HEWLETT-PACKARD LASERJET PRINTERS and COMPATIBLES
SuperPrint version 1.1                       last updated:  16-Dec-90
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LaserJet III with only 1MB; LaserJet IIP with only 512KB
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Both the LaserJet III series and the IIP support a new compression mode
known as "PackBits" that can significantly reduce the amount of graphics
data transmitted to the printer.  Unfortunately, the LaserJet firmware
immediately expands the data, so the compression doesn't provide the
ability to print complex graphics pages with standard printer memory.

A full graphics page at letter-size 300 DPI requires over 900KB of free
memory in your LaserJet.  The standard LJ III has less than 900KB free
for graphics, so some pages will fail to print.  The standard LJ III
will successfully print most pages that have usual margins of
"whitespace", which SuperPrint detects and doesn't send (with Options...
Compression checked).  The worst-case image is one with a black
rectangle framing the printable area, and such an image won't print on a
1MB LJ III, and certainly not on a 512KB LJ IIP.

The obvious solution is to put more memory in your printer, but there is
a possible workaround for such images if they contain large amounts of
internal "whitespace".  An example would be a typical bar chart with a
full-frame border.  By switching the SuperDriver Printer Setup to
an older printer type (we recommend the IID if you have a III or IIP),
then the new PackBits compression mode isn't used, and SuperDriver uses
a "whitespace" compression based upon moving the LaserJet "cursor" and
sending smaller graphics "chunks" without significant areas of "white
space".  Even if you don't understand this, it sometimes can get your
page to print!  There's a catch, however, and it is that the amount of
data transferred can be 2-3 times as much as PackBits compression (bad
for network printing), and there is more SuperDriver compute-time
overhead.

The Version 1.1 LaserJet SuperDriver skips vertical "whitespace" even
for the PackBits III series and the IIP.  Version 1.0 did not.  This
means that some pages that failed to print completely with Version 1.0
will now print successfully on standard-memory LaserJets.


'Custom' resolutions above 300 DPI
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A reminder that the "Custom" resolution setting in the SuperDriver
"Options" dialog box is for LaserJet-compatible printers that print at
higher than 300 DPI, such as Genicom's 400 DPI laser printer.  If you
are using Genicom's printer in HP emulation mode, you will need to turn
Compression OFF.