I would print out a test nozzle check page and see the quality that comes out.
Then I would try to make sure that your air filters are installed. IF they are not installed, please go ahead and do so.
If they are already installed, I would double check to make sure that no ink is trapped inside those air filters. If you see ink inside of them, you can remove them by placing the filters in a cup of hot water (not boiling ) and should allow the ink to dissipate.
If this is not your case still, then I would make sure that you prime the cartridges to ensure that no air bubbles are present inside the cartridge . Air bubbles inside the cartridge that escape from the ink tubes will create this dip in ink quality. Same goes for the air filters not being installed / or clogged.
I would double-check to see if these options fix you issues.
IF and if this still does not work , I would recommend priming the cartridges directly from the nozzle. This should run the ink through the back of the cartridges to ensure that ink is running through the cartridge If you print another nozzle-check thereafter, you will notice an improve in the ink quality .
Let me know if you have any questions.
Have a nice day.