Traditionally artist brushes only used natural hairs for the filament, but modern synthetic fibers offer a great alternative and are typically more economical. Filaments vary in stiffness, resilience, strength and each reacts differently to various types of paints and liquids. Softer filament options are great for details and a thinner paint, while thick, robust filament is ideal to push around heavy paints.
Tanis offers the following fill material options:

- Bristle is hog hair that carries liquids well while maintaining its shape and stiffness in use over a long period of time. Bristle naturally splits at the end which carries more liquid medium.
- Ox hair is a fiber from the ears of cattle or oxen and is very silky to the touch. It is a strong, springy, resilient hair that is more rigid than sable and as stiff as natural bristle.
- Red sable is reddish-brown in color and made from hair from weasel tail. It is soft to the touch, naturally forms a point and is less resilient to solvents and the chemicals found in oils.
- Black sable is a natural hair typically from weasel tail. This high-quality hair carries a lot of fluid and is springy and soft and naturally forms a point, giving you a lot of control.
- Pony hair is a fiber from the belly of a horse and it is strong, resilient, slightly coarse and very absorbent.
- Camel hair is not actually from a camel, but is made from various inexpensive hairs mixed together like pony, bear, sheep and squirrel. This soft hair is used in the less expensive brushes.
- Taklon is a synthetic alternative to the natural fibers and is versatile and extremely durable.
- Gold nylon is a synthetic alternative and has excellent absorption qualities and the flexible, malleable fibers allow for easy contouring.



