It is a recurring phenomenon that we tend to sort what comes in large amounts to be able to grasp it, for quicker reference, and to find it back more easily. Once organized, you don’t have to look at everything all the time but only consult the parts of your current interest. The vast world of type is a prime case. Grouping typefaces also breaks down the process of identifying them into a less challenging task.

Any categorization covers three aspects: 1. sorting in (this is what scholars and historians do, also type manufacturers), 2. reference (educating) and 3. taking out or finding back (this is what the user usually does). The aspect of finding a typeface though is crucial to many more people, every day, than the act of classifying them. You sort your CDs once and then only look at the respective shelf when you want to listen to Jazz in particular. This is why I think a (more) useful classification is one that helps the user to find and select typefaces and which is structured accordingly.

What happened?

Assigning names to typefaces and classifying them is a rather new occurrence in our 560 years of type. In the beginning, i.e. the first 400 years of typography, typefaces didn’t even have specific names. Foundries and printers called them by their size (which actually were names like “Paragon”, “Great Primer”, “Nonparaille”, not numbers). All type looked more or less the same anyway and was suitable for more or less the same jobs – continuous text. If a printer had more than one version of a roman text face available they gave them different numbers, e.g. “Great Primer Roman No.2”.

Then the industrial revolution happened. And with it the wish for louder and more eye-catching typefaces than regular Bodoni at 24 pt. Plenty of flashy new designs were invented, numerous variations in style and jobbing type were starting to get available. With this, people saw the need to give the novel things terms to communicate about them. But which? Most typefaces weren’t based on historic models where you could derive terminology from.

So type foundries all invented their own, more or less arbitrary designations for their new styles, e.g. “Egyptian” (because everything Egypt was super en vogue after Napoleon came back from his campaign), “Gothic” or “Grotesque” (because that new alien style seemed weird) for sans serif typefaces or “Ionic”, “Doric” and “Antique” for slab serifs. Not only the designs were becoming more individual but also the terminology, resulting in the problem that names were not universally understood anymore. Terms were determined by marketing, not by style or historic roots.

Still, the actual typefaces themselves were not given individual names like today. A foundry rarely had more than two or three “French Clarendons” on offer and an easy solution was to just number them.

Until around 1900 only the slightest to no attempts where made to sort or classify typefaces. Rather it was considered “redundant, impossible or utterly inconvenient”. One of the earliest endeavors was the system proposed by Francis Thibaudeau in 1921. It is solely based on the form of the serifs (as later did Aldo Novarese in 1964), which I regard less ideal, but up until this stage in type history, it admittedly was a characteristic feature picturing the different style periods rather fittingly. [schemes for “Uppercase” and “Lowercase”]

By the mid 20th century, with new type issued weekly, it became increasingly difficult to keep put with the developments and to obtain a working knowledge of the countless variants known. For the first time classification was regarded as a problem and serious efforts were made to establish a systematic approach to sort typefaces and to come up with an international solution.

The Thibaudeau system was developed further by Maximilian Vox (born Samuel William Théodore Monod) who published his version in 1954. Continuing with the same main groups as Thibaudeau, Vox’ unique invention are terms for groups derived from the names of the most iconic printers / examples (Garalde, Didone) or techniques (Manuale).

The Vox-system was – slightly modified – taken over by the ATypI (Association Typographique Internationale) in 1960 and later internationally adopted as a standard. Adapted versions were published by the German DIN in 1964 and as a British Standard in 1967.

The limitations of those systems

An ever growing market for typefaces and countless new variants in style show that the old systems like Vox put too much emphasize on the historical order and the early seriffed typefaces. At the same time they generalize greatly when it comes to sans and slabs. This is understandable when we regard the age they were created in. The popular and influential neo-grotesques of the late 1950s like Helvetica and Univers weren’t even issued back then and the international style – and with it the surge of sans serif type – was just starting to take off.

