HP 4 FAMILY - Manual (Page 171)

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