1979719

Information

• Patent Grant
• 1979719

• References
• Source

• Patent Number

  1,979,719

• Date Filed

  Not available

• Date Issued

  Tuesday, November 6, 1934
  90 years ago

• CPC

  • G01J1/14 - using comparison with a surface of graded brightness

• US Classifications

  • 396 - Photography
  • 355 - Photocopying
  • 356 - Optics: measuring and testing