When BS 935:1941 was published during World War II, specifying exposure tables for negative materials, it employed the same fixed-density speed criterion used in the German DIN 4512:1934 system. The British Standard also used logarithmic speed numbers, following the example of Scheiner and DIN. When the American ASA Z38.2.1:1943 standard was published, it used a fractional gradient speed criterion and arithmetic speed numbers, for compatibility with Weston and GE.