The National Council on the Arts met yesterday under a shroud of secrecy to tailor the programs of the National Endowment for the Arts to the 50-percent reduction that President Reagan has requested.

No artistic program will be left untouched, and most of them will suffer 40- to 50-percent cuts, according to NEA sources, to comply with Reagan's proposed budget of $88 million for NEA, reduced from the $175 million proposed in President Carter's fiscal 1982 budget.

NEA staff had prepared a tentative budget to accomodate the cutbacks, and the council, which advises the NEA, yesterday made recommendations on those figures. Council debate is required before NEA Chairman Livingston Biddle can send a detailed budget to Congress later this month. Once it is submitted, Congress can modify the budget, and some congressmen are optimistic that the funding will not be cut severely as proposed.

Biddle said yesterday that program funds -- which make up about four-fifths of the current NEA budget -- would be allocated $57.8 million. Administration would be given $12.7 million, and treasury funds (which are used for matching grants to major arts institutions) would receive $15 million. uChallenge grants would be funded at $2.5 million (down from $13.4 million in the current fiscal year).

Among programs which would suffer the largest cuts are the media arts program, the challenge grant program and the Office of Federal-State Partnership (which distributes the state block grants) -- all of which would be cut more than 50 percent. However, sources said yesterday, council members appeared to favor restoring some funds to media arts if Congress does not cut the NEA budget as deeply as the Reagan administration wishes.

Some programs that the NEA staff had proposed for outright elimination were restored by the council -- if only in token amounts to keep them in the budget. Among them are the Artists-in-Education program (budgeted for $5 million this year, restored at about $200,000); the International Program and the advancement grants program -- which awards 3-to-1 matching grants to developing organizations. Council members expressed strong support for the Expansion Arts program, which awards grants to smaller, up-and-coming arts organizations and is seen as a significant helping hand for minority arts groups. Expansion Arts will be cut by 40 to 50 percent.

Yesterday's meeting was announced in the Federal Register, as required by law for all federal agencies, but it was closed to all but council members and NEA program directors clutching thick notebooks of proposals to deal with the cuts. "Our black book," said one staffer.

Robert Wade, general counsel for NEA, said the reasons for closing the meeting could be found in OMB Circular A-10 which governs agencies dealing with budget material not yet submitted by the president to Congress. "We're not supposed to discuss budget until the White House discusses it and discloses it [to Congress]," said Wade.

However, the White House sent the budget to Congress yesterday at about 10 a.m. "If [the budget has] been made public, then the rationale is section 9b of the Government in the Sunshine Act," said Wade. According to the act, an agency cannot disclose anything that would "significantly frustrate implementation of a proposed agency action."

That rule is appropriate because to make detailed disclosures would frustrate our ability to deal with the congressional committees. They asked us not to disclose the budget figures until the members get them," said Wade.

A House Appropriations Committee staff member commented that although Congress did not want the budget figures disclosed in detail before the committee members received them, "I feel a little uncomfortable with [the NEA] invoking us" as an excuse for closing the council meeting to the public.