ROBYN COSIO painted two delicate but distinct eyebrows onto the rather blank countenance of Natalia Campagne, a 28-year-old high-end matchmaker, at the Peter Coppola Salon on Madison Avenue the other day. Ms. Campagne has long blond hair and a piquant, heart-shaped face, and with a flick of Ms. Cosio's brush, expression flooded her pale features.

Ms. Campagne smiled and ducked her head, ceding her chair to Lia Sanfilippo, 37, a middle school teacher and personal trainer whose own eyebrows were dark circumflexes above deep brown eyes. Seven minutes later, the chair swiveled again -- a pivoting gallery of new faces, six women each hour, who pay $50 and a gratuity for Ms. Cosio's time.

Ms. Cosio calls herself an eyebrow specialist; it's a term and a market niche unheard of until a few years ago. As quickly as plastic surgeons and Botox mania are erasing the expressions from millions of faces each year, eyebrow -- what to call them? -- technicians are painting them back on. You can live like a character in a Roy Lichtenstein panel: stencils made by Bliss come in three widths, to color you surprised, ironic or intent. Or you might try stencil kits of movie star eyebrows -- like those of Gwyneth Paltrow, Heather Locklear and Lisa Kudrow -- from Eyebrowz.com.

A biopic of the possessor of some of most famous eyebrows of all time, the painter Frida Kahlo, is being shot now in Mexico City. The film, ''Frida,'' stars Salma Hayek, who sports a vivid unibrow for her title role. ''I think she'll bring the unibrow back into vogue, because it looks so amazing,'' said a spokeswoman for Miramax, the film's distributor.