I did reduce it in a step fashion, 20, 30 45 and 60 (just to see what a drastic reduction would give) I was a bit confused by PK, but now I understand, photoblack!!!!! I thought it was a terminology that people in the know use and was a bit reluctant to ask what it ment... I have been using the matt ink, but I will re run the tests with the photo ink later this week... Very silly of me really, I should have worked that one out..