Firefox 81 is a transitional release. Firefox 82 will have a new print experience with a color/B&W selector for printers that Firefox detects are capable of printing in color.

But even though Preview always shows grayscale in Firefox 81, printing still comes out in color, at least for PDFs. I can't recall printing to a color printer with this version (sheltering in place...).

@jscher2000 The new printing interface will only be turned on for a small proportion of users in Firefox 82, and only for a week to gather the compatibility data we need to determine if it is ready for all the permutations of sotfware and printers in use out there. Most users will not see it in 82.

@rtrg1 As jscher2000 mentioned, a new printing interface is coming in the next few months. If you're curious what it looks like you can try out the experimental version of Firefox which is called Nightly Firefox. (Nightly Firefox can be run alongside normal Firefox. The two do not interfere with each other.) If you do test it out I'd be interested to hear if you encounter any issues, or generally what your experience is like.

@rtrg1 It occurs to me that somehow the print settings saved in Firefox may have ended up being broken. Can you open the page `about:config`, accept the prompt, type in "print_in_color" and see if any of the resulting preferences are false. If so, you can try double clicking them to toggle the value to true, then see if that fixes your printing problem.