North Carolina writer Nan Chase (nanchase@bellsouth.net) often reports on home furnishings.

Far from being just a decorative afterthought, window treatments in a home office can improve productivity.

"One of the most common mistakes people make is not choosing a window treatment that can provide varying degrees of light control," says Suzy Watkins of Sterling Design Group in Warrenton.

The sun's glare can render work on computer screens nearly invisible and lead to eyestrain. Blinds, rollers, shutters, protective films, and specialty glass offer solutions for any home office.

Here's a guide to choosing the right window coverings:

Shades. Economical and versatile, shades offer various degrees of light diffusion and can be custom ordered.

The main drawback--whether you have elegant Roman shades, durable honeycomb shades, sleek rollers, or textural wood or woven grass--is that they are either open or closed, offering less flexibility as the sun moves. That's why many decorators suggest installing shades with dual top-down/bottom-up openers that allow some natural light while blocking the sun.

Shades come in sheer, semisheer, or blackout weights, and the blackout materials really work. If your home office is in an apartment complex or condominium, you might want to check regulations to see if the exterior surface must be white. That's an option with many shades, including honeycomb or roller blackout shades.

"Honeycombs come in lots of colors and different sizes--from a pleat that is 3/8-inch wide all the way to three inches," says Elinor Ascher of Elinor Ascher Designs in Silver Spring. "The larger the pleat, the more elegant it looks."

Blinds. Blinds all have slats, but a range of materials lets you customize. Traditional Venetian blinds come in wood, metal, and composites; widths vary from one inch to 25/8 inches (heavier blinds are harder to operate). Wood blinds, whether painted or stained, are good-looking, long-lasting, and pricey. Affordable metal comes in hundreds of colors, while composite materials work in high-humidity areas.

Designers customize blinds by using contrasting color or pattern for the cloth trim. They sometimes vary the mounting position--inside the window casing, alongside, or fully outside--depending on window depth and any additional treatments. For blinds on high windows, power controls may be necessary.

"Privacy sheer" blinds, with slats made of lightweight fabric instead of wood or metal, get raves. They function like standard blinds but create a softer feel because all parts are fabric. Designers recommend Silhouette by Hunter Douglas (hunterdouglas.com). They're more expensive than other treatments, says designer Nancy Colbert, but fit into many decors and can stand alone.

Wooden or composite plantation shutters offer a high degree of privacy on lower windows and can be customized using fabric in place of wooden slats.

Glass treatments. Sometimes the best window treatment is none at all. In that case, consider using a transparent film by 3M or Vista Window Film. According to the International Window Film Association, products such as those eliminate almost all damaging ultraviolet light and glare. They can also save on heating and cooling costs and protect glass against shattering.

If you don't need all the windows to open, glass block can liven up otherwise ordinary window space by bending light in interesting ways while providing a measure of privacy. If window glass predominates in the decor, use extra rugs to help muffle sound.