The advertising agency that produced Reston Land Co.'s controversial ad that emphasized traffic problems in the Tysons Corner area says that it altered the photographs in the ad to exaggerate the traffic's appearance.

Many angry Tysons Corner area business executives and developers have been complaining that the ad featured a distorted view of traffic at Tysons.

"It seems we did use a computer," explained John Siddall, president of the Richmond-based Siddall, Matus and Coughter. His firm is responsible for Reston Land Co.'s extensive advertising campaign, currently under way, that refers to the newly opened Dulles toll road as the Reston Expressway. One of the ads in the series focused on Tysons Corner.

Siddall, asked last week if the photos had been "doctored," said they had not been altered.

Siddall now says a computer was indeed used "to add cars to the Tysons traffic jam."

Several graphics experts working in the Tysons area had also complained that the ads were doctored. Siddall's admission came in the form of a written apology.

Attorney-developer James Lewis, president of Tytran, a group of Tysons area developers and business executives formed a year ago to find solutions to traffic problems at Tysons, has been seething since he first saw the ad.

"It was bad form anyway for a company such as Mobil Oil and Reston Land who have such fine reputations to run those things attacking a fellow part of the county," Lewis said. Mobil owns Reston Land. "When they phony up the photo the way they did to falsify the situation and then lie about it, it is disturbing."

The computer took a basic aerial photo of the Tysons area looking south along Dolley Madison Boulevard and inserted images of cars back to back going north and south. In the lower right corner of the ad, a three-lane road running in one direction is shown with a sign from the Beltway pointing to a Tysons Corner exit.

The photo appears to show a jammed Beltway exit at Tysons. The actual road in that location is Westpark Drive. It is a four-lane road with traffic moving in both directions. "Westpark Drive is simply an entrance and exit road to a particular development, but if you look at that picture it looks like a Beltway exit," said one developer.

Reston Land Co. executive Michael Was said Thursday, "I knew all along what they were doing. I knew they were retouching the photos in the entire ads." A series of ads promoting the toll road as Reston's own expressway began several weeks ago.

Was said he has not heard from Tysons developers who are angry about the ads. He said the ads were not intended to attack Tysons. The focus of the campaign is to proclaim the improved access to Reston that has resulted from the opening of the new road, Was explained.

Asked about response from Reston homeowners to the campaign, Was said that "most of the comments are very positive."

That surprised one Tysons developer who said he thought the ads promoting Reston's proximity to the District ran contrary to the idea behind the concept of Reston. "I thought Reston was supposed to be the ideal place to live and work," he said.

According to Was, his company did not plan to run the Tysons Corner ad again even before the controversy over its contents erupted.