NAME

       ra_t8 - convert RADIANCE picture to/from Targa 8-bit image file

SYNOPSIS

       ra_t8 [ -d ][ -b ][ -c ncolors ][ -g gamma ][ -e +/-stops ][ -n sampfac ] input [ output ]
       ra_t8 -r [ -g gamma ][ -e +/-stops ] [ input [ output ] ]

DESCRIPTION

       Ra_t8  converts  between  RADIANCE  and  Targa  8-bit  color-mapped image files (type 1 in
       Targa's documentation).  In the default mode, a RADIANCE picture is converted to a  color-
       mapped  Targa  file  of the same horizontal and vertical dimensions with 8-bits per pixel.
       The -d option turns off dithering.  The -b option converts the image to black  and  white.
       Only  with this option can the input be taken from stdin.  The -c option allows fewer than
       256 colors.  The -g option specifies the exponent used in gamma  correction;  the  default
       value  is 2.2.  An exponent of 1.0 turns gamma correction off.  The -e option specifies an
       exposure compensation in f-stops (powers of two).  Only integer  stops  are  allowed,  for
       efficiency.   The  -n  option  specifies  a  sampling  factor  for  neural  network  color
       quantization.  This value should be between 1 and  80,  where  1  takes  the  longest  and
       produces  the  best  results  in small areas of the image.  If no value is given, a faster
       median cut algorithm is used.  The -r option invokes a reverse conversion, from  an  8-bit
       Targa  file  to a RADIANCE picture.  If the output file is missing, the standard output is
       used.

AUTHORS

       Greg Ward
       Anthony Dekker provided the code for neural network color quantization

BUGS

       Run-length encoded files can be read but not written with this program.

SEE ALSO

       pfilt(1), ra_bmp(1), ra_bn(1), ra_ppm(1),  ra_pr(1),  ra_pr24(1),  ra_t16(1),  ra_tiff(1),
       ximage(1)