The original idea of Vox was to enable the combination of different groups and terms, like e.g. to have a Garalde sans serif (= humanist sans). This alas was never really implemented apart from variations in the British Standard and additional explanatory text for the DIN classification. A similarly overlooked detail is that ATypI originally suggested the simple structure to be further subdivided by their members / the different countries to their liking. ATypI also did not define the terminology since this was the point especially hard to agree on. Instead they assigned numbers to each group to allow comparison and the translation of different adaptions.

Unfortunately, those ideas are largely forgotten. In fact now with a fully international market and type community we see that it is exactly the diverse terminology that became a big obstacle. Neither the terms coined by the type foundries nor the ones used in published classification systems are anywhere near being internationally compatible. For example the French call sans-serif faces Antique, the Germans Grotesk, the Americans Gothic which on the other hand is the term for blackletter in European countries.

Unambiguous terminology might now be even more important than a coherent, rational approach to sort typefaces. Because before we even attempt to achieve a classification, we have to be able to communicate about type and letterforms with all parties involved – designers, printers, compositors, students, manufacturers, scholars, engineers and perhaps even laymen.

Two (new) different ideas
There are two different approach of classification which I regard more practical.

1. Classification according to form model

This is an idea based on the writing and letter-theories of Gerrit Noordzij which I first put together after learning calligraphy and typeface design in the Netherlands. It doesn’t follow Noordzij’s terminology exactly but his inspired me in the search for more “generic” terms, not connected to a certain style period, because I found that the historic ones can cause quite some confusion among beginners. What makes a brand new font an Old Style typeface and one from 1790 a Modern? Or what does Humanist, Renaissance and Garalde mean here anyway?

I expanded Noordzij’s theories into a layered system comparable to “bones, flesh and skin”. Most text typefaces can be differentiated according to a small number of basic form models. You could call these the bones or skeletons of a typeface. Those principles of form are largely determined by the former writing tools – e.g. the broad nib or pointed nib – and how the stroke contrast originally came into being.

1. dynamic, humanist form model: forms (contrast and structure) derived from writing with a broad-nib pen. Noordzij calls this type of contrast “translation”.
2. static, rational form model: forms derived from writing with a pointed pen = “expansion”
3. geometric form model: rather drawing the linear skeleton form with a round pen, like in Futura = no contrast

These three models, the underlaying structural principles, are also visible in the letter forms when you reduce the stroke contrast or remove serifs. They determine the impression and the application of a typeface to a very large extent. Of course, a beginning designer doesn’t understand terms like expansion or broad-nib pen any easier than French Renaissance. But what most of us can agree on is the general appearance of character shapes:

1. Writing with a broad-nib, held at a consistent angle, delivers an inclined course of contrast, open apertures and divers stroke width. This gives the letters a dynamic and varied general form and feel (also in the italics and caps, which follow the proportions of the Capitalis).
2. In writing with a pointed pen, the thickness of the stroke is related to the pressure put upon the nib during a downstroke, while other strokes remain thin. The axis is vertical with high but less modulated contrast and rather closed apertures. This gives the letters a more static, stiff impression. The letter forms (e.g. q, p, d, b) and the proportions of the characters are rather similar, especially the width of the caps.
3. the round nib renders linear, more “drawn” looking constructed forms (e.g. circular o) like in Futura or monoline scripts. Caps often follow the classical proportions of Capitalis.

The second level – the flesh – is about the equipment and features applied to the skeleton of a typeface. Those are serifs and stroke contrast, either strongly visible or just a slight contrast to achieve the impression of optical linearity. The actual form of the serifs – triangular, bracketed or straight – is not as determining in my mind as it was for Thibaudeau. One can incorporate these specific differences into the third “layer” of descriptives.

