DIFF Subgroup
G01J 1/1626 Full Title
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 electric radiation detectors (G01J1/20 takes precedence)
Of 6 combined children, 0 exist in both systems.
6 codes are CPC-only extensions.
Note: 6 CPC extensions are marked as secondary classification only.