G01J 1/14 using comparison with a surface of graded brightness,
Introduced: September 1968
Title
Titles differ between systems:
IPC: using comparison with a surface of graded brightness
CPC: using comparison with a surface of graded brightness,
Full Title
Full titles differ between systems:
Photometry, e.g. photographic exposure meter > by comparison with reference light or electric value > using wholly visual means > using comparison with a surface of graded brightness
Photometry, e.g. photographic exposure meter (spectrophotometry G01J3/00; specially adapted for radiation pyrometry G01J5/00 ) > by comparison with reference light or electric value > using wholly visual means (G01J1/20 takes precedence) > using comparison with a surface of graded brightness,
No child classifications to compare. This is a leaf node in both IPC and CPC.