knowledge construction in typography: The case of legibility research and the legibility of sans serif typefaces (Master's thesis). University of Reading..

I find it useful to view the history of legibility from two angles: psychology and design. In this article, we’ll briefly review the psychological perspective. Although historian Richard L. Venezky attributes the first comparative study of legibility to type cutter Alexandre Jacques Anisson-Dupéron (a fascinating story, but one we’ll leave for another day)2Venezky, R. L. (1984). The history of reading research. In P. D. Pearson (Ed.), Handbook of reading research (Vol. 1, pp. 3-38). Longman., the first studies that truly merit attention were conducted by psychologists and psychophysicists in the late 19th and early 20th centuries, such as the Frenchman Emile Javal (1839 – 1907) and the American Edmund B. Huey (1870-1913).

From the beginning, these researchers grappled with the meaning and nuances of abstract concepts like readability, legibility, visibility, or discriminability. Moreover, language barriers further complicated the issue, leaving it at the mercy of translators. For example, Javal coined the term visibilité parfaite to denote when an observer can see every detail of a letter, and lisibilité (legibility? readability?) to denote the point just before reaching the limit of reading3Javal, É. (1906). Physiologie de la lecture et de l’écriture: Suivie de déductions pratiques. Félix Alcan., which today is more universally known as ‘acuity limit’.

Before them, a researcher named Cattell (1885) made a discovery that complicated the study of legibility for years, making it seem irresolvable. Using a tachistoscope, a machine that allowed showing an image or text to a subject for a controlled amount of time, Cattell discovered that people perceive groups of letters as quickly as isolated letters, and even faster if they are organized into known words rather than random combinations4Cattell, J. M. (1886). The time it takes to see and name objects. Mind, 11(41), 63-65. This finding contrasted with distance reading experiments, where isolated letters were usually perceived as well or better than groups of letters. In the realm of legibility, this phenomenon is known as the ‘word superiority effect’. The major implication of this discovery was that the individual perception of a letter (legibility?) was no longer decisive in certain situations; instead, its behavior as part of a word (readability?) became more relevant.

The discourse of the following decades of the 20th century was dominated by a school of thought called ‘behaviorism’, founded by John B. Watson (1878–1958). Behaviorists only believed in what could be measured, so they began to talk about legibility in terms of how many words per minute could be read or how far one could distinguish a letter. Factors such as comprehension or comfort, which are much more subjective, were of no interest to them.

Miles Tinker (1893 – 1977) and G. Paterson (1892 – 1961) fit precisely into this school of thought. This duo with a detective-like name are probably the most prolific researchers in the history of legibility and typography. Perhaps because of this, they remain a reference in many type design texts even today, despite the fact that their work is outdated and obsolete. I’ll discuss them, but I’ll try to make this the last time.

As good behaviorists, Tinker and Paterson saw the calculation of words per minute as an indisputable solution to the problem of legibility. Discrepancies caused by other measurement methods such as distance reading or reading under low visibility conditions were simply resolved by assigning a universal readability value to all ‘normal’ fonts. Clear differences only arose in the case of very novel and baroque designs, and those were the ones that mattered most. In 1940, they published How to Make Type Readable 5Paterson, D. G., & Tinker, M. A. (1940). How to make type readable. Harper & Brothers, probably the most influential text on the topic in the first half of the 20th century, where they declared that they had tested over 30,000 participants. Today, where some form of compensation for study participants is common, no one even approaches those numbers. My thesis, for example, employed the daunting number of 22 participants, all of whom were appropriately compensated.

One of the contemporary researchers who proposed a different approach to legibility was Matthew Luckiesh (1883 – 1967). I’ve always found Luckiesh to be a much more interesting and astute researcher than Tinker. Both he and his colleague Frank K Moss (1898 – ?) were lighting engineers, although Luckiesh also worked as a consultant for Mergenthaler (the grandfather of Linotype) after his studies on legibility. During the 1930s and 40s, they sought to find a correlation between lighting and visual fatigue. They assumed that the more demanding the task, the clearer the effects of fatigue would be, so they looked at reading as a task to measure this fatigue. To articulate their ideas properly, they invented the visibility-meter. A pair of photographic filters that increased density through rotation, reducing apparent brightness and clouding reading 6Luckiesh, M., & Moss, F. K. (1935). Visibility: Its measurement and significance in seeing. Journal of the Franklin Institute, 220(4), 431-466. When they experimented with their new toy, they realized that the characters that scored well on the visibility-meter did not necessarily score equally well in distance reading or reading speed, as distinctive and eye-catching features seemed to be an advantage in that context and a disadvantage in others. To solve this problem, they introduced the concept of ‘readability’. In 1939, they published The Visibility and Readability of Printed Matter 7Luckiesh, M., & Moss, F. K. (1939). The visibility and readability of printed matter. Journal of Applied Psychology, 23(6), 645., where they defined visibility as “the intensity of a psychophysical stimulus which evokes visual perception and discrimination.”; and readability as “the integral effect of physical factors which influence ease of reading”, with visibility being one of these factors. They explicitly separated readability from comprehension and also stated that they were too cool to use the term legibility, due to its excessive use and the difficulty in providing a clear definition.

