Paintbrushes have a lot of competition these days from rollers, painting pads and other applicators, but a brush is still needed in most cases for finishing in corners and along edges, as well as in narrow places a roller can't reach.

A good quality paintbrush is also essential for such jobs as "cutting in" windows, molding and trim, as well as for painting and finishing of furniture, cabinets, paneled doors and similar surfaces where a smooth professional looking appearance is wanted.

To accomplish these tasks, the paintbrush must be the right type for the job at hand, and it must be carefully cleaned after each use.

A good paintbrush is expensive, and worth taking care of-and the only kind to buy when a quality finish is desired.

Paintbrushes today have three types of bristle: natural hog bristle, nylon and polyester. Each has its advantages and disadvantages, and each is used in brushes of all sizes and shapes, so you should know something about their characteristics to be able to choose the one that will best meet your needs.

Hog bristle, a natural product, has been used in making paintbrushes for many years; the best are those from China. The bristles are naturally tapered and flagged at the tips-a combination of qualities that makes them strong and flexible and helps them to spread the paint uniformly. This type is excellent for use with oil-base paints and enamels, but it is not suitable for use with water-thinned paints.

Nylon is a synthetic filament that resists wear much better than hog bristle, but it should be used mainly for water-thinned paints. The better nylon brushes have their bristles flagged and tapered to equal the working qualities of the natural product, but nylon tends to get soft in hot weather and loses much of its springiness after a few hours. Nylon gets soft and floppy when used in shellac or lacquer, as well as when it is used with some quick-drying enamels and varnishes.

Polyester is the newest of the synthetic filaments, and in many ways it is probably the best. It does not soften when used in latex paints, and it keeps its resiliency much better than does nylon when used in hot weather. Nor does it lose its flexibility when used with lacquer, shellac and most common solvents, so it can be used with almost any type of paint or finish.

Like nylon, the filaments in the better polyster brushes are tapered for springiness and flexibility, and they have flagged tips to provide smooth and uniform application of the paint.

The one advantage nylon has over polyester is that it will wear longer, especially on abrasive surfaces. Some manufacturers make a top quality line of paintbrushes that use both nylon and polyester; the longest bristles are nylon so they absorb most of the wear at the tip, while the remaining bristles are polyester to provide resistance to softening and swelling that can occur with nylon.

Whatever the type used, a good brush has very loose bristles-a few may come out when you shake or spin it, but this should not continue for long. It also should have a high percentage of bristles with flagged tips (hold the tips to the light to check for this).

The brush should be well-stocked with bristles of varying lengths, and there should be one or two wood or plastic plugs of moderate size in the center when you separate the bristles-not a big hollow spot that makes the brush look thick on the outside. The bristles should feel springy but not stiff, and when the tips are pressed against a flat surface, they should fan out easily to a clean, sharp edge that will be easy to control.

The brush size should be comfortable to work with on the surfaces you will be painting, but avoid using a brush that is any smaller than necessary. A larger brush will put the paint on with few strokes and with less chance of brush marks. Generally, you will want to save your best brushes for varnish and enamel, and you should avoid using the same brushes for oil base paints and latex paints.

Nothing ruins a brush more quickly than failure to clean it properly after each use, and it should be done immediately after the painting job is done. This is particularly important with latex paints because they dry faster than oil paints and soon cake inside a brush if it isn't cleaned promptly.

The first step in cleaning a paintbrush is to rub out as much of the paint as possible. Start by wiping vigorously across the rim of the paint can, then wipe the bristles on a stack of old newspaper, tearing off the top sheet as it becomes saturated. If the brush has been used in latex paint, the next step is to wash it thoroughly in a bucket of warm water and detergent, working the bristles with your fingers to get the paint out of the inside and to make sure none is left in the hell of the brush. Rinse the brush in a stream of water to flush the suds away, and to remove the last traces of paint, then spin the handle between the palms of your hands while holding the bristles inside a pail to get rid of the water.

If the brush was used in oil-based paint, you will have to rinse in the appropriate thinner for that paint, after having rubbed out as much as possible in the manner described above. To avoid wasting thinner, wash the brush in several baths, using only a small amount in the bottom of the pail or can each time.

The trick is to pour in a small amount of thinner, then work the bristles vigorously in this by pressing back and forth against the bottom and sides of the container, or by using your fingers (wear rubber gloves). Wipe the excess thinner out of the brush, discard the dirty solution and add fresh thinner to the can. Repeat this two or three times until no more pigment washes out and thinner stays almost clear. Then, if you won't be using the brush for a while, wash it in warm detergent and water and shake or spin it to remove excess water.

After a paintbrush is cleaned, it's a good idea to comb the bristles to remove tangles and restore the original shape. Then wrap the brush in aluminium foil or brown wrapping paper and store it in a dry place. CAPTION: Picture, Combing untangles paintbrush.