TRUTH SERUM FOR DIGITAL PICS

From the material found on his hard drive, Bryan Sparks of Springfield Township, Ohio, seemed guilty when he was arrested in 2002. The sexually explicit pictures of minors appeared to put him on the wrong side of child pornography laws. But at his trial this spring, Mr. Sparks was acquitted because no one could tell for sure whether the images were authentic or just clever digital forgeries.

Mr. Sparks was eventually convicted on a separate charge of rape and sentenced to life in prison. But the uncertainties that surrounded his case, and others like it, are driving researchers to develop software that can automatically figure out which digital pictures are real and which ones are fake.

"It used to be that you had a photograph, and that was the end of it - that was truth," said Hany Farid, an associate professor of computer science at Dartmouth College who is a leader in the field. "We're trying to bring some of that back. To put some measure of guarantee back in photography."

My article in today's New York Times has details. (In one of those odd bunchings that sometime happen in freelance work, the Times is also running a second story by me today, on politically-themed dating sites.)