Selecting Fonts

Text
Font Readability Study

by Dr. Ralph Wilson

In February 2001 readers
patiently answered survey after survey to help determine what they
considered the most readable fonts and sizes for HTML e-mail. While this may
come as no surprise to you, it is causing me to change my standards.

Readability between Serif and Sans Serif

Common wisdom developed
over centuries is that serifs, the little horizontal lines at the tops and
bottoms of characters, make text easier to read. That is why nearly all
books, magazines, and newspapers use a serif font such as Times New Roman or
Bookman. The fallacy, however, is the assumption that serif fonts are easier
to read in any medium. In fact, the computer screen is a much different
medium than the printed page. The resolution is much less, about 72 dots per
inch (dpi) for the computer screen vs. 180 dpi or 300 dpi or even higher for
printed matter.

We conducted two
separate surveys with serif typefaces. First we compared Times New Roman 12
pt., the default for many Web browsers, with Arial 12 pt.

I was a bit shocked by
the 2 to 1 results, since I had been led to believe that serif fonts were
more readable. In the next test I compared two serif fonts, and gave viewers
an option “could not distinguish between the two.”

This time I didn’t
identify the typeface by name, but only by letter so people didn’t
necessarily know what face they were seeing. I compared Times New Roman 12
pt. with Georgia 12 pt., a serif typeface developed by Microsoft especially
for screen readability. However, my results showed that Georgia is not
available on as many computers as Times New Roman or Arial, since the “could
not distinguish” response was significant.

While Georgia seemed to
be substantially more readable than Times New Roman, the number of users
that did not have Georgia font installed on their computer seemed to be
significant at 15%. And since Arial was strongly preferred over Times New
Roman, I moved to examining the readability of Sans Serif fonts.

Readability of Sans Serif Fonts

Another font that
Microsoft developed to increase screen readability is Verdana, and it seems
to be much more widespread among computer users, even Mac users, than
Georgia. My first test pitted Arial 12 pt against Verdana 12 pt.

Verdana has a much more
open letter and takes up more space than Arial, which contributes to its
readability, but at 12 pt. respondents still showed some preference for
Arial (53%) over Verdana (43%). The fact that only 4% couldn’t distinguish
between the two indicated that both fonts are widely installed on computers.

Size and Readability of Sans Serif Fonts

Finally, I tested
readability vs. size for Arial vs. Verdana, and came up with an interesting
result.

I also asked respondents
which sizes of Arial and Verdana were “too large” for body text type and
“too small” for body text type. These were the answers:

Both approaches showed
the same conclusion. At the 12 point size, Arial is preferred for
readability 6 to 4, while two-thirds of respondents see Verdana 12 pt. as
too large for body text. But at 10 pt. and below, the readability preference
shifts to Verdana. At 10 pt. Verdana is preferred over Arial for readability
2 to 1. And at 9 pt. Verdana is preferred over Arial for readability by a 3
to 1 margin.

The study seems to
indicate that a newsletter set in Verdana 10 pt. is considered “not too
small” by 93% of readers. Verdana 9 pt., however, is considered too small
for body text by two-thirds of the respondents.

Conclusions

Readers clearly prefer
sans serif fonts to serif fonts for body text. Therefore, in HTML e-mail
newsletters — and on my websites — I am moving toward 12 pt. Arial for
body text, and Verdana for 10 pt. and 9 p. fonts. I haven’t done adequate
studies comparing Georgia against Verdana for readability, but since Georgia
isn’t as widely installed as Verdana, I plan to stick with Verdana. For
headlines I’ll continue to use larger bold Verdana fonts.