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.
Memory Usage