[CentOS] Brother HL-L2360DW printing quality

I have the above printer but have not been able to resolve issues with the printing quality in CentOS 7. The test page prints fine but when I print PDF-documents, most recently using Chinese fonts, it is lacking and the pages very hard to read. The settings in the Mate Cups configuration panel are fine and set to 600 dpi, the settings in the printer menu are all OK yet it prints more like maybe 150 or even 75 dpi.

Any suggestion what might be wrong?