Canon PRO-1 using vast quantities of ink
1) Do not change your ink tank when printer first advises you to. Printer advised me to change the Matte Black inktank, I did not have a replacement so I sent it to print anyhow. (Printer will stop when It runs out, and I didn't want to waste a sheet of paper). I printed eighteen 13x19's and twenty-three 5x7's on Photopaper Plus Semi-gloss before I had to change it.
2) Leave your printer turned on, I was turning mine off between prints. I got very few prints with my first ink set doing this, far less than I mentioned above. (aproximately 25-35 prints,almost entirely 5x7's, mostly one at a time). So I estimate that a power cycle can consume 2-3% of a full inktank.