The third, the skin level, gives us the possibility to introduce an infinite number of finer differentiations between the main groups of typefaces to describe even the most singular feature someone could ever look for. Descriptives can address different forms of serifs, like bracketed or straight serifs in the traditional categories of rational serifs, Scotch Modern and Didone, or ornamented ones. Also decorative features like stencil, inline, shadow are possible or terms related to style or application like western, horror, comic or agate, typewriter, low-res are possible. This detailed graduation can also be seen as a collection of tags.

With this set at hand, all kind of typefaces can be easily described by combining the terms of the groups, just like Vox imagined it, too. A Tuscan typeface for example could be characterized as a face with modern skeleton, little stroke-contrast, bi-furcated serifs, western-style, chromatic, poster,decorative, shadow, display and so forth. Okay, this is probably not the unique, dedicated term most of us would like to have at their disposal for typefaces, but they describe the typeface appropriately.

The big advantage I see in this system is that the groups relate to the impression and to some extent also use of the typefaces. It is relatively easy to assign atmospheric keywords to the form models, like warm, open, friendly to the humanist model and rather regular, strict, formal to the rational form model. This helps the selection of typefaces enormously, because the impression and atmosphere you want to achieve is usually what you think of first when you start looking for a typeface. At least I do. Also, it aids combining typefaces as all fonts that stand in one vertical column here combine well and harmoniously, whereas mixing the horizontal neighbors is more tricky. If you are looking for a more contrasting combinations you can pair the typefaces diagonally. So, either stay in one form model or go for lots of difference.

This system was published in German speaking reference books and since then is relatively widely used in Germany. However, it is not flawless and sometimes difficult to adapt for real-life applications. The terminology stays my main construction site. Do people actually understand what is meant by “dynamic” and “static”? The latter was my replacement term for the initial “rational” but right now I tend to get back to this again, because I have a hard time describing a rationalized english roundhead or modern italic as “static”.

Also, one could argue that the problem of any taxonomical approach is, that a typeface can only be “one of those things” even if we think of it more like piles or fraying clusters and less of self-contained drawers. It’s not realistic to say that a typeface can only be serif or sans given the numerous semi-sans and semi-serif examples. In the same way do we know typefaces who happily live in the middle of the humanist and the rational form models. So, where to put those? I’d advocate to place them on the play-board near what determines the feel of the typeface most, even if we give up immaculate grouping for that. An alternative would be to introduce more piles or to find a way to assign a typeface to more than just one group or descriptive, like you can do in a database environment.

One would think that an interactive system solves exactly this problem but actually the adaption for FontShop’s applications was rather tricky. My system works surprisingly well as a simple list, because it brings the chronological order of the first few groups out more clearly. It works okay in a matrix, especially because you can change the axises (form models in horizontal order or vertical) and “enter” it from different sides. But sorting over 7500 typefaces from the FontShop catalog into a customized classification I made for their iPad app was a challenging acid test. The main reason for my problems was the set-up of their database though, which only allowed typefaces to be assigned to one class. This ultimately proved me that the world of type is not as simple (anymore).

2. Micro-Classification or tagging

A possible solution to this problem and another approach I grew very fond of in the last years is the micro-classification you can call tagging. It is at first a non hierarchical approach, which makes it far more flexible and user-centred, often even user generated. You could call it a democratic take on classification. If people subjectively regard this typeface as “holiday” or “girlish”, then why not have them find the typeface with those keywords. The problem with tags added by users though, or also by marketing people, is monitoring. I did this voluntarily for MyFonts in the past extensively (besides tagging typefaces) and was just stunned at times by the silly and ridiculous tags that were occasionally added to fonts.

