Readme file for the hpxx drivers V 1.3


CREDITS: Much of the driver is based on ideas derived from the cdj550 driver of George Cameron.

The support for the hp670, hp690, hp890 and hp1600 was added by Martin Gerbershagen.


Copyright (C) 1996-1998

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.


   11.11.96. Initial release of the driver 

   25.08.97  Version 1.2. Resolved all but one of the 
                          known bugs, introduced a couple
			  of perfomance improvements. Complete
			  new color-transfer-function handling.
			  (see gamma).

  01.06.98   Version 1.3  Due to the most welcome contribution
                          of Martin Gerbershagen (ger@ulm.temic.de),
                          support for the hp670, hp690 and hp890
			  and hp1600 has been added. Martin has also
			  resolved all known bugs.

	     Problems  :  Dark colors are still pale.
	                  
The diver needs no longer special switches to be invoked except -sDEVICE=cdj850, or -sDEVICE=CDJ890, or sDEVICE=CDJ670 or -sDevice=CDJ1600

The hp690 is supported through the hp670 device, the hp855, hp870 and the hp1100 through the hp850 device.

The driver implements the following switches:

   -dPapertype= 0  plain paper [default]
                1  bond paper
		2  special paper
		3  glossy film
		4  transparency film

		Note, currently the lookuptables are not suited
		for printing on special paper or transperencies.
		Please revert to the gamma functions in this case.

   -dQuality=  -1 draft     
                0 normal       [default]
                1 presentation 

   -dRetStatus= 0 C-RET off
                1 C-RET on [default]

   -dMasterGamma= 3.0 [default = 1.0]
    __Note__: To take advantage of the calibrated color-transfer
              functions, be sure not to have any Gamma-Statements
	      left! If you need to (i.e. overhead sheets), 
	      you still can use the gamma-functions, but they will 
	      override the built-in calibration. To use gamma in the 
	      traditional way, set MasterGamma to any value greater
	      1.0 and less 10.0. To adjust individual gamma-values,
	      you have to additionally set MasterGamma to a value
	      greater 1.0 and less 10.0
	      
When using the driver, be aware that printing in 600dpi involves processing of large amounts of data (> 188MB !). Therefore, the driver is not what you would expect to be a fast driver ;-) This is no problem when printing a full sized color page (because printing itself is slow), but it's really annoying if yoy print only text pages. Maybe I can optimize the code for text-only pages in a later release. Right now, it is recommended to use the highest possible optimisation level your compiler offers.... For the time beeing, use the cdj550 device with -sBitsPerPixel=3 for fast proof-prints. If you simply want to print 600dpi b/w data, use the cdj550 device with -sBitsPerPixel=8 (or 1).

Since the printer itself is slow, it may help to set the process-priority of the gs-process to regular or even less. On a 486/100MHZ this is still sufficient to maintain a continuos data-flow. Note to OS/2 users: Simply put the gs-window into the background, or minimize it. Also make sure, that print01.sys is invoked without the /irq switch (great speed improvement under warp4).

The printer default settings compensate for dot-gain by a calibrated color-transfer function. If this appears to be to light for your business-graphs, or for overhead-sheets, feel free to set -dMasterGamma=1.7.

Furthermore, you may tweak the gammavalues independently by setting -dGammaValC, -dGammaValM, -dGammaValY or -dGammaValK (if not set, the values default to MasterGamma). This will only work, when -dMasterGamma is set to a value greater than 1.0.

If you want to learn more about gamma, see: http://www.erdw.ethz.ch/~bonk/ftp/misc/gammafaq.pdf

http://www.erdw.ethz.ch/~bonk/ftp/misc/colorfaq.pdf

Note: Depending on how you transfered the files, you might need to remove some CR-codes used on intel-based machines: simply type: unzip -a hp850.zip to compile with gs5.x, add DEVICE_DEVS4=cdj850.dev cdj670.dev cdj890.dev cdj1600.dev to your makefile.

BTW, it is always a good idea to read make.txt found in the gs-distrib before attempting to recompile.....

Feel free to mail feedback or problems to bonk

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