I made about 100 images (total since I installed the inks for the first time) and had everything calibrated for matte black with German etching using the Piezo pro K-4 inks. I then switched over to photo black to make a digital negative with the PiezoDN-ProK4. I then switched back to the matte prints. The printer did a normal cleaning and I did a power cleaning and when I made a print of the same image with the same profile, it came out warmer and darker. I only thing I can think of is to re-calibrate since maybe I still had some old ink from when I first installed the inks.
The other question I am wondering is, the printer is a 9900 with one dead nozzle, since I have it as the Pro K4, does it make sense to move the photo black to an extra nozzle and remap it since I have one free? This way I am not wasting so much ink when I switch between the two?