Avoid Non-Raster Commands — During the transmission of sequential raster bands non-raster commands should be avoided. This includes cursor positioning commands.

Separation of Images — If more than one image or picture is to be printed on a page, it is best to keep them separate. Separation consists of assuring that the new image starts with a new start raster command and that the one image does not exactly follow the next image (separate the image by at least one line vertically and sixteen pixels horizontally). This constraint improves the operation of Image Adapt.

Rectangular Images — All HP LaserJet 4 family printers perform best if raster images are sent as rectangular images to the printer. This entails keeping the right margin of the image constant and keeping all lines the full image width (no lines are truncated). Also, avoid skipping lines. When whole blank lines appear in the image, either send zeroed data row(s) or use the Raster Y-Offset command.

Avoid Unnecessary Print Model Use — Print model modes, other than source and pattern transparent, degrade memory efficiency. (This restriction is not true for the HP Color LaserJet printer.) For best results do not use an opaque source unless there is an image known to already be on the page in the same area. Following the other rules listed in this section minimizes the impact of using non-transparent print model modes.

Avoid Tall, Narrow Images — For ADC, images which are taller than they are wide by more than eight to one disable the printer’s ability to automatically separate images upon the page (this restriction is not true for the HP Color LaserJet printer). This violation is desirable in the case where the above rules are violated and multiple images are rendered as one image and sent to the printer as one combined image. Sending raster data as a checkerboard with non-full width bands sent left to right and top to bottom also disables the printer’s automatic

Memory Usage 5-5