Sakata Seisakusho was a Japanese company based in Tokyo. In 1939, it was making various optical products under the Melco brand, including X-ray cameras, oscilloscope devices, cameras for "special applications", medical cameras and high spec lenses. The company survived World War II: in 1953 it was still using the Melco brand for darkroom ventilation devices.
- Its address in 1939 was Kōjimachi-ku Iidamachi 2–13 (麴町区飯田町二ノ一三); in 1953 it was Chiyoda-ku Iidamachi 2-chōme (千代田区飯田町二丁目), certainly the same place after a reorganization of the postal system. Sources: advertisements in Nihon Shashin Kōgyō Tsūshin December 15, 1939 and October 1, 1953, reproduced in Hyaku-gō goto jūkai no kiroku, pp.72 and 111.
- Advertisement on p.8 of Nihon Shashin Kōgyō Tsūshin, December 15, 1939, reproduced in Hyaku-gō goto jūkai no kiroku, p.72.
- Nihon Shashin Kōgyō Tsūshin (日本写真興業通信). Hyaku-gō goto jūkai no kiroku (百号ごと十回の記録, Ten records, every hundred issues). Tokyo: Nihon Shashin Kōgyō Tsūshin Sha (日本写真興業通信社), 1967. No ISBN number. Advertisements on p.72, corresponding to p.8 of the December 15, 1939 issue, and on p.111, corresponding to p.13 of the October 1, 1953 issue.