When I returned to a sketch I was in the middle of, I realized that my pencil line was no longer deft and black. No matter the pressure, I get a mottled blue to black line. I thought maybe my black was not set on black, or opacity wasn't 100% or my layer settings were not right. Admittedly, I don't understand some of the layer settings, but nothing I try changes it. Here's a link to an example. https://dl.dropboxusercontent.com/u/6401104/SAMPLE.jpg

Help! I can't stand this.