Most of the brushes in this category are individually handmade, with expert attention given to quality, uniformity, and longevity. The hairs are usually mounted with epoxy-type adhesive, which is resistant to solvents. The naturals include one family of brushes that is very versatile, strong and less expensive. The integrity of these brushes is very good. Their working strength and paint-holding properties are roughly the same as natural sable, and they respond almost identically to the canvas surface.
Heat mats the hairs and generally breaks down the structure of each bristle.
The ferrule of most brushes is made of nickel-plated metal and is usually seamless in artists' quality brushes. Seamless ferrules mean less possibility for solvents, paints, oils and cleaners to invade the tightly compacted brush base and that the hairs are more likely to remain in place than when a seamed ferrule is used. There are some brushes that have no ferrule at all, e.g., handmade brushes usually designed for a specific application. Lettering quills are used primarily by sign painters. Quills are made of camel hair or selected squirrel hair and are known for their resilience and smooth, square edges.