RA_T8(1)						      General Commands Manual							  RA_T8(1)

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 RADI-
       ANCE 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 expo-
       nent  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)

RADIANCE
							      5/30/95								  RA_T8(1)