Someone asked a ? about OS X 10.3.5, 600dpi, etc.

[null]

I can't find your post to attach a reply to so here's a blind reply...

In Terminal type:

/usr/bin/lpstat -p

To which CUPS will reply with the printer names currently active on your 
Mac. Make note of the name of the printer you wish to adjust.

Then type:

sudo lpadmin -p <printername> -o resolution=600dpi

and press Enter.

Terminal should ask you for the administrative password for the system 
and reset your printer to 600dpi.

Best,
JR