Last Updated: Aug 10, 2017 Views: 42
To my knowledge, late 17-early 18th century Venetian reticello glass objects always have bubbles trapped at the intersections where four canes cross. The bubbles are nearly always square, rectangular with pointed corners-rather pillow-shaped usually.
Some contemporary glass makers prefer that the bubbles be spherical: Dante Marioni, for example.
Reticello can, with extra effort, be made bubble-free: this involves extra reheating and marvering to make both surfaces of the two elements perfectly smooth before fusing them together.
Additionally, Bill Gudenrath has a website on The Techniques of Renaissance Venetian Glassworking, which features high-quality images and videos on 35 techniques. The video embedded below shows Bill at work making a reticello platter.