Skeleton type design explained

Today type design is dominated by the hegemony of the outline approach, but there is another one waiting for its revival. What the heck is that mystical method?

What is skeleton based type design

Skeleton-based type design (SBTD) is the approach to type design that leverages a skeleton of a letter stroke as a fundamental path for a nib to determine a letter shape. SBTD approach refers to a natural way of type creation — writing or handwriting and advocates it as a foundation for type design.

Compare to the outline approach where the shapes are defined by Bézier curves drawn around it, in the skeleton approach curves define only the skeleton of stroke. Besides thickness or even contrast of a stroke, a designer has to handle a rendering nib. Since the method emerges in one’s mind as spontaneously as in boy’s mind emerges an idea to pee the own name in the snow, SBTD is definitely the intuitive method.

Skeleton origin

The idea of skeleton based type design is as old as modern type design itself. In 1985 Gerrit Noordzij published his main influencing piece to skeleton based type design The Stroke — Theory of writing. He aims to break the gap brought by the invention of printing to typography by advocating underlying written quality of all letters.

“The stroke is the fundamental artefact. Nothing goes further back than the shape of a single stroke. We cannot postpone a shape by drawing outlines first because any drawing (outlines included) begins with a shape.”

— Gerrit Noordzij 1985

(Noordij’s interpolation matrix based on theory of stroke)

Noordzij explains that by stroke interpolation we can derive any letterform. However, the approach of interpolating stroke based on the stroke skeleton was not widely applied, rather faked by the outline interpolation technologies.

The skeleton based approach leverages the concept of Noordzij’s Theory of writing and turns it into the type design tool with its particular methodology. While the stroke approach conceptualises the inner quality of letter shape, the skeleton is the controller of the typeface model. Consequently, the methodology involves skeleton in booth phases for researching the typeface model plus design phases as a controller to manipulate with the model.

The fresh example of such approach was the redesign of Jonthson by Monotype. Here, the hairline weight served the demand of the skeleton in the research phase and also the controller for maintaining the unique character of its original model.


I love discussions about typography. They ordinarily lead to disputes lasting hours when both sides argue for the same object until each one finds they reason about the same thing but use different terms. What could be more embarrassing than this? Maybe stuck in kinky pyjama and “I love pussycat” cup on the street in front of accidentally locked door without keys. To avoid such polemics about nothing just due to the mess in terminology and ensure that all skeleton type designers speak the same jargon let’s first clarify our terminology.


The skeleton is the fundamental constructional prerequisite of any letterform. Technically, it is a notional line that leads a nib. By the form of a skeleton, we distinguish letters from each other. In large type families, common characteristics of the skeleton across typefaces are a crucial connector.

Nib shape

If a skeleton is a bone of the human body, then a nib shape is muscle bounded on a skeleton. Nib shape is the second prerequisite of a letterform and is responsible for a stroke contrast.

Different nib shapes, from the most primitive to the advanced and composed forms.

Nib adjustment

Every muscle can be stretched and relaxed. Likewise, we are adjusting a nib shape. Adjusting the nib shape allows us to control stroke contrast locally as if we were changing pressure or rotation of pointed nib.

Nib adjustments


Joining bones and muscles we can build a shape of a body. The stroke is a shape rendered by nib when following a skeleton. For the script letterforms are strokes composition final result.


Since the invention of printing press, type producers were able to intervene strokes by typographical corrections to enhance letterforms legibility. Most frequent intervention is stroke cut at the and of stroke, or optical correction in critical stroke joints breathe in more light. For human body it’s like clothes, sometimes they are only fashionable to express an idea, sometimes they are practical and often it’s just an entertaining human failure.

Interventions illustrated by the black dashed lines cutting the stroke.


Let’s put all together — bones and muscles and clothes to get a type form. The final form that human eyes perceive as a black shape defining its white and vice versa. The final forms delivered to a reader as a set placed next to each other. Therefore, type form consists not only of its shapes, hence undefined space around the form.

The resulting type from after applying the interventions.

Uncovering what is the skeleton approach to type design might be nothing new for the veterans. Nevertheless, it is necessary to distinguish it from its parent stroke approach which was too limiting to compete with the outline approach. Moreover explaining its terminology is necessary invoke appropriate expectations of type designers as well as design tools developers. Though, that is another topic for another blog post.

In a meanwhile try Letterink to make own skeleton typeface.