Color laser printers and the IIgs...some Musings

["Christopher G. Mason" <cgm1@my-deja.com>]

Recently I purchased a HP Color Laserjet 3700dn printer, keeping in mind 
that it would only print in black and white on my Apple IIgs using the 
built in Laserwriter driver. Then I started to think, how hard would it 
to be to get it to print in color? Did anyone ever write a 3rd party 
Postscript driver for GS/OS? It seems that it would be fairly trivial to 
add support for color to the driver and a few other modern features 
(like duplexing and support for more then 2 trays) due to the simplicity 
and independent nature of the Postscript language. Heck, lets even throw 
in RAW Port 9100 TCP/IP printing via Marinetti while we are dreaming 
(actually this could likely be written as a virtual "port" driver and 
support all existing printer drivers like Harmonie). Of course that all 
depends on how hard and complicated it is to (re)-write a GS/OS printer 
driver. Source code to the existing driver would be nice, but we'll 
likely never see something like that from Apple.

As for 8-bit programs, the problem is pretty much solved. I managed to 
add color support to the IWEM Postscript emulator Apple provided with 
GS/OS. It has the same limitation as the Virtual ][ emulator's IWII 
support in that it doesn't support overprinting colors. This is a 
limitation of the Postscript imaging model as it doesn't support 
blending colors. As long as a program sticks to using the Imagewriter 
II's escape codes directly for the 3 blended colors (as in letting the 
printer blend orange, purple, and green on its own) they will print. 
Sadly The New Print Shop is one of those pesky programs that blends 
colors on its own by manually doing two passes or each primary color.

Also, if anyone has trouble using IWEM on modern Postscript printers, 
you must turn off automatic language switching or "personalities" and 
force the printer into Postscript-only mode. Otherwise the printer will 
likely spew pages of garbage instead of the emulator handling the 
Imagewriter data. Other problems I have encountered is the confirmation 
page that states the emulator has been installed won't print and you 
sometimes have to manually send a Control-D to the printer to get it to 
eject a printed page.