NWA-PCUG Newsletter Article, August 2010
A Font of Knowledge
By Dave Chrestenson, Member, Fox Valley PC Association, Illinois
May 2010 Issue, Fox Tales

deanholste at sbcglobal.net (click to email author)

Have you ever gotten a small print from your camera or cell phone and thought it looked pretty nice? And decided to have an 8x10 made? And discovered that diagonal lines stair stepped across the page and everything else looked like they were made of colored Legos? And realized why that happened? It’s because all pictures are made out of pixels, this is called bitmapped, and there were not enough pixels in your image. So, when it was enlarged, you saw the individual pixels. Now, try an experiment. Open Word (or your favorite word processor,) select Times New Roman, size 6 point, and put an “s” on a page. Now change the size to 60 point and put another “s” on the page next to it. Now add a third “s”, this time at 600 points. Now print the page out. Look Ma, no pixels! What happened? Why don’t characters pixilate also? Welcome to the wonderful, and confusing, world of typography. Let’s see why, and learn a bit about what’s going on.

First, a given character set, or typeface, is contained in a file and is called a font. Now, if you’ve ever thought about it, you probably assumed that there was a bitmap for each character in the font, and when you pressed a key the system found that bitmap and printed it. Not so easy. If that were the case you would get pixilation. And that was the way it was done, once upon a time, and there are a few cases where it is still useful. (I’ll get to those later.) Instead, each character is stored as a set of formulas, or equations. If you remember your analytic geometry you will know that any equation can be plotted as a line or curve. So, for a character, there is a set of equations, each of which defines a part of the outline or the character. A straight dash would be easy, four equations, one for each side. A dollar sign would be more complicated. When you key in a character the equations are adjusted to define the point size you specified, then the outline of the character is created, then it is filled with the color you selected. (For those seeking more enlightenment, Google “Bezier curves.”) But it gets a lot more complicated. For each character there is more than one set. Bold type is not just fat type, if so the “counters” (the little openings in letters like e and o) would get filled in. So the typographer has to design an entirely unique shape for each bold character, one that looks like the normal one, but is heavier. Italics? Same thing. Another design. Italic Bold. Yep, another design. And so on. And how many characters are there? Well, let’s see. There’s the 26 letters of the alphabet of course, 10 digits, and, say, 14 special characters. That’s fifty. But how about upper and lower case. Add another 26. Small caps. Another. But just 14 special characters? Did you know there are four different dashes? And points of ellipsis. And umlauts. And so on. In fact, one of the formats for storing fonts can contain more than a million characters, and it’s not uncommon for a well designed font to have over one thousand.

Back to you pressing a key. What happens? First, the character formulas are selected. Then a kerning table that’s also built into the font is read. This compares the character you selected with the character immediately before it. Certain combinations of characters have to be printed closer together or farther apart to look correct; this is the function of the kerning table. Next another table is checked. It’s been found that if exactly the same shape of character is printed in two different sizes they won’t look the same to the eye. So this table looks at the point size you selected and adjusts the character thickness appropriately. (Larger sizes are thinner and closer together.) Then a “hints” table is referred to. This is used when the character is going to a device with low resolution, such as a monitor. (It adds anti-aliasing to reduce the “threshold effect.”) It also makes adjustments to the character to make it display more legibly. Finally, after some more manipulation which I won’t take the space to go into here, your character appears somewhere.

Now, all of this is the responsibility of the font designer. And good ones take all of the above into consideration. It’s certainly possible to skip some of the above. Ever seen these CD’s “Thousand’s of fonts for $29.95?” I seriously doubt that they’ve put much time into each of the above factors. You get what you pay for.

And lastly, I had mentioned above that there are still a few bitmapped fonts around. Why? Because regular fonts, no matter how well designed, have problems with legibility when displayed at small sizes on a monitor. This is a common problem in web design. Bit-mapped fonts are specifically designed for this purpose. So, the next time you key in “Dear Sirs,” take a few seconds to think and appreciate the over-worked, under-appreciated font designer who spent many sleepless hours to let you make your document look pretty.

Still curious? There are many books on the subject; the one to start with is “The Complete Manual of Typography” by James Felici.

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