Students noticed a new addition to their bathrooms and dining halls this September: posters reminding them to wash their hands. But the posters were not the familiar, cheery cartoon illustrations that dot the walls of Yale University Health Services, prompting passersby to cover their coughs and wash up. These were cheery in a different way.

“You’ve got trouble on your hands,” one version announced, showing a yellow handprint sprinkled with alien- and devil-faced “germs.”

“Happy birthday to you / Your hands are a zoo,” another read. “If you hum this while you wash them / They’ll be cleaner times two,” it continued, alluding to the commonly-cited Center for Disease Control guideline that people should wash their hands for as long as it takes to sing “Happy Birthday.”

A third was blazoned with the declaration, “Lady Macbeth got one thing right: Keep your hands clean,” next to a red hand with a small yellow dot labeled “Damn spot.”

The message was simple, but clear: Regular hand-washing can help to prevent the spread of swine flu and other diseases.

The man behind the signs, longtime Yale employee Patrick Lynch, has also designed many other visuals for the University. Working out of a Science Park office, a half-hour walk from the student dorms where his posters now hang, Lynch, 56, has observed changes at Yale through the lens of art and design for 37 years.

“It’s just sort of evolved over the years,” Lynch said of his career at Yale, which began in 1972 when his high school friend Phillip Simon recommended Lynch to his mother, who was then the medical illustrator at the School of Medicine.

And so, during his freshman year at Southern Connecticut State University, Lynch began working at Yale, photographing and drawing medical specimens. Years later, with the advent of computer graphics and audiovisual technology, he took charge of a succession of communications teams and began designing the user interfaces of Yale Web sites, including that of the Yale portal, which serves as a hub for the rest of Yale’s Web sites. All the while, Lynch pursued bachelor’s and master’s degrees in biology at SCSU. He has even served as a lecturer in radiology at the School of Medicine.

Lynch has been surprising his friends with his varied talents — including cooking and painting — since high school, said Simon, who is now the director of interactive communications graduate programs at Quinnipiac University. But as a young man, he especially liked to sketch wildlife, a skill that led him to change his major in college from fine art to biology.

“I was always interested in science,” Lynch said. “But I really just wanted to learn how to draw people.”

Anatomical drawings in pen and watercolor led to wildlife paintings and photography. Drawing on his degrees in biology, Lynch co-authored and illustrated “A Field Guide to North Atlantic Wildlife” in 2005 and a “Manual of Ornithology” in 1993, among other books.

But at Yale, Lynch’s work grew from illustrations by hand in the 1970s to computer illustration and HTML design, all self-taught, in the ’80s and ’90s.

“He is astonishingly versatile,” said Anne Murray-Randolph, his supervisor and the assistant vice president for strategic projects and communications. “He’s a writer and he can also conceptualize the presentation of projects.”

His work, if not Lynch himself, has been visible at Yale for years. Besides the clean hands posters, he designed a series of anti-phishing awareness posters for ITS that now hang in computer clusters around campus, and several awareness campaigns targeted at Yale staff — everything from educating people about the Y2K scare in 2000 to preparing staff for the transition to a new e-mail system in 2008.

All his posters are designed to catch the eye, Lynch said.

“People are so bathed in other media that you’re looking at various ways to pierce through a fog,” he said. “Sometimes it’s a beautiful image, sometimes it’s something that’s a little weird that gets you to look more closely at it.”

In the case of the clean hands posters, colorful handprints were a striking yet lighthearted way to convey the message, Director of Emergency Management Services Maria Bouffard said.

For students, as well, the posters were amusing and eye-catching.

Colin Watson ’10, on his way into the Berkeley College dining hall, said that he thought the signs’ color and “nerdy humor” might draw students to the otherwise “industrial” Purell dispensers.

“I think they’re hilarious,” Ben Watsky ’12 said. “I’m glad [the administration] decided to allow some lightheartedness into what is, at heart, a pretty serious issue.”

But School of Art graphic design critic Jessica Helfand ’82 ART ’89 said that though the concept of the posters was successful, they lacked sophistication. She wondered why Yale did not ask a graphic designer at the School of Art to make the signs.

“A real designer who is looking to do something provocative and memorable might have done something simpler, bolder and more sophisticated,” she said.

If Lynch’s work is not formally sophisticated, he at least adds a touch of humor to many of his poster projects — “he’s always been quite the wit,” Simon said — which Lynch said are designed to complement more complete information found on Web sites.

But designing posters is just one of Lynch’s skills. From Web sites and HTML guides to ornithology textbooks and anatomical illustrations, Lynch has subtly influenced many corners of the University, said Jane Livingston, a director of finance communications and planning.

“I can’t even imagine Yale without Pat,” she said.