CALLING ALL VALLI GIRLS: When Giambattista Valli for Impulse Only at Macy’s bows on Oct. 26, the designer will preside over the launch of his first affordably priced collection. Giambattista Valli for Impulse ranges in price from $50 to $150 and will be sold in about 225 Macy’s stores nationwide and on macys.com. An ad campaign for the Impulse collection was photographed at Valli’s Paris atelier, which has an Old World grandeur. Models cavorted in the space on a makeshift mirrored runway. The ads will appear in November issues of national, regional and city magazines, outdoor venues and Macy’s e-commerce site. There will also be an extensive digital campaign.