The NIRSpec MSA imprint subtraction step removes patterns created in NIRSpec MOS and IFU exposures by the MSA structure. This is accomplished by subtracting a dedicated exposure taken with all MSA shutters closed and the IFU entrance aperture blocked.

The step has two input parameters: the target exposure and the imprint exposure. These arguments can be provided as either a file name or a JWST data model.

The SCI data array of the imprint exposure is subtracted from the SCI array of the target exposure. The DQ arrays of the two exposures are combined using a bitwise logical OR operation. The ERR and variance arrays are not currently used or modified.

Step Arguments

The imprint subtraction step has no step-specific arguments.

Reference File

The imprint subtraction step does not use any reference files.