My Materials

I use a water bin, an old listerine bottle to carry water in, masking tape, Winsor and Newton watercolors, white gouache, brushes; mostly Princeton (Princeton 1” flat #4350st) and Robert Simmons white sable (#721 flat, sizes 1/2” and 1/4”), sketchbooks and a small hiking pack they all fit in. The sketchbooks are heavy weight, acid free craft paper made by Canson (can be found as a scrapbook in the photo album section of art and stationary stores). I use the Alvin Heritage Artists Palette. 

You can see numerous demonstrations and a full exploration of my approach in my online course.

The studies are done small and quickly. Most are less than 3x5" and completed in 20 minutes to an hour.
 
My watercolor palette. (all Winsor and Newton brand unless otherwise noted.)
permanent white designers gouache
winsor lemon
winsor yellow deep
yellow ochre
winsor orange
winsor red
permanent alizarin crimson
french ultramarine blue
phthalo blue (winsor blue greenshade)
phthalo green (winsor green blueshade)
permanent sap green
leaf green (Holbein brand)
venetian red (or indian red)
raw umber
van dyke brown
ivory black