Tagging of course works more or less only in a (interactive) database environment. The most consequent example for it might be the MyFonts website, but also other type vendors work with a similar system more or less successfully. Here, the browsing or search interface is crucial, as you see in the example of fonts.com with its long, unstructured list of keywords. What is most confusing here – on a page they call “classification” – are keywords like “serif”, “script” or “simplified chinese” next to “scary” on the same level. In my opinion, it would be practical to offer tags in a basic hierarchical order as an entry point to all those different styles of typefaces, different “levels” of keywords. For example displaying “serif” a different level of tag than “holiday”. Speaking to type manufacturers though I got an additional view. Some told me that sales went up significantly after they added more tags, and more informal tags that is. So, what should you do when you see that people find the typefaces they want this way. Should you force educate them, force your classification on everyone if it is maybe not even helpful to them?

However, the biggest issue in an international tag-system is the language, or again, terminology. French users might want to tag or look-up sans-serif typefaces under the term “Antique” while the search brings up a list of decorated slab serifs (see ambiguities mentioned before).

Stepping back

As I am busy with this topic for 14 years now I get really desperate at times. I can understand why my predecessors did not want to continue to bother at some point and why the discussion is preferably avoided at conferences. Although I had intensive experience from teaching and earlier tests, I was hoping to find some new clues in a small research. What are the more “weighty” characteristics? How do people distinguish typefaces?

Well, to cut a long story short, it was not as fruitful as I had hoped and just brought up what I already knew or suspected.

I confronted students and friends of different level of knowledge with a pile of type samples and let them sort those into groups however they wanted. After that I asked them to assign names to their groups. To break you the most disappointing outcome first – this last task did not bring up anything at all. They had a very hard time to name the groups. Students with some knowledge used the existing terminology, blending all systems they know of, i.e. called some dynamic or static, used Vox for other groups or the traditional Anglo-American terminology. The ones who did not have any education in typography were able to describe what they saw and sorted, but couldn’t come up with a single, catchy term. Well – what did I expect. This is not surprising at all.

What was verified is that they separated script or decorated faces from text faces first. Secondly they separated serifs and sans. As a third – and actually more pronouncedly than I thought – they separated typefaces with stroke contrast from linear ones. Even to the extent that some separated fonts that are supposed to look linear, thus with just small optical adjustments, like in Univers or Bureau Grotesque. My guess is that this comes due to the lack of other criteria they had at hand, e.g. not being familiar with the idea of form models for further distinctions. The form model was – not surprisingly – the most advanced, hence most difficult thing to recognize. It is obviously a fact that distinguishing typefaces must be learned.

“Unfortunately, many researchers in type classification become so involved they forget the basic purpose of any attempt to formalize a structure: simple communication.” — Alexander S. Lawson

Conclusion and outlook

The problem with research in any field is that you dive into a subject on such specialized and detailed level that you forget that your distance to the language and knowledge of the normal people gets greater and greater. It helps to step back every now and then and ask the actual user. A classification should help them to find, select and combine typefaces, and not the scholar in the first place. Or at least this is what I find is lacking right now. The historically savvy expert has sophisticated language and methods to describe letterforms of the past and maybe even present. But I, too, sometimes forget that others don’t easily see those differences in typefaces that I can make out in seconds. I want to find a tool that also helps entry-level-users of type to recognize the differences and similarities among typefaces and find clues about their potential use.

My hope is to be able to combine all those different approach of classification into a flexible system that works on several levels of sophistication – for beginners and experts. We cannot abandon all old systems, and even less so, all the different terminology established over the years. We have to come up with a way how to integrate all this into a new scheme and explain it comprehensibly.

My proposal works well with most of the traditional groups of text faces and it follows the historical order in the serif categories. At the same time it is open to new additions to the typographic palette. One can easily incorporate different levels of descriptives: form-model, main formal features (serifs, contrast), and detailed features and associative terms. The third level could work as a user-centric tag collection. In a database environment all those level of descriptives would be assigned as tags anyway, just differently displayed in different user scenarios. Because the main illusion I/we have to give up is to think that a typeface can only be “one thing” – either sans or serif, either Old Style or Modern. Groups of typefaces shouldn’t be pre-filled buckets anymore, but rather a customized set of fonts at my disposal when I select “serif”, “rational” and maybe other key words.

