New face soon to go on the Eileen Ford Modeling Agency head sheet is Gail Percy who hopes to break up her intensive Ph.D. program in anthropology at Berkely with modeling assignments. "It's a good creative release for me," says the daughter of Senator and Mrs. Charles Percy, "and a good way to get out from the pressure of graduate school. Gail thinks you can learn about people's customs through their clothes, worn not only for survival but ceremonial dress. "Balinese dancers are so restricted in their movement for their trance dance because of the restrictive nature of their clothing," she says. For herself, Gail chooses Gloria Vanderbilt jeans to wear every day, Anne Klein, sports-wear other times. She's also with the Grimme Agency in San Francisco, which encouraged her to enter the Virginia Slims contest for a sucessor to Cheryl Tiegs. She stayed in the running to the final 12.

We know a lot of T-shirt collectors. But do you know about the T-shirt freaks? The ones who will pay any price to get limited edition T-shirts from exclusive clubs or Hollywood film promos? Now the T-shirt freaks have set up their own network to tap the T-shirt market and provide a route to special editions like "Free Lee Marvin" shirts and the out-of-print "Pardon Patty" T-shirts.

The T-shirt trackers call themselves "The Society Handling the Interchange of Remarkable T-Shirts" (T.S.H.I.R.T.S.) and they have established a newsletter (The T-Shirt Quarterly) that's mainly a brochure for buying more shirts. Two-year subscription to the quarterly sheet is $9.95 and includes a copy of The Great American T-shirt and a membership in T-shirts international.

Organizer of T.S.H.I.R.T.S. is John Hall, once automotive history librarian for the Henry Ford Automotive Library, and advertising and marketing analyst among other things. He draws a similarity between his T-shirts and remaindered books or small edition books that have a special interest following.

Hall himself owns "only about 100 T-shirts-I live in a small place," he says.

Most expensive T-shirt in T-STQ is the Mommy Dearest ($16.95). "It's hand painted and hand slashed," says Hall, explaining it has been slashed to bring to mind "Joan Crawford's supposed tearing up of Christina's clothes that were not properly put away."

(T.S.H.I.R.T.S. is at 2210 Wilshire, Suite 165, Sta. Monica, Calif. 90403.)

It's such an international world of fashion that certainly, by clothes alone, you couldn't tell the French from the American guests at the French Embassy party Tuesday night. Taffeta and sequins was more the choice of the Americans while the French for the most part, stuck with simple, sleek lines such as Countess Isabella de Lasteyrie du Saillant, sister of the President of France, in a sheath of lipstick red chiffon by Guy Laroche. To be sure, anyone that night wearing turquoise eye shadow was American. The French were wearing far less make-up, and always in natural tones.

Ankle length dresses were worn by a few guests, but the evening before at a black tie dinner at the National Gallery, it was all long dresses, save one. Deeda Blair was wearing a printed chiffon tiered dress from Yves Saint Laurent and Evangeline Bruce was in a dress by local designer Anna Day Wallick.

Now it's hi-tech cosmetic cases. The models in Paris have turned in their swanky initialed cosmetic carryalls for the hi-tech variety and Washington models are starting to follow suit. Michele Paradise, a local model who worked at the Thierry Mugler and other Paris shows this season, has adopted the idea with a curler box from a discount drug store. Carolyn Kornemann, has switched her cosmetics to a fishing tackle box.

Paradise has pasted her blushers, lipglosses, and eyeshadows without their cases onto stiff cardboard "shelves" and uses the top tray meant for curler pins to hold her brushes, lipsticks and mascaras. She figures she carries about $250 worth in the box which cost her $3.

Kornemann, who picked up the box for $5.99 at Memco, has adjusted the compartments in her tackle box to fit the pencils and brushes in compartments meant for fishing hooks and weights.

Tired of the cut and color of an old pairs of pants? Woodies is taking trade-ins on pants next Saturday-maybe trade-offs is better word. If you turn in a pair of old slacks and buy a new pair of Haggar's, Woodies will donate your slacks to the SAJA Runaway House and Haggar Slacks will donate 50 cents to St. Jude Children's Hospital in Memphis. CAPTION: Picture 1, Deeda Blair; Top photo by Joe Heiberger; Picture 2, model Michele Paradise's curler-box makeup kit, above photo by Vanessa Barnes-The Washington Post.; Picture 3, Gail Percy, right.