Typography/Readability/Legibility

[Paul Trummel <trummel -at- U -dot- WASHINGTON -dot- EDU>]

A plethora of posts have recently appeared on the list that
relate to typography, readability, legibility, and typographic
definitions. This posting may serve to clarify some of the issues
recently raised and promote further discussion on typographic
style (visible rhetoric). For example, a correspondent asked for
a definition of the difference between a font and a typeface:

     Font: a single division within a typeface family
     eg. Times Roman, Times Italic, or Times Bold.

     Typeface: a family of fonts
     eg. all of the fonts within the Times classification.

Desktop publishing designers have adhered to the traditional
usage of these particular terms. However, they have created many
problems through a lack of understanding of traditional
typographic techniques, processes, and terminology. Consequently,
a number of anomalous definitions exist. These definitions create
communication problems that tend to compound themselves.

Others correspondents have used the terms readability and
legibility interchangeably and indiscriminately. A better
understanding of the terminology that has evolved over the past
500 years will probably help tyro graphic designers and technical
writers to structure their work more comprehensibly.

The following article originally appeared in the "IEEE
Professional Communication Society Newsletter" (USA), Janu-
ary/February 1993, and this expanded version will shortly appear
internationally in "Typo News" (European Community), the combined
newsletter of the Society of Typographic Designers (of which I am
a Fellow) and the Association Typographique Internationale.

Let's Make it Clear!
by Paul Trummel
Department of Technical Communication
University of Washington, Seattle, USA

The design of legible typographic images demands that graphic
designers consider the diverse considerations of authors,
readers, editors, publishers, and many other technological
mediators. They must then chose an appropriate medium and devise
an efficient plan. Such a plan, together with the inherent
perceptual attributes, education, and training of the designer,
constitutes the initial step toward legible output of
multivariate[1] typographic or kinetographic images. Designers
must, therefore, possess knowledge of the human factors that
relate to the communication process as well as the skills that
enable them to use electronic tools. This sophistication derives
from a comprehensive education and training in typography and
type design. It does not derive as a by-product of using elec-
tronic tools.

Typographic legibility[2] contains the properties of text/images
that symbolically represent readability[3]. It forms an integral
part of the design algorithms of visible language[4]. Therefore,
legibility results from an interpretation of readability: a prop-
erty of text that results from developing verbal language in an
easily understandable rhetorical style. It requires the expert
consideration of a set of infinitely adjustable, concatenated[5],
multivariate, overlapping, geometric modules and complexes known
as typographic style.

Graphic designers and typographers variably define the
typographic element in graphic design as either visible language,
visual language[6], or visual literacy[7]. This causes confusion
as visible language depends for clarity and purpose on verbal
language and requires literate comprehension, whereas visual lan-
guage does not. However, both visible and visual language embrace
arts, involve crafts, and adopt similar techniques. The
glossarial definitions show the contrast between visible and
visual language and describe the very different meanings. The
ambiguous term visual literacy has no place in graphic design.

Legible typographic design comprises a codirectional
concatenation governed by a reader profile that relates to style
or visible rhetoric[8]. The profile results from analysis of
comprehension levels relative to age, education, and culture. The
term kinetography[9] defines the combined verbal/visible,
rhetorical function of typography in technological environments.

The typographer must take three distinct actions to achieve
legibility:

1. Analyze and comprehend the author's and editor's
intention.

2. Translate the intention through symbolic reference into
typographic signs.

3. Arrange the typographic signs into recognizable and compre-
hensive gestalts.

Legible typography has two attributes: it serves as a separate
and independent sign and as an interpretable function. These
attributes relate to important processing considerations: as an
independent sign they include typeface selection with reference
to weight, height, stress, serif, x-height, extruders, and
medium; and, as an interpretable function they include type size,
character and word spacing, measure (line length), leading (line
spacing), spatial disposition, and grapholectic[10] affiliation.
All facets of the interpretable function affect and control the
use of negative space within geometric constructs.

Notably, geometric constructs (visible algorithms) contain the
factors that control typesetting and imagesetting and act as an
important guide for text and graphics integration. Composed as
grids based on Cartesian coordinates, they result from the design
function, relate to both text and graphics, and may ultimately
control a variety of output peripheral devices. An example of bad
typography might consist of randomly selected typeface (no
significance to the readable symbol), loose or tight character or
word spacing without grapholectic identity (no interpretable
function), and design without geometric consideration (no grid
coordinates).

For summary, typographic legibility contains the properties of
text/images that symbolically represent readability. It forms an
integral part of the design algorithms of visible language. Thus,
legibility results from an interpretation of readability: a
property of text that results from developing verbal language in
an easily understandable rhetorical style (verbal language). It
requires the expert consideration of a set of infinitely
adjustable, concatenated, multivariate, overlapping, geometric
modules and complexes that constitute typographic style (visible
language).

Typographic designers must possess knowledge of the human factors
that relate to the communication process as well as the skills
that enable them to use electronic tools. The knowledge and
ability to interpret readability into legibility derives from a
comprehensive education and training in typography and type
design. It does not derive as a by-product from using electronic
tools.

Glossary

[1] Multivariate: exhibiting diversity conditioned by the
variables in communication (human factors) and/or communications
(technology) criteria.

[2] Legibility: the property of text/images that results from the
symbolic aspects of readability and several other factors that
aggregate as design algorithms and typographic style.

[3] Readability: the property of text that results from the
development of verbal language written in an easily
understandable rhetorical style.

[4] Visible Language: a graphic art constituent and a
communication channel or medium, the counterpart of verbal
language, describes a system of arbitrary orthographic signs or
rebuses that correspond to phonetic sound or have specific
meaning. It also describes paragraphic, diacritical, and
extraneous signs (punctuation, accent, mathematical and orna-
mental signs). Visible language embraces typography, iconography,
and kinetography. It adds emphasis to, and helps the
interpretation of meaning in, chirographic, typographic, or rebus
statements, and parallels verbal language in the dissemination of
information.

[5] Concatenation: Unification of concepts or methods as a series
or system in which the cognitive or perceptual modules function
as links in a chain.

[6] Visual Language: a fine art constituent and a channel for
personal, cultural, edificatory, erudite, and subjective
expression. Visual language also deals with cultural
enlightenment, moral and spiritual uplift, scholarship, and
depiction of objects and ideas. It does not describe the
functions of graphic communication.

[7] Visual Literacy: this term contains ambiguities that do not
convey meaning. Visual describes sensory perception and literacy
describes cognitive process. Consequently, the conjoined words
become an incompatible term that classifies as non-sequitur
because it contains inferential supposition and paradox.

[8] Rhetoric: The theory and practice of discovering the most
effective means of persuasion. The art of public relations and
the presentation of images. The denotative or connotative,
persuasive, metaphoric, or metonymic use of both verbal and
visible language.

[9] Kinetography: a dynamic secondary orality, or technological
verbal/visible rhetoric, that applies to multivariate online,
interactive, and broadcast media.

[10] Grapholectic: Written vernacularisation of transdialectal
language.

Let's Make it Clear!
Copyright 1993 by Paul Trummel