Berliner Gramophone formulations remained the standard disc record material until the first vinyl records – initially made only for radio use and other special applications – were introduced in the 1930s. Beginning in 1896, Berliner's gramophones were made by Philadelphia-based machinist Eldridge Johnson, who added a spring motor to drive the previously hand-rotated turntable. Berliner also opened an office in New York City, staffed by Frank Seaman and O. D. LaDow and organized as the National Gramophone Company. Master recordings were made onto zinc plates, which were then electroplated and a negative-image "mother" made from them to stamp discs. A major reversal
Unusual types of gramophone records all 7-inch until 1901, when 10-inch records were introduced. 12-inch records joined them in 1903. By 1910, other sizes were retired and nearly all discs were either 10-inch or 12-inch, although both sizes were normally a bit smaller than their official diameter. In Europe, early 10-inch and 12-inch shellac records were produced in the first three decades of the twentieth century. 7-inch children's records were sold before World War II but nearly all were made of fragile shellac, not an ideal material for use by children. In the late 1940s, small plastic records, including some small picture discs, replaced them.