Bill Blass has been designing bed linens for Springmaid for 20 years now, but he was by no means a pioneer in putting pizazz into pillowcases and sheets.

"Emilio Pucci did a sheet line for them in the 1950s," Blass says.Though the Bill Blass name is more commonly associated with high-fashion American apparel, it has been worth close to $1 billion to the home furnishings world. His designs sold $100 million at retail in 1989, according to Springs Industries, the parent company.

"I have always felt there was a natural relationship between clothes and other products and that fabrics for apparel can often be adapted for the home," says Blass.

This attitude seems to be shared by the general public, which has been responsive to designer names on fabrics, perfume, furniture, domestics and even automobiles.

Blass has been advising Ford Motor Co. for 14 years on colors and fabrics for car interiors. Ten years ago, he told them to move away from metallic threads in upholstery and toward a sporty look to complement the sportswear car owners were wearing.

Among his most successful suggestions for both car interiors and sheets are menswear classics. For Ford he suggested navy and camel interiors. For Springmaid, he designed glen plaid sheets.

Recently, sheet patterns have been short-lived as manufacturers compete with new designs. This emphasis on novelty could be misplaced. In home decorating, as in fashion, Blass says most people are more comfortable with updated classics than with novelties.

"Classics are familiar," he says, "they appeal to us subconsciously."

When they are used in a fresh way, Blass says, they comfort and stimulate at the same time. A good designer, for example, might use those perennial favorites - stripes, polka dots and checks - but use them together to create interest.

Compared with the past decade, Blass says that for the 1990s "I foresee a more classical attitude and simpler patterns. Now that we are making 100 percent cotton sheets, which are more expensive, they have to last longer.

"Unlike clothes, which are changed frequently, the home furnishings tend to persist."

If you're shopping for new sheets, rest assured that you won't outgrow the classics such as toile prints, blue and white stripes, polka dots and mixed floral prints. The eye never tires of these designs. Other perennial sellers, says Blass, are plaids and paisleys, which he revives by changing their colors.

But some colors and patterns, he says, never seem to work: orange and geometric patterns with jagged lines, for example. He also says novelty looks that excite at first, such as cartoon characters on sheets, are the patterns most people tire of fairly quickly.

Blass, who has created between four and five new designs at least twice a year for 20 years, says that sometimes he's been too far ahead of the public for success.

"One of our early efforts in black sheets was a failure," says Blass, "and we did a black, red and white number which was an absolute disaster."