Difficulties in replicating their findings by other colleagues, coupled with the public criticism by Tinker in a series of articles8Tinker, M.A. (1946). Validity of frequency of blinking as a criterion of readability. Journal of Experimental Psychology, 36(5), 453. | Tinker, M.A. (1945). Reliability of blinking frequency employed as a measure of readability. Journal of Experimental Psychology, 35(5), 418, led to Luckiesh’s work falling into disrepute. Besides being prolific, Tinker proved to be not very receptive to diverse opinions and harshly criticized anyone who dared to propose different criteria. This public confrontation and the inability of the researchers to unify the discipline led some to ridicule the subject. Psychologist Irving Whittemore, in response to the series of articles between Tinker and Luckiesh, expressed his reservations through a satirical publication in the magazine Print9Whittemore, I. C. (1948). What do you mean, legibility? Print magazine., where the psychologist ‘Tinkerson’ debated with the director of the University Press about readability. At one point, one of the characters asks a question that would become a classic reference in legibility articles:

“Do you mean (1) easy to read fast, (2) easy to read at a distance, (3) easy to read in dim light, (4) easy to read when you haven’t your glasses, (5) easy on the brain, (6) not tiring to the eyes, (7) possible to grasp in big gulps of meaning, (8) pleasant to read, (9) inviting to the eye, or (10) something else?”.

With this question, Whittemore challenges the debate and the universalist intentions of reading researchers. Despite this, researcher William Berkson believes that Tinker’s authoritarian tone prevented people from daring to propose or defend new ideas vigorously until the fall of behaviorism10Berkson, William, y Peter Enneson. «Readability: discovery and disputation», 2019. (around the 70s).

In the following decades, the expansion of cognitive psychology as a discipline favored the emergence of multiple profiles approaching the problem of legibility and reading from very different perspectives. Perception researchers focused on word recognition and studied perceptual processes and patterns using well-defined stimuli; those with a background in memory processes and verbal learning theory concentrated on comprehension, etc. This exponential expansion of knowledge began to be organized around reading models.

Reading models are procedural frameworks that organize various areas of knowledge, transforming them through seemingly simple but highly specialized processes into exhaustive sets. In general, existing reading models focus only on a limited area of the reading process, and often do not interact with each other or their relationship is hard to explain. Although the more intricate models have managed to elucidate certain phenomena and have fallen short in explaining others, the concept—supported by empirical evidence—that different reading processes have local rather than universal requirements, found a very favorable environment to develop¶.

As mentioned in the previous blog entry, the acceptance that readability and legibility lack absolute existence has led scientists to focus their research on measurable issues. Nonetheless, researchers with a broader spectrum attempt to contextualize their work. For example, two of the most prominent researchers in the past four decades, Keith Rayner (1943-2015) and Gordon Legge (1948-), have relatively similar approaches. Rayner, known for his studies on the visual-motor system, defined legibility as “how easy the letters in a word are to encode”, focusing on the recognition phase that starts the lexical process 11Slattery, T. J., & Rayner, K. (2010). The influence of text legibility on eye movements during reading. Applied Cognitive Psychology, 24(8), 1129-1148. https://doi.org/10.1002/acp.1623. Legge defined legibility as “the perceptual properties of text that influence readability”. Although he does not strictly define readability, it is inferred that he uses it to refer to the accessibility of a text’s meaning, arguing that even a text with complex vocabulary or difficult syntax can be “highly legible” 12Legge, G. E. (2006). Psychophysics of reading in normal and low vision. CRC Press..

So, returning to the question that heads this article: ‘What is legibility?’ Although it is not a topic that particularly interests science today, many scientists consider it fundamental for any researcher discussing legibility to define the concept beforehand, and the usefulness of this practice is easy to recognize. After all, as we have seen, the same typography does not perform equally depending on the task, so when a designer talks about ‘legibility’, it is good to ask if they are trying to answer any of Whittemore’s questions or something completely different.

In this regard, I believe that type designers should propose their own definition of legibility and not be afraid to deviate radically from what science establishes. The primary interest of science is the human being, and how their psychophysical processes react to typography or adapt to reading. In contrast, the interest of a designer is in the letter and how it adapts to the human being and to the environment and context. Readers can always optimize their reading experience by making the text size larger. Researchers usually play with pre-defined weights, widths and artificial spacing distributions. For a type designer, these are not the only answers.

In a future post, I will discuss my own definition of legibility (sorry, I don’t want to make these posts too long), but in general, to the question of “what is Legibility?” I would always respond “Legibility of what, under what circumstances, and for whom?” This is a variant of the question that I’m sure we’ve all heard at some point: “What is the best typeface?”; “The best typeface for what?”.

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