Although Congress put a 4 percent limit on federal pay raises this year, the committee that controls the Government Printing Office has ordered a 3 percent retroactive raise for 2,700 GPO craft union workers, with the prospect of an additional 2 percent just before Christmas.

The pay vote by the Joint Congressional Committee on Printing could mean more than 15 percent over three years. It is a compromise between the two-year, 20 percent pact unions wanted and the 22 percent pay cut their boss proposed to whittle workers down, he said, to rates paid in other government agencies.

Last week the Senate-House group, headed by Sen. Charles McC. Mathias (R-Md.), unanimously ordered that the raise be made retroactive to June 18 for compositors, machinists and other craft workers. Their special contract with Uncle Sam expired in June.

This December, the committee said, GPO workers can get cost-of-living adjustments of up to 2 percent (based on the local inflation rate for the period March to September 1982). They may also have COLAs up to 5 percent in June 1983, and June 1984.

GPO is part of the legislative branch of government. Salaries for union workers are controlled by a 60-year-old law. It gives the committee authority to set wages, regardless of what Congress does for the rest of the federal work force or other GPO workers.

Because of its unique job -- overnight production of the Congressional Record and Federal Register, thick, technical magazines with a small but influential circulation -- GPO pay scales are higher than for feds with the same job titles in other agencies. Backers say this is because of the heavy volume of deadline work not expected or required of other U.S. blue collar workers.

GPO chief Danford L. Sawyer Jr. has argued, unsuccessfully, that a lot of GPO's work could be done better, cheaper, on the outside.

He has had many unkind things to say about the relationship between GPO unions and members of the Joint Committee which, he says, has resulted in "bloated" pay scales and production costs at GPO.

The committee, clearly, did not agree, and it has told GPO to crank out those retroactive paychecks as soon as possible.