Step 2 to effective large-format graphics: Font Size

Last month, I wrote about the virtues of keeping your large-format banners legible by making your message short and sweet. After all, our Three Second Rule states that if you can't visually pique the interest of your audience within three seconds, you lost the sale. Still, even with a power-packed short message on your graphic, it won't do a bit of good if your text is too small to read.

a BIG Billboard illustrating text & font size - is your text big enough?

Tip 2: Size your text correctly. Keep fonts large enough to be legible.

Most large-format graphics are glimpsed at from a distance, behind the wheel of a car, or even in the peripheral vision of sidewalk pedestrians. In some cases, the Three Second Rule is stretching it. More often than not, given people’s frantic lives, if text can’t be read easily, your audience won’t even bother trying. So, why would anyone make their graphics more difficult to read? Believe it or not, some people inadvertently do, especially by making their fonts too small. This simple calculation will help you size your fonts correctly:
  • Height of text (in inches) = 0.035 x Distance (in feet)
  • Point size of text = 72 x Height of text (in inches)
So, if you know your text is going to be seen from 20 feet away, such as across a walkway to a storefront window, then you’d do well to make your smallest text at least 0.7 inch tall, or a point size of 50.4. We've already done some of the thinkwork and rustled up a bunch of standard distances, listed below:

Distance Text height Point size
15’ 0.525” 37.8pt
15’ 0.525" 37.8 pt.
20’ 0.7” 50.4 pt.
30’ 1.05” 75.6 pt.
50’ 1.75” 126 pt.
100’ 3.5” 252 pt.
500’ 17.5” 1,260 pt.
1,000’ 35” 2,520 pt.

Height of text (in inches) = 0.035 x Distance (in feet)
Point size of text = 72 x Height of text (in inches)

Worth noting here is that, as of Adobe Illustrator CS2, the maximum point size of text is 1,296 pt., which limits you to a sight distance of 514 feet. Here at BIG Images, we've gotten around this by Creating Outlines of the text (cmd-shift-O or ctrl-shift-O for Windows users) and then manually scaling the resulting object. With this solution, make sure you have Rulers turned on (cmd-R or ctrl-R for Windows) and keep an eye on the resulting size in inches.

Consider this as well: your computers default leading (the space between lines of text, rhymes with “heading”) applies mostly to text set on small letter-sized pages. So, when designing for large format, the default leading (120% the point size of the font) doesn’t quite work out. In most cases, you’ll want to decrease it to 110% or even less, but just remember, there's no substitute for actually looking at your piece and adjusting it to what just feels right. If possible, create a mock-up with your own desktop printer on normal letter-sized paper and actually test it out at certain distances. All you really need is a few letters or two lines of text, just enough to check if your typography is legible.

Oh, and don't be afraid to call up your printer and ask them a few questions. They tend to be pretty knowledgeable about this sort of stuff.

Read Ben’s Step 3 to effective large-format graphics: Contrast is your best friend
Read Ben’s Step 1 to effective large-format graphics: Text length

Ben Lawless is rather wiry. Still, though, with his dashing good looks, you'd definitely be able to see him from at least 1,000 feet away.