Showroom glass gets read from two places: inside, by someone standing next to it, and outside, by someone in the parking lot or driving past. The second reader is farther away, and the message is built for them.
An inch for every 30 feet
Sign research puts readable lettering at about an inch of letter height for every 30 feet, in good conditions. A shopper across a 90-foot lot needs letters about three inches tall at the very least; at the real-traffic rate of about 20 feet per inch, closer to four and a half.
Leave the glass room
Sign-industry guidance keeps lettering to about 40% of the face. On a window, the open glass around the words is what lets them read from the lot.
Clutter costs distance
In one traffic-sign study, visual clutter nearly halved the distance at which drivers spotted a sign, from 110 feet to 60. We read that as a reason to give each run of glass one message, and to let the store’s own line be the one that reads from the street.
What we check before it prints
- The reading distance: where the shopper stands, and how far that is from the glass.
- The rules: depending on the municipality, some buildings can cover only part of their windows, some all of it, and some none.
- The view out: perforated film lets the people inside see out while the outside reads as one picture.
On the glass. Printed vinyl, perforated film, frost and cling, fitted to the panes you have.
Sources
United States Sign Council, Sign Legibility Rules of Thumb (Bertucci, 2006): an inch of letter height per 30 feet (pp. 5–7), lettering at about 40% of the face (pp. 8–9).
Garvey & Crawford, On-Premise Sign Research Review, Sign Research Foundation: readable distance in real traffic (p. 5).
Bullough, Illuminated Sign Conspicuity, Lighting Research Center (RPI) for the Sign Research Foundation: clutter and detection distance, citing a 1996 study (p. 18).
More Field Notes
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The clocks fall back on November 1
Signs read almost twice as far by day as by night. What that changes in the fall and winter graphics we print.
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Letters sized for the drive aisle
How tall the letters on a windshield banner need to be, and the sign research behind the sizes.
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Contrast beats color
Why the key word on our designs sits on the plainest, highest-contrast ground, and what a border is for.