It Takes Preparation
Much of hand lettering comes down to planning and setup. The actual construction of the letters should come quite naturally once the proper guide lines have been spaced out on the paper. Since type requires precise measuring, use the side of your ruler that measures points.
There are 72 points in an inch. The increments are much smaller and, therefore, more appropriate in measuring small text. It's much easier to say that the type in your newspaper is about 8.5 points than to say it's not quite 4/32 of an inch (0.11806 inches).
Lettering in All Caps
You will rarely see lowercase lettering in a comic. Lowercase lettering involves measuring many more guide lines than uppercase lettering does, and few working cartoonists have the time to devote to such detail. You will notice that most comic strips and comic books feature typography involving capital letters only. This is called working in “all caps.”
Capital letters also allow for a wider range of humor. For example, a proper noun (the name of a particular person, place, or thing) would normally stand out because it gets capitalized. In all caps, it can be disguised.
In this cartoon, “Irony” is a disguised proper noun.
Measuring Lettering Guides
To measure guides for lettering, you need to indicate the height of the letters and the space between lines of text (called “leading”). First, draw a horizontal line a comfortable distance — about 6 to 8 points — from the upper boundary of your image. Type that runs too closely to the borders of your comic will be difficult to read. For the same reason, leave the same 6-to 8-point margin from the left and right borders. If you're lettering 12-point type, the second horizontal line will come 12 points below the first. Between these two lines, your first line of type will be lettered.
A common typographical rule of thumb is to calculate leading as 20 percent of the type size. For 12-point lettering, that's about 2.5 points. The third line is drawn 2.5 points below the second. This third line, besides indicating the leading, is also the top line for the next row of text. A fourth line is drawn 12 points down, and a fifth is drawn 2.5 below that. The result is a grid onto which you can letter the text of your comic.
Remember that most cartoonists work about twice the size that the final art will appear in. So, 12-point text will actually translate to 6-point. It's not advisable to letter smaller than that.
You may wish to build a lettering grid on your computer and print out a master copy. When you're ready to letter your comic, you can place the guide under your illustration board on your light box. The light box will enable you to see the grid through the board, allowing you to letter the comic without measuring lines over and over again.