The basic brush is divided into three parts: the handle, the ferrule and the bristles. Brush handles are primarily made from wood or acrylic plastic. The ferrule, whose primary purpose is to attach the bristles to the handle, is normally made of brass or nickel or stainless steel. The head of the paintbrush is a collected bundle of hairs referred to as the brush bristles. The brush bristles can be viewed as three sections. The end of the brush bristles closest to the ferrule is called its heel. The opposite end of the brush bristles is called its toe or tip. The center section of the brush bristles is called its belly or reservoir. The brush head hair mixture can be composed of different types of natural animal hair or synthetic, man made, hair or a blend or mixture of natural and synthetic hairs.

For watercolor brushes, important characteristics of the brush head are its sponge like properties associated with moisture retention and release; and its stroke producing properties associated with the spring back or snap of the hairs and their ability to maintain a point. The hair type or types that comprise the brush head produce these characteristics of the brush.

The bristles of a brush act as a sponge. It’s sponge characteristics depend on the size and type of brush and the hairs used for the brush head. Natural hairs through their inherent shapes exhibit different absorption and retention characteristics as well as different moisture release properties. The natural hair types that start out with a thin shaft that thickens in the middle and ends in a sharp point make ideal watercolor brush hairs. (see picture below) They come to a nice point when bundled while forming a thick belly or reservoir in the middle. Squirrel, sable and weasel hair all point well and form substantial reservoirs. Sable and weasel hair have the added property of having excellent natural spring back or snap characteristics. Squirrel loses its shape during usage as it dries out. Many synthetic hair types have a constant diameter shaft size that ends in a sharp point. These types of synthetic brush heads have excellent pointing and snap characteristics but they produce smaller belly reservoirs and also have a tendency to release their moisture load or charge more unexpectedly in what is commonly referred to as a quick dump. Natural hair brushes typically release their moisture load more evenly during a stroke.

Synthetic hairs can be extruded to mimic the shapes of natural hairs which can greatly improve their brush characteristics. Additionally, combinations of different natural hairs such as weasel and squirrel in combination with improved synthetic shapes can produce hybrid brush heads that perform equal to or better than some natural hair brushes at a fraction of the cost of the all natural hair brushes.

In watercolor painting, the brush is used to mix paint, pigment with water. The brush is then used to pick up the moist color and deliver it to the paper. Characteristics of a brush which are important begin with how the brush picks up and carries the color mixture. When a brush picks up color we refer to that as its load or charge. How much of a charge a brush can handle is its charge capacity. And how much of a charge it controllably can deliver from palette to paper is its carrying capacity. Once a brush delivers the color mixture to the paper it is used to produce strokes or marks. In producing its potential strokes the brush releases its charge in a characteristic fashion often referred to as its release characteristic. Ideally the more controlled and predictable the charge is released the better. A consistent even charge release is very controlled and predictable while an uneven front ended dump release is difficult to control or predict. The release during a stroke is to a degree controlled by the pressure applied to the brush against the paper but it also is a function of the release characteristics of the brush in use. Therefore each brush by its design and construction has charge carrying and charge release characteristics that make it more or less suitable for usage by the artist. In general control and predictability as well as delivery capacity are very important to the artist. Control and predictability and their importance is fairly obvious. Delivery capacity in terms of how often a brush must be reloaded is critically important in a time sensitive process like working with watercolors which is constantly moving from wet to dry. It effects washes, edges, blooms and blossoms and other aspects of the work.

In part 2, I will explore the different brush types (flats, rounds, mops, liners and riggers etc.) different brush sizes , and characteristic pros and cons and applications for different brush types.