zoobyshoe said:I've met. The very first drawing, for instance was 4-5 hours a day for the 4 days I worked on it. The colored pencil drawings take even longer. That "root system" one isn't even finished: you can see a couple of blank patches I still want to fill in. I have quite a few partially finished colored pencil drawings, more of those than finished ones. Every one is different, and I can't even give you an accurate average.
I did some portrait work in high school and it took me anywhere from 30-80 hours to complete a single piece. They were fairly large, though: about 3x4 ft or so. How big are the drawings that you are posting here?