The LILO/LIHI contains linearized (i.e., photometrically-corrected) pixels expressed in flux number (FN) units and situated in RI space. Only the pixels in a swath along the spectrum (low dispersion) and inside the target ring (high dispersion) have been photometrically corrected. The actual FN values have been scaled up by a factor of 32 for storage. The LILO/LIHI contains the LI as a 2-D primary array consisting of 768 × 768 pixels, with each pixel value coded as 16-bit, two's complement integers with bits stored in decreasing order of significance.
The associated 
flags are stored as a 2-D array the same size as
the LI data, in a FITS image extension using 16-bit, two's complement
integers. No scaling is used for the array of flags. For every
pixel that is photometrically corrected, this image contains a
corresponding flag describing specific error conditions (if
applicable) in the LI. Flagged pixels include those which suffer from
saturation, are close to the edge of the photometric correction region,
or require ITF curve extrapolation to compute an FN value. In addition,
all pixels that have not been photometrically corrected, or are known to
suffer from bright spots, reseaux, microphonics and/or missing minor
frames, are appropriately flagged. Checking for microphonic noise is
performed over the entire
768 × 768 image for the LWR camera
only. Each error condition is flagged by setting specific bits in the
data quality integer array. (See Chapter 3 for more information on how
the various error conditions are encoded.) Basic keywords in the main
header and the image extension header are shown in Table 12.6.