Hillman Curtis, a former rock musician who became a prominent first-generation Web designer and a visionary figure in the Internet’s evolution from a predominantly text-based medium to the multimedia platform it is today, died on Wednesday at his home in Brooklyn. He was 51.

The cause was colon cancer, his wife, Christina, said.

Mr. Curtis was the art director of a San Francisco software company in 1996 when he designed the first Web site formatted for a new technology called Flash Player, a browser plug-in that could be used to turn out high-quality animated imagery quickly. Before then the process would take hundreds of hours.

His mastery of the technology, which had been developed for several years before but never fully deployed in a way that unveiled its creative potential, made Mr. Curtis a revered figure in the emerging world of Web design.

His Flash Player design technique set the groundwork for a format that later evolved exponentially to accommodate online advertisements, Facebook applications and video sites like YouTube.