Steinweiss's first cover was for a collection of Rodgers and Hart show tunes. Although it was patented in his name, its rights were retained by Columbia. The heavy paper used for 78s damaged the narrower and more delicate grooves on the LP record, so Steinweiss designed the folded-over board format sleeve which quickly became the standard packaging for LPs.
The advent of the long-playing 33⅓ record brought Steinweiss's vision to the fore.
A Bruno Walter recording of Beethoven's Eroica showed a huge increase in sales with its new sleeve, and Steinweiss became Columbia's art director. His first cover featured the title of a collection of Rodgers and Hart show tunes up in lights on a theatre marquee. In 1939, while designing ads for Columbia Records, Steinweiss suggested adding art to the company's 78 releases, which were then generally sold in heavy paper and, for multiple-record sets, packaged in plain, book-like binding. Alex Steinweiss, who has died aged 94, pioneered the concept of record album covers, when music was still released on 78rpm shellac, and was the inventor of the LP record sleeve.