This recipe reduces dark-frame observations with infrared imaging data. Multiple darks of the same exposure time are averaged. It files the single or averaged dark in the dark index file. Other reduction steps comprise bad-pixel masking, optional creation of data errors.

This recipe reduces a dark-frame observation with infrared imaging data. It files the dark in the dark index file. Reduction comprises bad-pixel masking, and optional creation of data errors.

• The bad-pixel mask applied is $ORAC_DATA_CAL/bpm.

• Each dark-subtracted frame has thresholds applied beyond which pixels are flagged as bad. The lower limit is 5 standard deviations below the mode, but constrained to the range $-$100 to 1. The upper limit is 1000 above the saturation limit for the detector in the mode used.

• Intermediate frames are deleted.

• Sub-arrays are supported.

• The dark called dark_$<$exposure_time$>$_$<$frame_number$>$. For single frames the group number is the same as the frame number. The decimal point in the time is replaced by p.

• The dark is filed in $ORAC_DATA_OUT/index.dark.

USEVAR = LOGICAL

• The processing engines are from the Starlink package Kappa.

• Uses the Starlink NDF format.

• History is recorded within the data files.

• The title of the data is propagated through the intermediate file to the dark.