Glossary for Geospatial Science

print-raster object:  A raster that contains a dot-by-dot representation of a color print page that is viewable and can be manipulated in the TNT products like any other raster object.  Print rasters are either 4-bit (dithered) or 24-bit (undithered).  Each cell in a dithered print-raster object is a nibble (1/2 a byte or 4 bits), which can specify 16 data levels.  The 8 values currently used define one color composite dot on the printed page.  Printers create each color composite dot from dots of cyan, magenta, and yellow (and possibly black) or red, green, and blue (and possibly black).  Combinations of the three colors together with black and white are specified by each nibble’s 8 possible data levels.

You may want to create print rasters when you are planning additional modifications of the raster or you want to be able to view it before printing.  You specify the desired printer at the time you print a print raster (Main/Print From/Print-Raster).