More on optical scaling

My last post (4/23) explained that some digital type designers today are interested in the way Morris Benton’s fonts, and indeed all the metal types produced by the American Type Foundry in the early 1900s, were optically scaled. Optical scaling was easily accomplished at ATF by adjusting certain settings on Linn Boyd Benton’s matrix engraving machine. Linn Boyd Benton explained in an essay he wrote in about 1906:

The adjustments are such that the operator is enabled to engrave the letter proportionately more extended or condensed, and lighter or heavier in face, than the pattern. All these variations are necessary for the production of a properly graded modern series containing the usual sizes. In fact, on account of the laws of optics, which cannot be gone into here, only one size of a series is cut in absolutely exact proportion to the patterns.

The illustration of optical scaling reproduced below was made in 1989 by ATF’s successor, the Kingsley/ATF Type Corporation. At the time, Kingsley/ATF was embarking on a program of digitizing typefaces, including the optical scaling characteristics of the original metal types. Ultimately, the company went bankrupt in the early 1990s, but that’s another story.

The illustration uses the capital M from Morris Benton’s Wedding Text, designed in about 1901. In the earlier “metal type” days at ATF, the set of Wedding Text patterns, one image for each letter (these particular patterns, by the way, are now part of RIT’s Benton Collection), were used to produce matrices for every type size. According to the handwritten “daybook” of general engraving machine settings for cutting the matrices for 228 ATF typefaces, no size of Wedding Text was cut exactly proportional to the pattern. Instead, the matrices for each type size were either condensed or expanded in relation to the pattern. (In most other typefaces, one size, usually somewhere in the middle of the range of sizes for that face, was “normal,” i.e., the letters were cut exactly proportional to the images on the patterns, not condensed or expanded.)

To generate this illustration, Kingsley/ATF photographically enlarged these three sizes of a Wedding Text capital M to a uniform height, so that customers could then easily compare them. Notice that the smaller the size, the more expanded the character. This is necessary simply for legibility, although in the days of metal type mechanical parameters also dictated that smaller sizes be expanded.

In addition to the expansion or condensation of the letter, the “set width” of letters in different sizes also had to be adjusted for good optical scaling. The set width is the total amount of horizontal space (width) on a piece of metal type. In order for the eye to be able to read very small type, more white space is needed around each letter, so the type needs to be relatively wide.

Kingsley/ATF produced the following illustration, also in 1989, to show its customers this aspect of optical scaling. Because enlarging this sample will perhaps also distort it, I’ve left it at its original size; I apologize for the very small 6-point example. But hopefully it is understandable. I’ve re-typed the Kingsley/ATF caption to this illustration below it in case the original caption is too small to decipher.

Kingsley/ATF’s original caption: “Notice the difference between a true 6-point type enlarged to 24 points and a true 24-point type. The true sizes were created using Optical Scaling. Typeface: Wedding Text”

More later …

Advertisements

One response to “More on optical scaling

  1. Brilliant. I’ve never seen this piece of literature put out by Kingley/ATF but it is a principle I’ve been trying to hammer into every graphic designer/student who tours through the studio. The difference of the page “color” and legibility of the face and composition is dramatic when comparing foundry type to it’s contemporary digital version reproduced photomechanically for letterpress or offset printing.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s