TWO RECENTLY signed production deals -- one coming fast on the heels of the other--have signaled a turning point in Hollywood's racial calculations. The agreements, with Richard Pryor and Eddie Murphy, show that the business has acknowledged that it can accommodate more than one black box-office star at a time.

Pryor signed a five-year "production arrangement" with Columbia Pictures, whereby he got $40 million for his own newly formed production company. In exchange, he agreed to star in at least three "major" Columbia releases and to produce four "moderately budgeted pictures."

Soon afterward, Paramount Pictures announced that a similarly auspicious deal had been struck with Murphy, the hottest new draw in the movies. In this case Paramount agreed to bankroll a newly formed company called Eddie Murphy Productions for an undisclosed amount and to pay the young star a rumored $15 million for exclusive services to his next five pictures. The financial package was further sweetened by offering Murphy a share of the distributor's gross.

These curiously coincidental deals consolidated relationships that have proved mutually satisfying and profitable. The No. 2 and No. 4 box-office attractions of the Christmas season were "48 Hrs.," which introduced Murphy to film audiences, and "The Toy," which starred Pryor. This summer Murphy and Pryor are represented by the No. 3 and 4 grossers, "Trading Places" and "Superman III," respectively.

In Hollywood, more than in other places, money talks.

In the 1960s Sidney Poitier demonstrated that a black leading man could emerge as a bankable star--indeed, the top draw in the country during 1967-68. However, in his autobiography, "This Life," Poitier speculated that one black star might have been unconsciously regarded as The Limit. In connection with the unfulfilled screen acting career of his friend Ivan Dixon, Poitier wrote, "Ivan was a truly talented actor whose potential was never realized. Part of it was his own fault and part of it was the industry's fault--the industry wasn't ready to cultivate two of us at the same time, nor did it have the psychological wherewithal to absorb two of us at the same time. Yet--had he been more of a tough, hard-driving, go-getter personality accustomed to smashing down doors, the industry might have--just might have--looked up and paid more attention."

Pryor and Murphy are now in a position to establish a fresh precedent, and perhaps it allows for more leverage and flexibility than Poitier's heroic, ultrarespectable example. Being comedians, Pryor and Murphy suggest rowdier movie identities and possibilities; the fact that they belong to different generations and have dissimilar performing styles would also seem to leave more options open for black performers still seeking a Hollywood break. (Coincidentally, both of them will appear in Washington in the coming weeks.)

At the very least their new eminence in the Hollywood scheme of things has probably reversed the policy of guarded neglect that evolved after the black exploitation genre finally croaked in the mid-'70s and then "The Wiz" failed to justify its $25 million production cost. These more or less simultaneous collapses led to the conclusion that there was no longer a definable black moviegoing public that needed to be served, even with sleazo action melodramas.

The reputable major studio projects dominated by black performers--"Lady Sings the Blues," "Sounder," "The Bingo Long Traveling All-Stars and Motor Kings," "Uptown Saturday Night," "Let's Do It Again," "Sparkle," "The Wiz"--went out of fashion and out of consideration, obliging the actors to fall back wherever they could on featured or perhaps costarring roles in movies with white stars. Poitier's book documents the precarious margin of success enjoyed by his two popular comedies with Bill Cosby, "Uptown Saturday Night" and "Let's Do It Again." The former, made for less than $3 million, grossed better than $8 million from a predominantly black patronage. The latter, slightly more costly, returned $15 million after attracting a considerable "crossover" business from white moviegoers.

"In the context of the business as I understand it," Poitier concluded, "the black filmmaker is inescapably dependent to some extent on the white audience if he is to reach . . . break-even point with an average film."

Black actors who entertain mass-audience aspirations--and why shouldn't they in this movie-rich culture?--face daunting odds that must be confronted and somehow finessed. A major film career may be impossible if a black performer or director appeals exclusively to a black moviegoing public. The economic base is simply too lean to provide a comfortable margin for error. Perhaps a third of the population supports the movies to begin with, but the white percentage still outnumbers the black by a 10-to-1 ratio.

Opportunities of any sort had declined so severely since the mid-'70s that there was talk early last summer of a possible NAACP boycott of one or two of the major distributors. It didn't materialize, although the Directors Guild did file a discriminatory suit against Warner Bros. last week on behalf of its minority and female membership. Now the prominence of Pryor and Murphy, added to Louis Gossett Jr.'s Academy Award for "An Officer and a Gentleman," makes the situation look more promising for black actors. At the moment it's the actresses who remain shamefully deprived.

The boycott proposal was motivated to some extent by an embarrassing aspect of the NAACP's 1981 "Image" awards, in which only a single candidate, Cicely Tyson in "Bustin' Loose," could be nominated for the best actress category. The selection process remains just as desperate today, so a special incentive would seem to exist for lobbying on behalf of the actresses.

PRYOR AND Murphy have maneuvered into their bankable positions by taking advantage of this discouraging interlude, with the opportunities largely confined to sidekick roles. Considered unreliable--no doubt with plenty of justification--for several years, Pryor was denied the sassy starring showcase Mel Brooks envisioned for him in "Blazing Saddles," which Pryor helped write.

Pryor gained his mass audience foothold playing a reluctant, dismayed accomplice to Gene Wilder's whimsically intrepid comic hero in "The Silver Streak." The foothold was secured when he elaborated the same role in the enormously successful "Stir Crazy." One of the curiosities of Pryor's career is that he still hasn't found a fictional role, comic or dramatic or in-between, that utilizes his talents to the utmost, although he's flirted with affecting characterizations in "Lady Sings the Blues," "Bingo Long" and "Blue Collar."

