Wood handled synthetic bristle brush
Synthetic-bristle wash brushes are the preferred brush that alt-photo practitioners use when coating palladium, cyanotype, Van Dyke and gum prints. Their super fine non-absorbent bristles deliver the chemistry to the paper without streaks and their softness prevents paper abrasion that can occur when using rods or hake brushes.
The Richeson 9010 has been the go-to brush in this category, but it suffers from a key defect: it has a metal ferrule that will eventually plate out in palladium and a laquered handle whose finish will eventually crack and disintegrate.
These brushes are made in Japan by a traditional brush maker who uses a similar fine bristle material as the Richeson which is sewn into a natural wooden handle. No metal ferrule, no disintegrating lacquer.
We wet the brush in distilled before each use, and give it four or five sharp shakes to remove the excess water. The coating solution is poured onto the paper, and the brush is used to move the solution back and forth over the coating area until a smooth even coat is achieved.
We sell two sizes of these brushes. The 3" brush is appropriate for prints up to 12x16 inches or so and the 4" brush is useful for prints that are 20x24 inches.
These brushes are expensive, but comparably priced to the Richeson brush. As long as they are rinsed and cleaned after use, they will last for years and the handle will pick up a patina over time without dropping black flecks of lacquer finish onto your freshly coated print.