CUPERTINO, Calif. — Steven P. Jobs, Apple’s chief executive, announced a new line of Apple laptop computers on Tuesday that he said were made with a new manufacturing process.
Mr. Jobs introduced new versions of the company’s MacBook Pro and MacBook portable computers that are carved from 2.5-pound blocks of aluminum.
He said that the manufacturing process would allow Apple to build more rigid and reliable products.
“We end with this remarkably precise part that now only weighs a quarter of a pound,” said Jonathan Ive, Apple’s senior vice president for design.
Ever the showman, Mr. Jobs gave his audience of about 100 reporters, analysts and bloggers in a small auditorium on Apple’s campus a tutorial on manufacturing and industrial design. At one point, he passed more than a dozen finished palm-rest frames through the audience.
“It’s not only incredibly light but it’s very, very strong,” he said. “We’ve been working superhard to build unibody enclosures for some new notebooks.”
Using blocks of aluminum as the starting point for laptop cases resolved much of the speculation among Apple enthusiasts surrounding the term “brick.”
Many of them had thought the term described an entirely new product.
In July, the company’s chief financial officer said the company would shift its business model toward lower-profit-margin products in the future.
Because Apple did not announce products with significantly lower prices, speculation is still centered on products in new categories. “This is only part of the story,” Mr. Jobs said in an interview after the news conference.
Mr. Jobs deflected questions both on the company’s financial state, saying that it would report its fiscal fourth-quarter earnings next week, and on his health. He displayed a slide showing that his blood pressure was 110 over 70, adding that questions about his health would cause his blood pressure to rise.
Since appearing gaunt and pale at a previous Apple introduction earlier this year, Mr. Jobs’s health has been the subject of intense interest. The company and Mr. Jobs have responded by saying that he has not had a recurrence of pancreatic cancer, which he battled four years ago.
Mr. Jobs looked thin Tuesday, but otherwise healthy and energetic.
Apple’s challenge, industry analysts said, remains the company’s ability to defy gravity if consumers begin to spend less on electronics.
Apple has usually been considered uniquely positioned to weather the impending crisis because its highly designed products appeal to an affluent consumer less likely to be affected by an economic downturn. But unintentionally, the company may have another advantage. A delay in refreshing its laptop product line created pent-up demand for its computers.
Apple says its computers account for 17.6 percent of the American retail market by volume and 31.3 percent by revenue.
A strong product introduction during the current quarter seems to be likely, according to a number of analysts.
On Monday, A. M. Sacconaghi, a securities analyst with Sanford C. Bernstein & Company, upgraded Apple’s stock and predicted it would outperform the market.
“Apple’s short-term financials are likely to remain relatively healthy despite economic weakness,” he said.
On Tuesday, shares of Apple rose more than $5 before falling, to end regular trading down $6.18 at $104.08. The shares were rising slightly in after-hours trading.
Despite strong retail sales, the company’s stock had been hit hard by the broader market sell-off. Apple shares dropped to as low as $88.74 last week, from $189.96 in May.
The company displayed an entry level $1,999 MacBook Pro model that comes with a glass touchpad to support a new set of finger gestures to control the computer, a 15.4-inch LED backlighted display and a range of other new features.
Apple also plans to sell a 13-inch version based on its standard MacBook line, starting at $1,299.
The new models are expected to go on sale in Apple’s retail stores on Wednesday.
Apple said a new version of its thin MacBook Air with 50 percent more storage would start at $1,799. The company reduced the price of its white plastic MacBook portable by just $100, to $999.
Mr. Jobs trumpeted Apple’s relationship with Nvidia, a maker of graphics processors. Several models of the new Macintosh computers will feature two graphics processors from Nvidia, which is also supplying the integrating chipset for the MacBook Pro and MacBook.
A new Nvidia graphics processor offers five times the graphics power of the previous Intel graphics processors in the current MacBooks, he said.
The shift is a significant one that raised questions about Apple’s relationship with Intel, which supplies the central processing unit for the Macintosh.
Recently Nvidia has been under increasing pressure as Intel has moved to integrate graphics processing into its products.
“This throws a lifeline to Nvidia,” said Nathan Brookwood, president of Insight 64, a consulting firm.