However, Pryor may not require an inspired starring role, desirable as that would be, since he's made an indelible emotional impact in another format and in real life itself. Pryor's expressive breakthrough as a movie star came in the concert film he made in 1979. It was verified by the second one-man show released in 1982, a triumphant comeback appearance from the brink of death. Performing comic monologues before live theater audiences, Pryor has risen to greatness, refining a passionate set of confessions, jokes and reflections into profoundly stirring material. Hiding nothing prejudicial and sparing himself nothing emotionally, Pryor exposes the unconscious of one brilliant, troubled funnyman, and this unconscious turns out to speak directly to millions of turbulent modern psyches.

Pryor's movie plans seem to be spelled out for the immediate future. He'll be doing a remake of the great Laurel & Hardy short "The Music Box" with Burt Reynolds; and the Columbia deal mentioned three specific projects--a biographical drama about Charlie Parker; "The Man Who Would Work Miracles," which presumably derives from H.G. Wells' classic comic fantasy "The Man Who Could Work Miracles," originally filmed in 1937; and a Gene Wilder script tentatively known as "Double Whoopee" or maybe "All Day Suckers," intended to reunite the costars of "Stir Crazy."

We still lack even tentative titles from the Murphy brain trust, so the speculation surrounding his next moves remains tantalizing. Only 21 when he began shooting "48 Hrs." last summer, Murphy has certainly "made it" faster than any comic star in the annals of the medium, barring Charlie Chaplin, who started at 24.

Murphy's instant success has generated staggering financial rewards. Paramount evidently agreed to subsidize his production company and pay him $1 million for "Trading Places" on the basis of rushes from "48 Hrs." Approaching his third movie, Murphy already commands a salary of $3 million plus a percentage of the gross. This may still leave him shy of the $5 million or more reached by stars like Pryor and Reynolds in the present Hollywood economy, but then they've been paying dues and climbing to the top in the traditionally dogged, hit-and-miss, time-consuming ways.

"48 Hrs." was set up for Nick Nolte to run bruising comic interference for Murphy, the quick and incisive new finesse artist. The contrasts between Nolte's hulking, bad-tempered detective, Jack Cates, and Murphy's dapper, witty felon, Reggie Hammond, veer close to cartoon exaggeration, but they worked--and almost exclusively to the newcomer's professional advantage. He got to look better in every respect, wardrobe included. Nolte, the established box-office component in the package, ended up taking flak for looking rummier than many fans preferred. He seems to have made the picture's chemistry possible at some cost to his own following.

Having proved himself with undeniable distinction in "48 Hrs.," Murphy gained prompt costarring parity with Dan Aykroyd in "Trading Places," confirming his precocious comic authority and remarkable camera presence. Not that the role provided Murphy with a significantly enhanced showcase; in fact, it once again presented him in the facetious disguise of a squalid crook, Billy Ray Valentine, who becomes a dynamite junior executive soon after being liberated from the low-life trade of panhandling. This vehicle confirms the impression that Murphy is a natural, blessed with a spontaneous sense of timing and a rare ability to create funny, conspiratorial contact with the audience without losing it with coplayers.

MURPHY SEEMS far more at ease with the camera after only two movies than Richard Pryor may ever be. I've never felt that Pryor was comfortable with the camera's scrutiny. Some performers seem to know where they stand with this observant intruder and use it to their advantage. Murphy obviously belongs to that group. Physically, he's already a streamlined camera subject, as trim and compact as Chaplin, and he even has certain traits that recall Chaplin, like the amusing rhythmic saunter with which he descends the jailhouse steps in "Trading Places," adjusting his ragged costume on the way down.

I think Pryor affects you in spite of his awkwardness and because of his overwhelming vulnerability. In the concert films it scarcely matters if he modulates his effects for the camera, because he's connecting with a live audience and taking you into uncharted emotional byways. Murphy may start off with a significant technical edge on Pryor when it comes to comic acting for the screen, but he hasn't begun to formulate an identity or accumulate a history that can equal Pryor's for evoking powerful feelings.

When Pryor launches into a reflection like the following--"Racism is a bitch; it's hard enough being a human being, but here's another element added to it, and it's enough to drive you crazy"--the sentiment is uniquely validated by his presence and biography. Pryor's miraculous escape from death after nearly incinerating himself has given an almost religious dimension to his comic poignance; you can't suppress the irrational thought that he's survived his brushes with oblivion for a reason, perhaps to bear witness to the consequences of self-destructive impulses.

All of which leaves the precocious Murphy with a historic opportunity to make a difference or come up short. That fabulous contract has to be something of a burden, since it contains an unstated challenge: Okay, smart stuff, now show us what you can really do. Murphy's next film project hasn't been announced, but Washington fans can sample his stand-up act in concert appearances scheduled for Constitution Hall Aug. 17 and 18, backed up by The Busboys, the rock group featured in "48 Hrs." Pryor will be at Constitution Hall tomorrow and Tuesday, so the two appearances offer one of those rare, memorable comparative spectacles.

I haven't the slightest idea what Hollywood envisions for Eddie Murphy or what he envisions for himself. However, he can scarcely go on portraying petty criminals, no matter how likable. Now an established attraction, he's obliged to operate out in the open, at the center of his own comic vehicles. While it might be shrewd to share the performing burden, he will still be held responsible if his next comedies happen to misfire. Instant success cancels out the luxury of failure.

At any rate, it's important that he capitalize on this spectacular start. The worst thing he could do is provide Hollywood with another flimsy excuse for squandering a refreshing pool of black talent.