The Catalyst Polytip series is my go-to line of brushes. I work in oil colors, and I like using synthetic brushes more than natural-hair brushes. This Polytip series gives the best of both due to the flagged tips which mimic natural bristle. These brushes aren’t your usual synthetic — they handle both thick and viscous oil paint easily. I have been using these brushes since they first came out. I use them in the studio, and I also use them while doing plein air work, especially if I’m using water-soluble oils, as these brushes keep their integrity, snap, and clean edges even while wet with water, unlike hog-bristle brushes. In the studio I mainly use the filbert shapes, in the beginning stages of working, to rough in large masses and establish the feeling and mood of the painting. My favorite brush in the series is the size 6 Egbert. Because of the extra-long hairs and responsive feel of this brush, I can use it to draw shapes and fill in mass at the same time. I also like to use it to finish a painting, to add those calligraphic marks and highlights.