Thanks everyone for your comments and emails, I am glad people are enjoying my process shots and notations about my materials.
I created this painting using round brushes, I started sketching with size #8 and spent the second half of the day with size #2. I also used a #14 filbert to smooth out the background.
I always paint with two brushes at a time of the same size and shape - well, I paint with one brush and hold the other in my left hand, with the palette. I switch back and forth between the brushes constantly, occasionally giving them both a good cleaning in my Silicoil jar of turps. One brush is reserved for lights, and one for darks, which helps me keep my brushes and colors clean.
I tend to settle on 3 so-called "primaries" plus Titanium white, even if I start out with more colors laid out on my palette. Today I used: Cadmium Yellow Deep, Permanent Violet Medium, and Ultramarine Blue (all Rembrandt brand). I also used Sennelier brand Phthalo Green Cool, which helped capture the bright green light shining through the vase - better than Ultramarine & Cad yellow mixed together would have.