HPLIP Help

I am using openSUSE 42.2, 64-bit.
I have an HP printer, so I’ve installed and configured HPLIP.
Today, while printing a .pdf file using Okular, I noticed that the print utility is something else. (I don’t know what the name of the print utility is.)
How do I get HPLIP to be the default print utility?

Which desktop? Perhaps you’re referring to the desktop print notification that might appear when a print job is active? Is hp-systray running?

I have the KDE desktop. The bar at the bottom of the desktop screen, on the right side, shows a blue circle with the characters “HP” inside. So 'm guessing that it is the hp-systray what I’m seeing.

Yes, your description is consistent with the hp-systray icon. So, all good?

No… even though HPLIP is installed, it does not seem to be the default print utility. Today, when I printed a .pdf file via Okular, some other print utility popped up. How do I make HPLIP the default print utility?

Okular is a KDE application so it will use the KDE print notifier, but HPLIP can still be used to manage the printer as well if desired.

The reason I started this thread is because when I printed the .pdf file via Okular it did so in color, even though I had told the KDE print notifier to print in grayscale (Print popup window -> Options button -> Options tab -> Grayscale button).
I therefore thought that the print notifier popup window was not the HPLIP one. But I seem to be misunderstanding things.
The question now is: Why does the KDE print notifier print in color when I tell it to print in grayscale?

Okay, that is indeed a different issue and I would have expected grayscale output. I just tried printing to file from Okular (with Grayscale selected), and can confirm that it resulted in a colour PDF, so it would seem that this is a bug.

As a workaround, one approach is to set up another print queue for same model but configured with a different print option (eg Print Quality set to Normal Grayscale). When you want to print with grayscale output select the alternative printer queue from the list.

Ok, thanks for your help.