Making Professional Pastels. Resource at Daniel Smith, by Paul de Marrias.
I made these.
The Daniel Smith stores are here in Washington state. I especially enjoy going into the Seattle store and picking out big, white bags of pigment - French Ultramarine is my favorite.
Here are some stores around the US that supply pigments and other materials:
Daniel Smith, founded in Seattle.
Utrecht Art Supplies, founded in NYC.
Rochester Art Supply, Rochester, NY.
Artisan, Santa Fe. Find Gamblin pigments there.
I guess I borrowed some pigments from a pastel stick in this instance, but pictured is a bag of Daniel Smith Whiting. The jar holds blue easel tailings.