Optical Sizes in Typography
Typefaces are usually made with a specific set of parameters in mind: how will it be used, within what medium, with ink or digital or both, and at what sizes? The best type creators get as specific as possible about those answers in order to formulate their best response. They create an answer to a problem we encounter often.
Optical sizes within a type family answer many of the questions about which circumstances require which weight of type. In printed material, many will use the book or regular weight for text and set it at around 10–13 points, depending on how they want it to look on the page. The smaller a text needs to be, the more oddities it will need to contain in order to be readable and to be recognized as belonging to a specific family.
Think of the caption weight of type. In order to still look like the text weight, the strokes need to be thicker, the serifs need to be more pronounced, and the little quirks that our mind recognizes as specific to that type family will need to be emphasized. But using the caption weight as text is quite jarring because the main thing we recognize is thicker, pronounced oddities not meant to be seen at larger sizes. It steals our attention. Matthew Carter’s Bell Centennial, for instance, works in phone books and where information is densely packed, but it is not elegant in headlines — not that it hasn’t been tried, it is just not elegant.
Optical sizes — the changes made to a typeface’s structure to account for our perception at different sizes — is such a big deal that it has even been capitalized upon to create type families. Take Vendetta, for example, made by John Downer in 2006. Vendetta is based on the irregularities of a person’s handwriting. It tries to convince us that we are looking at something scribbled on paper rather than pixelated on a screen. Its oddities work in its favor at small sizes, but become quite pronounced as the size is increased.
Now, the Vendetta example is not a strict optical size example, but it demonstrates how and why choosing the correct weight matters. In fact, choosing the right weight for your purposes comes second only to choosing the right typeface. Using Vendetta for the movie Lemony Snicket’s A Series of Unfortunate Events was perfect — a human feel, but a bit creepy and a bit off. And mixing the regular with the italics for each name added to the tension. Bell Centennial probably would have failed at that job, but so would have Helvetica and Mrs. Eaves and Futura. Vendetta matched the tone of the title art without dumbing it down it to a cartoonish level unbecoming of the title sequence. Choosing to use a caption weight for text brings down the entire project to a level unfit for professional typographic needs.
So make sure that after you pick just the right typeface, the right weight is also chosen. Keep pursuing the excellence within your reach.