| Suffix | Stands for | Description |
| _adu | ADU | Multiplied by the exposure time to convert the units to ADU (Michelle) |
| _bc | Bias Corrected | Residual bias variations removed (ISAAC) |
| _bgl | BackGround Limited | Whether or not each pixel is background limited, i.e. Poisson noise exceeds the read noise |
| _bp | Bad Pixel | Co-added with the bad-pixel mask |
| _bpc | Bad Pixel Cumulative | Cumulative bad-pixel mask (UIST) |
| _bpd | Bad Pixel Data | Thresholded bias or dark frame for bad-pixel mask creation (UIST) |
| _cl | CLone | Modifiable copy of IRCAM raw data |
| _db | De-Biassed | The bias is actually zero, but it sets up various CCDPACK ancillary data for later processing |
| _dcb | Differenced Chop Beams | The difference of the A- and B-beam signals of nodded data, as used by NOD_CHOP recipes |
| _dk | DarK | Dark subtracted |
| _dp | Differenced Pair | The difference of successive frames in a NOD recipe |
| _dta | Distortion Transfomation Applied | Resampled for field distortion |
| _ess | E-beam Sky Subtracted | Polarimetry target e-beam after sky subtraction |
| _ff | Flat Field | Divided by the flat field |
| _fm | Flat Masked | This has the flagged deviant pixels detected by the initial flat-field creation restored after object masking |
| _fpm | Fabry-Perot Masked | After a mask is applied to exclude regions beyond the circle transmitted by the Fabry-Perot etalon. |
| _md | Masked Deviants | Deviant pixels from the neighbourhood (usually
3 
in 15 x 15-pixel region) flagged as bad |
| _nl | Non-Linearity | The standard non-linearity correction has been applied (IRCAM only) |
| _nm | Normalised to Mode | Normalised masked frames combined to make the flat field |
| _om | Objects Masked | This has sources masked with bad values so that they do not bias the self flat field |
| _oss | O-beam Sky Subtracted | Polarimetry target o-beam after sky subtraction |
| Suffix | Stands for | Description |
| _qm | Quadrant Masked | One of the quadrants is masked with bad pixels, created in QUADRANT_JITTER |
| _pov | POisson Variance | Poisson variance added |
| _raw | Raw copy | Copy of the raw data, but in output directory and has history recording enabled |
| _rnv | Read Noise Variance | Variance created containing the readnoise |
| _ss | Sky Subtracted | Global or local sky subtraction applied |
| _th | THresholded | Non-physical values set to bad |
| _trn | TRaNsform | The transformed or resampled data immediately prior to making a mosaic |
| _xpr | X PRofile | Median of each row (ISAAC) |
| _ypr | Y PRofile | Median of each column (ISAAC) |
ORAC-DR -- imaging data reduction