The challenge now is to translate a collection of tags into a versatile visual form that can be used in teaching, talks, and publications, displaying the different levels of descriptives. Maybe the exact visualization can be different every time and adapted to the specific task. But what we need is a basic understanding and common language to know what we are talking about.

Tinkering with the wheel alignment of a car that might turn out not to have an engine seems pointless, especially if you haven’t even decided where it is to which you wish to drive.

This actually fits all design processes. No, life in general.

Humanist (Serifs, Sans, Slab) a’s mostly have an open upper counter and a rather small bowl; the lower half of the e has an open, friendly »mouth«, whereas the eye in the upper half is usually small. R has a diagonal, often long, maybe swashy tail. The uppercase letters are all of different widths, following the proportions of inscriptional Imperial Roman capitals (Capitalis Monumentalis).
If the typeface has contrast the stroke is likely to be thickest north-east and south-west (rotational symmetric, you can draw a diagonal line trough the thinnest parts). In the venetian subclass the e has a diagonal crossbar.
If the typeface has serifs they are bracketed and often asymmetric.

Transitional typefaces have more regular forms. The a and e are rather open, but in general the letters are not as lively and divers as in a humanist face. R has a diagonal tail, the widths of the uppercase are more equal. Stroke contrast is mostly symmetrical to a vertical axis. Serifs are bracketed and also more symmetrical. These typefaces stand inbetween Humanist and Modern, hence the name.

Modern typefaces, like Didones but also Grotesques have rather closed forms of e and a. Caps are of the same widths and more narrow, also the lowercase letters look comparatively alike (b, d, p, q). The R has a more vertical leg [I miss the proper english terms for that].
In the Didone style the stroke contrast is extremely high with a vertical axis, serifs are very thin and not bracketed. There is a subclass with bracketed serifs, like Century for instance, for which we are all still looking for a good name.

So viele verschiedene Gruppen sehen in bunt toll aus. Aber die Einteilung finde ich nicht in allen Punkten toll, die ersten beiden Bezeichnungen eher unglücklich gewählt. »Schriften vor Gutenberg« sind natürlich zeitgenössische Interpretationen wie z.B. Carolina, Duc de Berry uws. Aber warum dann nicht auch Ondine? Diese steckt bei den Breitfeder-Schriften.

Anstatt des Begriffs »gotisierende Schriften« fände ich »gebrochene Schriften« weniger missverständlich, vor allem, da sich so bizarr klingende Unterkategorien wie gotisierende Renaissance-Schriften und gotisierende gotische Schriften ergeben.

Auch bei den einfacher benannten Gruppen würde ich einiges anders zuordnen, die Times eher zu den Barock- als den Renaissance-Schriften stecken, Corporate A eher zu den klassizistischen. Etwas unglücklich finde ich die Solex in der Gruppe der »ursprünglichen Grotesken«, passt sie doch fast besser zu Unit und Fago, die bei den serifenlosen Antiquas eingeordnet sind. Wenn Melior eine »Clarendon« ist, wieso ist Linoletter nur eine serifenbetonte Variante? Genau wie Thesis Serif, wohingegen die sehr ähnliche Caecilia eine Egyptienne ist. Mmh.

Die Einteilung in die Gruppe »zweigliedrige Schriftsippe« wird der Lucida Familie mit ihren 10–14 Varianten nun überhaupt nicht gerecht. Genauso bestehen auch Fedra, Stone und Thesis aus mehr als zwei Teilen. Bei letzterer, Diverda und Syntax zeigt sich dann zudem, wie schwierig eine Einteilung in »Schriftsippen« als Extragruppe ist. Die einzelnen Schriften sind jeweils auch für sich eingeordnet.

