Should I be concerned about optimal font size for a particular font

Question

I am aware that certain fonts, are designed for use at certain sizes, at least in the physical print world. They make uses of things like Ink Traps to prevent running.

With type for the digital world, I believe I have read that some OpenType fonts contain different glyphs for use at different sizes. (I might have imagined this). Also, do certain fonts have a certain size they look best at? If this is true, how can I find out what Sizes they are designed for use at? (I guess this would be in the OpenType meta data right?)

Answer 1

“Concerned” – not so much… “Aware” – definitely. The fact is that really good fonts should have shapes matched to their physical size. Simple scaling can't always do the trick, or rather: rarely can. Take, for example, Computer Modern. This font has variants intended for use at, among others, 6 and 11 points (AFAICR). Glyph shapes (especially proportion-wise) are dramatically different for them and for a good reason. If you'd try to scale 11 pt variant to 6 pt, you'd get glyphs a bit too narrow to be read comfortably. Similarly for 6 pt scaled up to 11 pt, you'd get too “heavy” and wide glyphs. These variants create a consistent typeface when used at the right sizes, yet they're different shapewise (much like italics or slanted versions are without “breaking out” of the typeface style).

Besides CM font, quite often one can see fonts with titling, heading, poster and so on variants. The thing is: most probably shape meant to be used in e.g. book main matter will look too aggressive / fat when used in headings. Something like a kid in too tight shorts. ;) This is not, of course, a certainty, but it is to be expected and close attention should be paid to it.

The bottom line is: specific size and use – specific shape. Good typographers, real craftsmen, know that. That's why really good fonts are designed with so many variants.

I'm not sure if OpenType allows one to specify explicitly which shape should be used at which size, but even so, one can “pack” many shapes in one .otf file and switch between them using the same abstraction used to determine if italic or bold variant should be used. It's all manual intervention, but still: achievable.

Answer 2

Ink traps are a device to compensate for over-absorbent papers and metal type in letterpress printing. They are mostly irrelevant for offset presses. James Felici has an excellent summary in "The Complete Manual of Typography" (highly recommended for anyone working with type). They are mostly irrelevant today, unless you are working on a letterpress project.

That aside, it definitely DOES make a difference which font you use at what type sizes.

Metal type, from its earliest days, was drawn and cast individually for every point size. A print shop might purchase a Caslon at 8, 10, 12, 16 and 24 points. Each character of each font was individually made. You are probably aware that characters in small sizes must be a drawn more heavily, relative to height, than at normal text sizes. Conversely, display sizes require lighter strokes and finer detail, particularly in serifs. They are not just a straight enlargement of the text design.

Better than 99% of digital text fonts are drawn for use at 12 points. As a result, they lack many nuances and fine detail at display sizes and are too light, and too tightly spaced, in tiny settings such as might be used for captions and footnotes. This was one of the trade-offs that came in with phototypesetting and was the rule in the early days (i.e., up to a very few years ago) of digital type. Hinting was a way to mitigate some of the issues created by raster-dot/character size problems on low resolution devices like laser printers, but it didn't address the fact that an outline drawn to look good at 12 points would not work well at 36 or 6 points.

The idea of Multiple Master fonts was that the font software contained different outlines that would be invoked for different sizes. It had some traction for a while, but hasn't proved workable and is fading out. TrueType Collections (.ttc) were another approach to the problem.

Display or "titling" faces, such as Trajan or Felix Titling, are specifically drawn for 24 point and up.

Today, several foundries produce OpenType versions of typefaces in a range of size-specific fonts, typically optimized at 6-8 point, 12 point, 16-18 point and 24 point, with names like Caption, Text, Subhead and Display. Using the appropriate font makes a big difference to the appearance of a typeset page. The Garamond Premier Pro family from Adobe, designed by Robert Slimbach over the course of many years, contains 39 fonts, covering several weights in each of the four size ranges, in both Roman and Italic faces, making it one of the most versatile and useful digital "classic" typefaces.

Advanced typesetting software can automatically switch to the correct optical font for the size specified, if the appropriate information is contained in the fonts themselves.

If you plan on setting a lot of type, you'll find that investing in the complete font families of a few "opticals" will be very worthwhile.