Color printing from Photos has suddenly degraded--why?

Not entirely sure I got the image "outside the library"--I brought it up with Photos, then used Preview to "copy" it using the selection option, then printed it. The result was much better than what I have been getting, although, of course, it was on regular printing paper rather than photo paper. There was no "puddling" of the blacks, and color was essentially normal.

I exported to the desktop, but, then when I printed, rather than just the usual, simple printing from Preview, the options to set printing up for the printer came up and I set them as close as could to how I print color prints. Got the image on the 4x6 print paper, and it was again downgraded as before--much worse than when I printed using Preview before without setting any printing parameters. I then couldn't seem to get back the option to print in the usual Preview way, even though was still in Preview. However, that first time, even though I may have been using the image from the library, printing from Preview gave MUCH better image.

I did another cold boot of computer, turned off printer, brought up the exported image and printed using Preview, but this time reset printing parameters to "default" and printed on letter sized regular paper. Once again, the outcome was what I interpret as "normal" from printing with the resolution expected with Preview for an enlarged image on regular printing paper. I then went again into Photos and printed on 4x6 photo paper using the usual settings except substituting "default" for "fine" in one of the settings and again got the poor quality with xs black dots and general excess of print. It is as if the printer is trying to both print in color and in fine B&W at the same time. In past, including last night, it has been necessary to set one of the settings to "fine" in addition to indicating photo paper. To me, it seems as if something in the message to the printer, whether from Photos or from the printer control program, is misfiring.

Reset did not help. Have not been able to find driver for MX 920 series or my specific 922 printer listed, although there was long list of MX drivers, including 924. Have contacted Canon on line for assistance, but have not heard from them.