Mammoth plate, an outsize format used by some 19th-century view specialists, notably photographers of the American West like Carleton E. Watkins. On his 1867 journey up the Columbia River in Oregon, for example, Watkins employed 41.3 × 52.7 cm (16 1/4 × 20 3/4 in) plates to create magnificent images such as Cape Horn near Celilo. On other occasions he used even larger, 45.7 × 55.9 cm (18 × 22 in), plates. Other users of the mammoth format included Mathew Brady, William Henry Jackson, and Eadweard Muybridge.
— Robin Lenman
