A federal judge said yesterday that Howard University had violated federal civil rights laws and "the spirit of racial equality" by dismissing a white faculty member and then arguing that as a predominantly black institution it can "take race in consideration" in choosing its professors.

In a strongly worded opinion, U.S. District Court Judge John H. Pratt said the university had become "an apostate to the cause of racial equality" by suggesting it can give a preference to blacks that is contrary to the "very spirit . . . which has animated the civil rights movement" since the U.S. Supreme Court's landmark school desegregation decision of 1954.

"Ironically, many eminent leaders of the civil rights movement of the past half-century emanated from the halls of the Howard University," Pratt stated in a lengthy footnote, "which asks this court to abandon the 'colorblind' policies for which those leaders fought."

Pratt's ruling came in a race discrimination suit against Howard by Antonio Planells, 46, a white teacher of Spanish, who was an assistant professor at the university from 1976 to 1980. The decision, issued yesterday, follows a five-day nonjury trial in early May.

Pratt said he will hold a hearing July 11 on Planells' request for reinstatement and $1.4 million in damages. He ruled that Howard had given "disparate treatment" to white and black faculty in its Romance language department and had promoted black faculty members with lesser qualifications than Planells'.

Pratt said the university also had retaliated against Planells for being willing to testify in a grievance proceding on behalf of another dismissed white faculty member, Gabrielle Turgeon.

Pratt's comments in the footnote become part of the court record, but did not bear directly on the ruling in favor of Planells.

Henry Duvall, a spokesman for Howard, said university officials were not available to comment on the case.

Last week, U.S. District Court Judge Aubrey E. Robinson Jr. rejected Howard's request that he set aside a $60,000 jury verdict won by Turgeon. Howard had also contended in that case it could give preference to blacks, but Robinson said the argument was raised at the wrong time as a post-trial motion and rejected it without discussing its merits.

In earlier cases, Howard officials strongly denied any discrimination and said the employes it dismissed were ousted because of poor performance.

In the Planells case, the university filed a memorandum just before trial contending that black colleges have a "legally recognized unique status" and therefore are subject to a "different legal standard" under antidiscrimination laws.

Because of "past discrimination against blacks," Howard argued, there will be more whites than blacks with advanced degrees "for many years to come." Thus, it said, if black colleges were forced to adopt a color blind policy in hiring, "teaching opportunities for blacks in the total work force would be diminished."

Pratt rejoined that affirmative action programs with a preference for blacks are permitted only to remedy past discrimination. At Howard, he said, the Romance languages department had a 14-to-12 black majority when Plannels was hired, a balance that had shifted to 24 blacks and eight whites by 1981, though blacks hold less than 10 percent of the advanced degrees in the field.

Pratt added that rather than having fewer opportunities than whites for academic jobs, "employment opportunities for black academics are likely to be good relative to their white counterparts precisely because of their small number and because major universities are consciously seeking to increase the representation of blacks and other minorities on their faculties."

Planells was born in Argentina and holds a doctorate in Spanish-American literature from Catholic University. His attorney Bruce Fredrickson said Planells now lives in Taos, N.M., where he co-founded a private school.