HP LaserJet 4P won't print grayscale

[Tristan Miller]

Greetings.

Our HP LaserJet 4P works great for black-and-white text and line art, but
won't print anything in grayscale -- if we send it a document or image
from any application which contains colour or gray areas, those areas are
printed so lightly as to be invisible. This holds regardless of the REt
Setting, Toner Density, Printout Mode, and Resolution/Quality settings.
I'm also sure it's not a software fault as we've tried hooking the printer
up to various Windows and GNU/Linux boxes and printing from several
different applications. However, if we first manually convert a document
with colour or grayscale to a dithered 1-bit black-and-white image, then
it prints just fine, even at 600 dpi.

What would be causing this behaviour, and how can we fix it? If it's not
possible to fix it, is there some sort of software filter we could install
in the printer firmware, printer server, or even printer clients which
will convert all incoming documents to black and white before sending them
to the printer? Currently the printer is hooked up to a CUPS print server
on a GNU/Linux machine; the other machines on the network are running
either GNU/Linux or MS-Windows XP.

Regards,
Tristan

 

[The Natural Philosopher]

Greetings.

Our HP LaserJet 4P works great for black-and-white text and line art, but
won't print anything in grayscale -- if we send it a document or image
from any application which contains colour or gray areas, those areas are
printed so lightly as to be invisible. This holds regardless of the REt
Setting, Toner Density, Printout Mode, and Resolution/Quality settings.
I'm also sure it's not a software fault as we've tried hooking the printer
up to various Windows and GNU/Linux boxes and printing from several
different applications. However, if we first manually convert a document
with colour or grayscale to a dithered 1-bit black-and-white image, then
it prints just fine, even at 600 dpi.

What would be causing this behaviour, and how can we fix it? If it's not
possible to fix it, is there some sort of software filter we could install
in the printer firmware, printer server, or even printer clients which
will convert all incoming documents to black and white before sending them
to the printer? Currently the printer is hooked up to a CUPS print server
on a GNU/Linux machine; the other machines on the network are running
either GNU/Linux or MS-Windows XP.

Regards,
Tristan

..bbbut laserjets are BLACK AND WHITE printers...they don;t have grey
ink/toner you know..this mapping of grayscale to dithering ALWAYS has to
be done SOMEWHERE..


You need a shim driver between whatever your applications are producing
and the printer..normally this is an HP driver on a PC, on Linux no
idea..ghostcript mebbe? I know very little about that area.

 

[Tristan Miller]

Greetings.

.bbbut laserjets are BLACK AND WHITE printers...they don;t have grey
ink/toner you know..this mapping of grayscale to dithering ALWAYS has to
be done SOMEWHERE..

Yes, of course. The point is that the printer itself normally takes care
of this, but in this case it's failing to.

Regards,
Tristan

 

[Jacques E. Bouchard]

Greetings.



Yes, of course. The point is that the printer itself normally takes care
of this, but in this case it's failing to.

Did you try adjusting contrast and dithering in the printer's setup
dialogue? Also, there should be a switch inside the printer that lets
you adjust intensity (my HP 4si had one).



jaybee