The wMaxGray box contains the maximum value that the Universal Printer
Driver can pass as an argument in the printer's gray-fill command.
Diconix 150 Plus
The wMaxGray box is empty.
HP LaserJet IIP
For the HP LaserJet IIP printer, the maximum percentage of black pels is
100. (This means that there are 100 black pels and 0 white pels in the
maximum shade or fill pattern.)