1. Vor Gutenberg
1.1 Römisch: Columna Solid, Herculanum, Pompeijana
1.2 Frühchristlich: Omnia, Unciala
1.3 Frühromanik: Carolina
1.4 Gotik: Clairveaux, Duc de Berry, San Marco

2. Gotisierend
2.1 Gotik: Johannes G, Weiss Rundgotisch, Wilhelm Klingspor Gotisch
2.2 Renaissance: Alte Schwabacher, Fette Fraktur, Luthersche Fraktur, Walbaum Fraktur

3. Antiqua
3.1 Renaissance: Bembo, Californian, Centaur, Charter, Dante, Documenta, Electra, Elzevir, Fedra, Galliard, Garamond, Hollander, Janson, Minion, Perpetua, Poetica, Renard, Sabon, Stone Serif, Syntax Serif, Times, Trump Mediäval, Van Dijck
3.2 Barock: Baskerville Handcut, Caslon Display Typo, King’s, Coranto, Corporate A, Rotis Serif, Utopia
3.3 Klassizistisch: Bodoni, Centennial, Didot, Onyx, Scotch Roman, Walbaum

4. Serifenbetont
4.1 Egyptienne: Caecilia, City, Corporate E, Diverda Serif, Egyptienne, Lubalin Graph, Officina Serif, Rockwell, Serifa, Soho
4.2 Clarendon: Clarendon, Excelsior, Melior, Nimrod, Renault
4.3 Italienne: Wanted
4.4 Varianten: American Typewriter, Latin, LinoLetter, Lucida Serif, Mesquite, Swift, The Serif

5. Serifenlos
5.1 Ursprüngliche Grotesk: Akkurat, Basic Commercial, Corporate S, Eurostile, Franklin Gothic, Monotype Grotesque, Neue Helvetica, News Gothic, Newut, Solex, Univers, Vectora
5.2 Geometrische Grotesk: Avenir, DIN, Futura, Kabel, Neutraface, Stratum, Theo Ballmer
5.3 Serifenlose Antiqua: Dax, Diverda Sans, Fago, Fedra Sans, Frutiger, Gill Sans, FF Info, Lucida Sans, Meta, Myriad, Officina Sans, Optima, Rotis Sans Serif, Scala Sans, Stone Sans, Syntax, The Sans, Thordis Sans, Unit, Vesta, Veto

6. Schriftsippe
6.1 zweigliedrig: Diverda Sans/Serif, Fedra Sans/Serif, Lucida Sans/Serif, Officina Sans/Serif, Stone Sans/Serif, The Sans/Serif
6.2 dreigliedrig: Corporate A, S, E, Syntax, Syntax Serif, Syntax Letter,
6.3 viergliedrig: Rotis Sans Serif, Rotis Semi Sans, Rotis Semi Serif, Rotis Serif

7. Dicktengleich
7.1 Serifen: Courier, Kettler
7.2 Serifenlos: Letter Gothic, OCR A, OCR B, Simple, Thordis Sans Mono

8. Handschriftlich
8.1 Spitzfeder: Englische Schreibschrift, Palace Script, Petras Script
8.2 Breitfeder: Arabella, Medici Script, Ondine, Oxford, Zapfino
8.3 Pinsel: Mistral
8.4 Redisfeder: Kaufmann, Monoline Script, Sütterlin
8.5 Filzschreiber: ABC Schule, Caflisch Script, Syntax Letter

9. Dekorativ
9.1 Zierschrift/Dekorativ: Bifar, Mambo, Myriad Tilt, Remedy, Toolbox
9.2 Schablone/Stempel: Stencil
9.3 Geometrisch: Tephra, Industria, Jan
9.4 Raster/Punkt: Dot Matrix
9.5 Amorph: Blur, Tyrell Corp, Kosmik, Mineru, Stamp Gothic
9.6 Varianten: Arcadia, Arnold Böcklin, Triface/Trifill, Trixie

10. Bildschirm
10.1 Pixel: Alaska, Ceriph, Executive, Fuego, Hooge, Idea, Neostandard, Phantom, Pixot, Planeta, Protege, Sensation, Spam

