A "press conference" held by Harvard personnel officers yesterday turned at times into a shouting match between the administrators and some 50 students who came to protest one of the University's employment practices.

The students demanded a change in Harvard's system of dividing its painting crews into "painters helpers" and "journeyman painters." The helpers get from 43c to 86c less per hour than the journeymen because-according to the University-they are still learning the skills of the trade.

About 75 SDS members voted last night to stage a non-obstructive sit-in in Dean May's office today in support of the workers demands and another demand that the Cambridge Project be stopped.

The sit-in, which will follow a 1 p.m. rally outside University Hall, will last until 5 p.m. when, SDS members said, they will decide whether to stay through the night.

But the students-repeating arguments made in SDS statements early in the week-accused Harvard of "racism" and "oppression of black and white workers" in its treatment of the helpers. Specifically, they charged that:

Harvard makes the helpers do exactly the same work as the better-paid journeymen;

qualified black workers have been hired as helpers instead of journeymen, even though they had several years' experience as painters. Seven of the 12 helpers are black, and three of 27 journeymen are black.

The University representatives-including John B. Butler, director of personnel; L. Gard Wiggins. administrative vice president; Dean May and Edward W. Powers. Harvard's labor-relations manager-replied several times that helpers do not have the same qualifications as journeymen.

"There are a large variety of tasks andskills in painting, and the idea is to expose the helper to all the tasks and let him become proficient," one of the officials explained.

"Helpers are training other helpers; often they are working alone," Jared Israel '67 yelled back from the crowd. Throughout the ninety-minute meeting other students said that helpers spend nearly all their time doing the same routine painting jobs as journeymen.

"Why does a black man with five years' experience as a painter need more training as a helper?" one student asked. "How do you decide who is 'qualified'?"

"We depend on our foremen to check qualifications," William Murphy, director of Buildings and Grounds, answered. He said that twice in the last year Harvard has hired black workers directly as journeymen without making them spend time as helpers.

But after a series of questions about specific cases, where-the students claimed-workers with long experience were made helpers, the administrators said they were not familiar with details of each case. "Where's the foreman?" students asked. "Why isn't he here?"

Butler and Powers said that Harvard is now reviewing the whole system of job classification with the union that represents the painters.

In answering several questions. Powers emphasized union rules. He said that any worker who felt he had been misclassify could go through a regular grievance procedure.