blank correction 

https://doi.org/10.1351/goldbook.08008
Step in a measurement procedure in which the effect of a blank indication is removed from an indication.
Notes:
  1. The blank indication and the indication must be of the same kind of quantity.
  2. A blank indication may be subtracted from an indication, or, in the case of a transmittance measurement, the indication is divided by the blank indication.
Source:
PAC, 2021, 93, 997. 'Metrological and quality concepts in analytical chemistry (IUPAC Recommendations 2021)' on page 1001 (https://doi.org/10.1515/pac-2019-0819)