Raster Graphics Adaptive Compression
(Method 5)
Raster Graphics Adaptive Compression (Set Compression Method
Command, mode 5) is implemented on the HP LaserJet IIIP, Color
LaserJet, all LaserJet 4, 5, and 6 family printers, and the
DeskJet 1200C and 1600C printers.
This compression method allows the host to compress data using a
combination of PCL compression modes to obtain optimum
compression (refer to the PCL 5 Printer Language Technical
Reference manual, Set Compression Method Command, for details).
An added benefit of this method for the HP LaserJet 4L and
LaserJet IIIP printers is that the data is not decompressed upon entry
to the printer provided the image is portrait, 300 dpi, transparent print
model and no patterns are being used. This allows the LaserJet 4L
and IIIP to print many pages which would otherwise require more
memory. As an added benefit these pages print faster. The other
HP LaserJet 4, 5, and 6 family printers decompress the data upon
entry to the printer and rely upon ADC or MEt to compress the data if
required.
For the HP LaserJet 4L printer it is critical that the image actually
compress (not expand) if Adaptive Compression is used since MEt
does not operate upon images meeting the requirements for delayed
decompression.
5-8 Memory Usage
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