11. Symbole
11.1 Sonderzeichen: Zapf Dingbats, European Pi, Mathematical Pi
11.2 Piktogramme: Holiday Pi, Mac Key Caps, Technical Pi, Textil Pi, Warning Pi

Vielleicht bin ich, was Klassifikationen anbelangt übersensibel. Aber ich finde, hier wären weniger fein eingeteilte Gruppen unkomplizierter gewesen (siehe Schriftenfächer von Michael Wörgötter). Die Untergruppen würde ich mir konsistenter wünschen z.B. auch mit eine Varianten-Kiste in allen Kategorien. Die gibt es nämlich ebenso bei den Serifen- und Serifenlosen Schriften.

Die Suche nach der optimalen Einteilung ist also noch nicht zu Ende.

Hier eine Passage aus meinem Buch Buchstaben kommen selten allein (gekürzt).

Worin unterscheiden sich Schriften?
Am augenscheinlichsten kann man zwischen Serifenschriften und Serifenlosen unterscheiden. Das zweite wichtige Merkmal ist ihr Strichkontrast und dessen Verlauf im Buchstaben. Dabei kann man drei verschiedene Grundprinzipien erkennen:
1. von dem Schreiben mit der Breitfeder ausgehend (Renaissance-Charakter, dynamisches Formprinzip, Translation)
2. von der Spitzfeder herrührend (klassizistischer Charakter, statisches Formprinzip, Expansion)
3. von der Redisfeder inspiriert (konstruierter Charakter, geometrisches Formprinzip, kein Strichkontrast)

dynamisches Formprinzip:
schräge Kontrastachse, offene, runde Formen des a, c und e, zweibäuchiges g, schräger Strichansatz, differenzierte organische Form. Versalien orientieren sich in Form und Proportion an der römischen Kapitalis, gerader diagonalen Abstrich bei R.
Diese Merkmale gelten auch bei Verringerung des Kontrasts und dem Verstärken oder Weglassen der Serifen.
typische Vertreter: Garamond, Barmeno, Syntax, Caecilia, Swift

statisches Formprinzip:
gerade Kontrastachse, hoher Strichkontrast, statische, geschlossene Buchstabenformen sichtbar bei R, a, e und s, regelmäßige, ähnliche Formen z.B. bei b, d, q und p. Versalien sind alle ähnlich breit, Abstrich des R geht gerundet nach unten. Diese Merkmale gelten auch für die Serifenbetonten und Groteskschriften ohne Strichkontrast.
typische Vertreter: Bodoni, Britannica, Helvetica, Boton, Clarendon

geometrisches Formprinzip:
kein Strichkontrast, konstruierte Formen, O und andere Buchstaben sind optisch zirkelrund. Versalien folgen den Proportionen der Kapitalis, R mit diagonalem Abstrich.
typische Vertreter: Futura, Memphis, Tekton, Isonorm

Klassifikation nach Formprinzip
Die hauptsächlichen Unterscheidungsmerkmale von Schriften sind also die Serifen, gefolgt vom sichtbaren Strichstärkenunterschied. Nach diesen
Ausstattungsmerkmalen kann man alle Schriften waagerecht in Hauptgruppen unterteilt. In der Senkrechten wird nach den drei Formprinzipien unterschieden, ergänzt um eine Gruppe für dekorative und weniger eindeutige Schriftentwürfe.

Möchte man zwei Schriften mischen, ist es in der Regel gefahrlos Vertreter eines Formprinzips zu kombinieren (z.B. Garamond + Syntax). In der Übersicht untereinander stehende Schriften, also unterschiedlichen Formprinzips, harmonieren dagegen meistens nicht so gut miteinander (z.B. Caecilia + Helvetica).

