NEW YORK — Sportswear manufacturers — from designer to junior — say they’re facing the official opening of the summer market this week in an energized mood.

Spring bookings at a number of firms have shown at least moderate increases, and vendors who have already moved into summer report orders are up. An increased focus on wear-now merchandising is helping to give the short summer-delivery period more impact.

While white and neutrals are still the big story in designer, silver has added some flash. In the contemporary and junior markets, color and ethnic prints will give the retailer more options. As for hemlines, short is the top trend.

Reflecting the wear-now strategy, the Donna Karan Collection comprises pieces that are “summer necessities,” said the company. Cotton poplin, matte jersey and silk taffeta are Karan’s fabric choices for summer, which begins booking this week.

Calvin Klein Collection’s summer bookings open in about a week, said Susan Sokol, president of Collection. She expects orders to be up about 10 percent over last year.

“The summer season is growing for us, in terms of sales. It’s definitely wear-now, wear-to-the-office summer clothes,” she said.

Klein ships summer from mid-April through May. After that, Sokol maintains, the designer customer is thinking about her fall wardrobe. Denise Seegal, president of DKNY, said that summer bookings, which are complete, were up about 10 percent over last year, driven by white, navy and silver sportswear looks and activewear pieces for warm-weather wear. Particularly strong sellers were the overall dresses with metal hardware, said Seegal, and the stretch active items, including the long lightweight nylon anoraks.

Andrew Rosen, president of Anne Klein & Co., said that since spring business for Collection was up strongly over last year, he’s looking forward to summer “having the same momentum.”

He noted that of the firm’s two bridge divisions, Anne Klein II’s summer business is up just slightly A Line Anne Klein, the more casual division that focuses on items, could see bookings double over last year, he said, because of the importance of items in summer selling.

Tahari’s late spring bookings are up substantially over last year, said Tom Murry, president. Its true summer group is shipped in April, said Murry, but a May delivery was added this year, because he felt the company was otherwise missing out on wear-now summer purchases.

Following the success of an exclusive resort program for Bergdorf Goodman and Neiman Marcus, Todd Oldham is doing an exclusive summer-transition collection for the two retailers. Tony Longoria, Oldham’s partner, said the group will be in fabrics similar to those used for spring, but in colors that will carry into fall.

Longoria said summer bookings were expected to be up significantly over last year for Times 7, the secondary line, because it is currently retailing well.

Bookings have been healthy through spring for better, contemporary and junior sportswear resources, and these firms are expecting to be busy when the summer market opens this week.

Robert Abajian, senior vice president and sportswear designer at Liz Claiborne, noted that vests and ethnic influences, in prints or embellishments, were strong in spring and will carry through to summer.

“People want to buy something they can mix in with other pieces they already have,” he said, “which is good because, if they buy like that, they buy more consistently.”

Monica Belag Forman, president of Kenar Studio, a division of Kenar Enterprises, said she’s expecting summer to be “a huge shipping period.”

“I think the customer wants to buy when the weather is changing,” she said.

With new patchwork and paisley prints and a bigger push for short-shorts in the works, a spokeswoman for Guess said the company is expecting bigger orders over last year.

Likewise for junior firm Necessary Objects, said president Ady Gluck-Frankel.

“We’re really working with stores and generating volume with outfits, giving [stores] six to eight key pieces,” she said.