Eastman Kodak Co. says the new 35mm color film for consumers introduced this week represents a major improvement in the quality of color photographs, but stock analysts said they want some proof.

Judging the quality of a photograph by looking at it is very subjective and that's the problem with the new "Ektar" color film, analysts said."How much sharper is sharper? Without a technical measure, I can't tell if it's 1 percent better or 10 percent better," said Brian Fernandez of Brean Murray, Foster Securities in New York.

Kodak has said only that the results from the new film have to be seen to be believed, but for some, seeing isn't always believing.

Eugene Glazer, of Dean Witter Reynolds in New York, said the photos he studied taken with the new film look very good, but how good is a difficult question to answer.

"I've seen plenty of superb pictures and, to a degree, I can compare them in my head, but without a side-by-side comparison it's very tough to say this is the best," Glazer said.

Kodak's chief competitor, Fuji Photo Film Co. of Japan, had little to say about the development.

"It is our policy not to comment on our competition," said Fuji spokeswoman Carol O'Loughlin in New York.

"Ektar" is an effort by Kodak to develop a color film that was considered the standard for "serious amateurs," who take about 20 percent of the 40 billion pictures made each year worldwide.

"We're not suggesting that everybody use this film," said Wilbur Prezzano, group vice president and general manager of photographic products. "We've got a terrific film for the mass market," he said of Kodacolor Gold, which the company introduced two years ago.

In fact, the "Ektar" film is not available in the speeds that are most popular in the general market: 100, 200 and 400. Its two speeds are 25, which is unusually slow, and 1000, which is unusually fast.

Other speeds may be added to the line, company spokesman Ronald Roberts said.

And Kodak suggests that only owners of 35mm single-lens-reflex cameras use the film. That suggestion is also printed on every box of "Ektar" film.