Good typog­ra­phy rein­forces the goals of the text.

Almost all texts com­mu­ni­cate a set of points (Sum­mary judg­ment should be denied for three rea­sons). Some­times a text also needs to instruct the reader (Add lines 7 through 21 and enter the total here). Other texts offer warn­ings or admo­ni­tions (You must be 48 inches tall to ride; Speed limit 75). In every case, good typog­ra­phy sup­ports and rein­forces the mes­sage.

Good typog­ra­phy is mea­sured on a util­i­tar­ian yard­stick. Typog­ra­phy that is aes­thet­i­cally pleas­ant, but that doesn’t rein­force the goals of the text, is a fail­ure. Typog­ra­phy that rein­forces the goals of the text, even if aes­thet­i­cally unpleas­ant, is a suc­cess.

Does that mean that effec­tive typog­ra­phy can be ugly? Sure. Some­times ugly is bet­ter than pretty. Look at the high­way signs again.

The script font used on the sec­ond sign could be called “pret­tier” than the stan­dard highway-signage font. But a high­way sign has a spe­cial pur­pose: it’s meant to be read quickly, from long dis­tances, at odd angles, and under vari­able light­ing and weather con­di­tions. The highway-signage font stays leg­i­ble under all these con­di­tions. It con­sti­tutes good typog­ra­phy because it sup­ports the goals of the sign.

The script font may be pret­tier, but in this con­text, it’s bad typog­ra­phy, because it’s not suited to the task. Con­versely, the highway-signage font would look ter­ri­ble on a wed­ding invi­ta­tion, where the script font would be appro­pri­ate.