Print quality issues in GSport 0.31 Windows with both Virtual ImageWriter and Epson LQ

[Jadan Bliss]

Greetings,

I would like to thank the developers who started and those who maintain and contribute to this project. I am attempting to print from the original Print Shop, using GSport as an Apple II. In Print Shop, I have selected Epson MX-80 as well as Old Epson with Graftrax-80.

I have tried everything I could find on the subject of printing with GSport, starting but not ending with gsport.sourceforge.net/printer.html.

When I print to an Epson printer, the result is not using the full width of the page as it would on a real printer, and the image runs off of the page into the next. From what I understand, the Epson 9-pin dot matrix printers printed at 120dpi x 72dpi.

When I print to an ImageWriter, the printout seems properly proportioned, but there is misalignment resulting in missing vertical lines, and sometimes parts of the image shift by a pixel.

I have tried using "Printer Port" as well as "Your Card" in slot 1. I have tried printing to Epson as a parallel and ImageWriter as serial. I have tried as BMP output, and PostScript. What would be causing this issue?


Thank you,
Jadan Bliss

[Christopher G. Mason]

Post by Jadan Bliss
When I print to an Epson printer, the result is not using the full width of the page as it would on a real printer, and the image runs off of the page into the next. From what I understand, the Epson 9-pin dot matrix printers printed at 120dpi x 72dpi.

The Epson LQ emulation isn't very friendly to software expecting a 9-pin
printer. The problem is the 24-pin Epson LQ line prints at 1/60in dot
spacing in low resolution vs 1/72in the 9-pin printers outputted.
Printing to a real Epson LQ with a MX-80 driver will show the same
squashed print out.

Post by Jadan Bliss
When I print to an ImageWriter, the printout seems properly proportioned, but there is misalignment resulting in missing vertical lines, and sometimes parts of the image shift by a pixel.

The ImageWriter LQ emulation should have no problems with the classic
Print Shop as I use it to test. The vertical lines are scaling artifacts
and can be avoided by switching the output resolution to 1440x1440dpi.
The current trunk of GSPort has improved ImageWriter emulation, for one
the left margin is properly set at 1/4in by default.

FWIW, the Epson emulation has bugs that likely won't be fixed. Stick
with the ImageWriter emulation for now on. Its likely the Epson LQ
option will be phased out in later revisions of GSPort. It was
originally a stop gap solution for printer emulation until ImageWriter
support was added.

[Jadan Bliss]

Ah, that's what I was doing wrong. It prints perfectly at 1440x1440 dpi. Thank you!

Post by Christopher G. Mason
The ImageWriter LQ emulation should have no problems with the classic
Print Shop as I use it to test. The vertical lines are scaling artifacts
and can be avoided by switching the output resolution to 1440x1440dpi.
The current trunk of GSPort has improved ImageWriter emulation, for one
the left margin is properly set at 1/4in by default.
FWIW, the Epson emulation has bugs that likely won't be fixed. Stick
with the ImageWriter emulation for now on. Its likely the Epson LQ
option will be phased out in later revisions of GSPort. It was
originally a stop gap solution for printer emulation until ImageWriter
support was added.

[Jadan Bliss]

What interface do you use in Print Shop? Apple Super Serial still gives a few artifacts, and Apple III Serial Interface crashes Print Shop altogether.

How do I get the current branch of GSport? I can wait if it's near release.

Post by Christopher G. Mason
The ImageWriter LQ emulation should have no problems with the classic
Print Shop as I use it to test. The vertical lines are scaling artifacts
and can be avoided by switching the output resolution to 1440x1440dpi.
The current trunk of GSPort has improved ImageWriter emulation, for one
the left margin is properly set at 1/4in by default.

[Jadan Bliss]

Thank you for your help.

[Jadan Bliss]

I think the artifacts I'm seeing are just Print Shop quirks. (It doesn't scale the graphic perfectly when printing it large on a sign). I was also seeing a few dots at the top of pages, but that was apparently due to masking off the high bit on the serial port. It works well enough now.

Thank you again.