Preliminaries

There are a few operations applied to all frames. First the raw frame may be displayed.
[general/_DISPLAY_FRAME_IMAGE_]

Recipes remove any AXIS and blank TITLE components; the latter to preserve the object name when NDFs are exported to FITS. Next they set the origin of the frame so that frame pixels retain the detector pixel indices. It then becomes possible to use a full-sized bad-pixel mask or flat field on any subset of a detector's pixel grid.
[_REMOVE_AXES_, _REMOVE_BLANK_TITLE_, _SET_ORIGIN_]

Then recipes determine the displacements of the reference pixel with respect to the centre of the frame and stores the displacements in the referenceoffset calibration system. The reference pixel is where a star would be placed for photometry or the centre of a chopped and nodded pattern.
[_SET_REFERENCE_PIXEL_OFFSET_, _GET_FRAME_CENTRE_]

The next step is to switch on history recording. It is recommended to leave this enabled, since it provides a record of the processing steps of your final mosaics. Otherwise the pipeline becomes something of a black box. Use the KAPPA command hislist to list the history records.
[_TURN_ON_HISTORY_]

For Michelle there is a validation check of the waveform used, comparing the waveform name given in the headers with other metadata, and recipes issue a warning if there is an inconsistency. Also the data range is validated to be between 25000-48000.
[MICHELLE/_CHECK_WAVEFORM_, MICHELLE/_VALIDATE_RAW_DATA_]

For UFTI there is data validation, such that a warning is issued if the clipped mean sky level is below 24 counts per second in $K$ band and 32 counts per second in $H$.
[UFTI/_CHECK_SKY_COUNTS_, UFTI/_VALIDATE_RAW_DATA_]

For UIST data taken before 2002 December 2 and Michelle, raw data units are converted from ADU per second to the UKIRT standard of total ADU per exposure.
[$<$instrument$>$/_INSTRUMENT_HELLO_, UIST/_DATA_UNITS_TO_ADU_]

A night log is created or appended in $ORAC_DATA_OUT for each frame processed. This tabulates the main parameters of the observation having first corrected defective or undefined headers.
[_NIGHT_LOG_, UIST/_NIGHT_LOG_, $<$instrument$>$/_FIX_HEADERS_ for Classic Cam, IRCAM, MICHELLE, NIRI, and UFTI]