Formprinzip oder DIN-Klassifikation?
Die Einteilung nach Formprinzip steht im klaren Kontrast zur amtierenden deutschen DIN-Klassifikation 16518 mit ihrer historischen, teils recht groben Einteilung. International findet man noch weitere unterschiedliche Methoden der Klassifikationen und auch jeder Schriftenhersteller strukturiert seine Bibliothek nach eigenen Kriterien. Sehr verbreitet ist die Einteilung von Maximilian Vox, die in den 1960er Jahren Vorbild für die DIN-Klassifikation war. Die Gruppennamen sind für den normalen Anwender jedoch recht schwer nachzuvollziehen.

Die Klassifikation nach Formprinzip lässt sich in der Tiefe um die historisch gewachsenen Untergruppen erweitern. Zum Vergleich links die Einteilung der DIN und Bezeichnung des Vox-Systems.

Noch ein paar Gedanken zur Klassifikation in englisch/some thoughts on classification in english

There are subclasses like “Scotch” within this group, typefaces designed for the tricky printing conditions of newspapers like Ionic and the Legibility Group, or some sturdy workhorses derived from typewriters. But more importantly – where do we draw the line between bracketed Modern and bracketed Slabs like Clarendon (for which we need a good term as well)? At Madison?

In my work on classifications I always looked for “generic” terms which are not connected to a certain style/period in history for I experienced that this causes quite some confusion among beginners. What makes brand new cool xxx a Baroque typeface? (and what does Humanist, Renaissance and Garalde mean anyway?)
I based my classification and terminology on Gerrit Noordzij’s theory of writing, which distinguishes two major groups within textfaces (see his book The Stroke):

1. Forms (contrast and structure) derived from writing with a broad-nib pen = Translation
2. Forms derived from writing with a pointed pen = Expansion

Adding the traditional German approach of foundational writing – “drawing” the linear skeleton form with a round pen, like in Futura – we end up with three groups.

These three form models, the underlaying stuctural principle, can be found in almost all typefaces regardless whether they’re seriffed, sans, slab, cursive, fat or extended. You could call it a meta-attribute (see Noordzij’s 3d-type-cubes).
Of course, a beginning designer doesn’t understand terms like expansion or broad-nib pen any easier than French Renaissance. But what most of us can agree on is the general appearance of character shapes:

1. Writing with a broad-nib, held in a certain angle, delivers an inclined course of contrast, open aperture and divers stroke width. This gives the letters a dynamic and varied general form and feel (also in the italics and caps, which follow the proportions of the Capitalis).
2. In writing with a pointed pen the thickness of the stroke is related to the pressure put upon the nib while drawing a stroke. Because this is applied to the down-strokes only, the axis is vertical with high but less modulated contrast and rather closed aperture. This gives the letters a more static, stiff impression. The letter forms (e.g. q, p, d, b) and the proportions of the characters are rather similar, especially the width of the caps.
3. the rounded-nib renders linear, more “drawn” looking constructed forms (e.g. circular o) like in Futura or monoline scripts. Caps often follow the classical proportions of Capitalis.

These meta-classes can easily be divided into subclasses for serif, sans and slab, and sub-subclasses as many as you’d like to.
To sum up some terms

1. dynamic form model:
   broad-nib, Translation, Humanist, Renaissance (Venetian, French), Old Style, Aldine, Garalde, Baroque, Reales, Transitional; Humanist Slab; Humanist Sans; Cancellaresca, Chancery Script
2. static/rational form model:
   pointed-nib, Expansion, (Neo-) Classicism, Didone, Modern, Scotch, Clarendon, Egyptienne, Slab, Italienne, Latin; Gothic, (American) Grotesque, Grotesk (Neo-Grotesque), Realist; Copperplate, Roundhand
3. geometric form model:
   rounded-nib; Egyptienne, Geometric Slab; Geometric Sans; monoline Scripts

((oh, I’m there – have to get off the train … to be continued and illustrated one day))

See also: The difference between Humanist, Transitional and Modern typefaces