"Dick Tracy" grosses fell by 31 percent in the film's second weekend, a respectable but inconclusive showing that leaves the future in question. Or maybe the picture fell by only 18 percent, a considerably better result that suggests it'll be a solid hit.

The confusion stems from the fact that the people at Walt Disney Studios want to have their cake and eat it too. Last week the studio refused to divulge how much of the $22.5 million "Tracy" gross had been earned at the movie's special midnight screenings, for which patrons had to buy $12 to $20 T-shirts to be admitted, because it didn't want anybody deducting the cost of the T-shirts from the total gross; after all, said Disney, a ticket is a ticket whether it's printed on paper or a cotton-polyester blend. But this week the studio suddenly announced that those special screenings took in $3.6 million -- and now it wants that total deducted from the opening weekend figures before the drop-off is calculated.

The Hollywood trade papers, for their part, ignored Disney's wishes and said the drop was 31 percent -- which is still the second-lowest of any major film released this year, behind "Teenage Mutant Ninja Turtles' " 26 percent drop. So far this summer, everything else has fallen by at least 35 percent. On a screen-by-screen basis, meanwhile, "Dick Tracy" also dropped by about a third, placing it behind "RoboCop 2" but ahead of everything else in per-screen average ...

High-Priced 'Instinct'

In the end, though, the folks who deal with money in Hollywood won't remember this as the week that "Dick Tracy" made $15.5 million -- they'll remember it as the week Carolco Pictures paid a record $3 million for a screenplay. Carolco is credited with driving up the prices paid to top actors by offering eight-figure sums to Sylvester Stallone for the likes of "Rambo 3"; now the company has broken new ground by outbidding all comers for a Joe Eszterhas script for a sexually charged thriller titled "Basic Instinct." The previous high price came two months ago, when the Geffen Co. paid $1.75 million for "The Last Boy Scout," a script from neophyte screenwriter Shane Black. The "Basic Instinct" script was sold less than 24 hours after it was submitted to various studios, in a fevered auction that reportedly involved six major studios and several independent companies ...

Knowing the Score

Hemdale Film Corp. has picked up the rights to "Impromptu," the directorial debut of James Lapine, the director and librettist of "Sunday in the Park With George" and "Into the Woods." The movie, which stars Judy Davis, Hugh Grant, Bernadette Peters and Mandy Patinkin, is loosely based on the love affair between composer Frederic Chopin and writer George Sand. It'll be released this Christmas ... Another veteran of the theatrical musical now making inroads into Hollywood is Andrew Lloyd Webber, who just signed a deal with Steven Spielberg to collaborate on a full-length, animated version of "Cats" for Universal Studios. Animation being the painstaking process that it is, Universal doesn't expect the movie to be completed for 18 to 24 months, so it'll be in theaters in late 1991 at the earliest. Lloyd Webber's more recent "Phantom of the Opera" is also in development at Warner Bros. with "Cousins" and "The Lost Boys" director Joel Schumacher ...

Short Takes

The motion picture ratings board handed out another X rating this week. This one went to "Frankenhooker," a horror comedy from director Frank Henenlotter. It's about a young man whose girlfriend is chopped up by a lawn mower, and who reassembles her using body parts from dismembered hookers ... And what must be the first festival devoted to Troma Inc. will take place in Washington this August, under the auspices of the American Film Institute. The retrospective, which comes to the AFI theater in the Kennedy Center on Aug. 9, will include screenings of "Class of Nuke 'Em High" and "Monster in the Closet," as well as the world premiere of "The Toxic Avenger III: The Last Temptation of Toxie."