• Riesling Dong

Obsidian, designed by algorithms

Obsidian's aesthetic mimics the dawn of type design, but is completely computerized.

Hoefler & Co. Methods of type design have shifted over the years — from movable type printing presses to copper plate engraving to modern design software — but fonts are still largely created by hand. And with globally successful fonts containing nearly 600 characters in various languages, a single typeface with several weights and styles can take a year or more to design.

Now, design company Hoefler & Co., which names Nike, Starbucks, and Barack Obama among its clients, has figured out a way to expedite the process: algorithms. 

The roots of the Obsidian typeface begin with Surveyor, a family of fonts designed at H&Co which revive the style of roman and italic letterforms native to engraved maps of the nineteenth century. The more time we spent with this historical material, the more charmed we were by engraved title pieces like the one above, in which letters are decorated with elaborate hatching on their faces and in their shadows.

Modern typeface designers draw fonts by manually plotting every line and curve in every letter form. Even simple shapes require complex geometry: above left is a straightforward ampersand, constructed of 36 connected curves. Elaborate typefaces like Obsidian, at right, are unmanageably tortuous: this ampersand alone would require the designer to draw and coordinate 284 different curves, defined by placing more than 1,100 points. Early in the development of the project, it was clear that even the process of sketching possible directions would need the help of a new and heretofore unimagined set of tools.

Building on a font whose exterior outlines had been completed, H&Co Senior Designer Andy Clymer created a suite of proprietary tools to help apply complex decorations to font outlines. The process begins by dividing each of the more than 1,400 characters in the family into individual “panels” (above right), each defined by western and eastern edges, shown here in green and orange. These panels would serve as the foundation of the ornamentation to follow.

Once the panels are established, a script divides each panel into slices, giving the font’s designers their first glimpse of what a “hatched” version of the typeface will look like. The number of slices for each panel can be adjusted independently, to give the resulting letter form a more consistent texture: at right, different parts of this ampersand are divided into four, five, or six slices.

Having chosen the number of slices for each panel, the tools then divide each slice into a series of shorter segments. The angle of each segment is compared to the direction of an imagined light source, to determine how “bright” it should be. Segments on the western and eastern faces are oppositely illuminated, to create the illusion of dimensionality.

Finally, in its most complicated bit of mathematics, the software interprets the brightness of these connected segments as a set of continuous curves, and generates its first draft as a working font. This font is used to create proofs that demonstrate the design in a variety of contexts, which the project’s designers review together.

A refined version of the tools allowed different parts of a character to be illuminated differently, to achieve a more consistent overall effect. (1) A raked light from above gives a ‘ball terminal’ greater clarity; (2) rotating the light source provides more balanced illumination to the banana-shaped bowl on the left side; (3) side lighting the main diagonal stroke gives it a defining contrast. The final character (4) is a composite of these different highlights.

A humble user interface conceals complex inner workings. Clymer’s shading tools were written in Python— long the language of choice for managing font data — and built as an extension for the RoboFont font editor. Intuitive, modular libraries for building interfaces and rendering shapes on screen make RoboFont a wonderful environment for invention, and the tool of choice for all the typeface designers at H&Co. Shown above, in color, are the tools’ best attempts to apply shading, based on the the designer’s inputs. The black outlines reflect manual adjustments after the fact, made to improve the appearance of this letter form.