Blacks in South Africa begin to find a more sympathetic ear in the courtroom

Julia, a black woman, spent the weekend in a South African jail. When she appeared in court on Monday, she struck a contrite pose and pleaded guilty. Her crime: staying in Johannesburg, which is a designated ''white'' area , for more than 72 hours without permission.

But before the white judge passed sentence, he asked Julia if she wanted to present any evidence in mitigation. Speaking through an interpreter, Julia explained she had come to Johannesburg because it was the only place she could get proper treatment for a medical problem. Also, her husband lived in the city.

Apparently moved, the judge discharged Julia with a carefully explained and almost sympathetic warning that on future visits she should be sure not to stay in Johannesburg more than 72 hours.

Many blacks in South Africa appear to be getting a slightly fairer hearing in the courts that administer the so-called ''pass'' laws regulating black travel in the country. The laws themselves have not been changed, nor has the punishment of convicted black offenders been softened. And blacks remain principally concerned with getting the laws that do not apply to whites scrapped.

2 But in many cases courtroom procedures are improving, leading to a more respectable application of these laws, close observers say. In the past court hearings of blacks charged with pass law offenses lasted a matter of minutes and paid little heed to normal legal practices.

Now they are more thorough, giving more attention to the rights of blacks. Some judges give blacks a chance to explain their side of the story. And some take more care in explaining the laws to blacks.

''There has been an enormous change for the better,'' says Margo McWhirter, who monitors the black courts in Johannesburg for the Black Sash human rights organization. She adds, however, that the picture is still mixed in the country as a whole.

South Africa's pass laws are so encompassing that it is very difficult for a black to lead a normal life and not fall afoul of the laws. Last year these laws resulted in the arrest of more than 260,000 blacks - more than 10 percent of the black population.

Two common offenses are remaining in an urban area, without an exemption, for more than 72 hours, and failing to produce an identity document ''on demand.'' All South Africans are required to have identity documents. But for blacks - the only people subject to the pass laws - the identity documents are used to determine compliance with the pass laws.

3 Blacks are routinely stopped on the street by police checking their documents. Blacks can be held for 48 hours without a court hearing. Most have no access to legal representation. The typical penalty for pass-law violations is about $18, or 15 or so days in jail.

The change in the black courts stems from their transfer in September to the jurisdiction of the Department of Justice following a government-appointed commission's blistering attack on the practice of having a separate court system for blacks. Previously the black courts were administered by the Department of Cooperation and Development, which governs black affairs.

Since the transfer, Mrs. McWhirter says, the most evident improvement has been the higher qualifications of the judges and prosecutors in the Department of Justice.

She says the prosecutors are now ''much stricter'' about how police draw up the papers charging blacks with an offense. In cases alleging a breach of the 72 -hour provision, the arresting officer must state just how long the offender has been in the urban area.

In some areas, such as Johannesburg, the result is a reduction in the number of blacks being arrested in the first place, Mrs. McWhirter says.