New user printing problem with HP1600

Being new with Macs I am seeking help with my HP1600 color laserjet printer. I downloaded the recommended software and had the printer working perfectly but for some reason it is now only printing black and white. Color levels are good and it prints color on other computers. I can't find anything in the settings.
Would appreciate any help to get back to the world of color. Many thanks.

It's likely that either the colour heads are clogged, or (more likely) a setting in your print dialog or page setup dialogue is telling the printer you WANT to print in black and white. I'd start by double-checking those.

If there's no obvious "aHA!" moment, I think most HP printers can do their own self-test printed page, so I'd try that next just to make sure that (independent of the computer) the printer can print in colour properly.