DIFF Subgroup
G01J 1/4257 Full Title
Photometry, e.g. photographic exposure meter (spectrophotometry G01J3/00; specially adapted for radiation pyrometry G01J5/00 ) > using electric radiation detectors (optical or mechanical part G01J1/04; by comparison with a reference light or electric value G01J1/10)
Of 1 combined children, 0 exist in both systems.
1 codes are CPC-only extensions.
Note: 1 CPC extensions are marked as secondary classification only.