The small bottle shown in this video is made with bands of color. Learn more in The Techniques of Renaissance Venetian Glassworking by William Gudenrath http://renvenetian.cmog.org/chapter/later-first-century-bc-evidence
The Venetian glass industry enjoyed a golden age during the Renaissance. By the early 1500s, the wonders of Venetian glass were well known throughout western Europe. Not well known, however, was how these objects were made. Until now. The result of 30+ years of research by William Gudenrath, The Techniques of Renaissance Venetian Glassworking – http://renvenetian.cmog.org – presents 35 complete reconstructions of Venetian glassmaking techniques through detailed 360˚ photography and high-definition video.