I have had an HP LaserJet 2550L for a long time now. Since I upgraded to 13.10, I cannot print in black and white anymore.
Before, the driver would give me an option in the Print dialog. Although I had to remember and change the setup each time I would print, since I rarely print color documents, it wasn't that bad.
However, no such option appears in the newer version. Downgrading is always a very annoying feature update!
So I looked around and found that I had to go to preferences, printers, right click on my LaserJet 2550L and select Properties.
In there, I can click on Job Options and on that screen I see defaults, including the print-color-mode which is set to Color.
Clicking on the dropdown, I can select monochrome and then click either Apply or Save. In case of Apply you immediately see the problem, it does NOT save the change (it reverts right back to Color.) If you hit Save and come back, same thing, it's still on Color and not monochrome as just saved.
In what file is that data getting saved?
I found this file: /etc/cups/ppd/hp_color_LaserJet_2550.ppd
But changing the DefaultColorSpace to Gray in that file has no effect. The list of valid values for that field are defined here:
http://www.cups.org/documentation.php/doc-1.7/postscript-driver.html
If I knew the file to which it is trying to save, I could try to edit that file instead...
P.S. I also tried to run the Python script as root and although it does not ask me for my password, it still doesn't keep my changes.
sudo /usr/bin/python /usr/share/system-config-printer/system-config-printer.py
I found a solution.
This is most certainly a case of upgrades did not make it...
Anyway, what I ended up doing (after 2 years, yes!) is to go to the System Preferences, clicked on Printer and finally, clicked on Add Printer (I used the little drop down to make sure to Add Printer and not something else.)
That new printer has the usual option, which is mind bugging, but does the job:
When printing I can again click on Properties and then I see an option "Print Color as Gray" and just select On. I can again just print in black and white!