What is the main difference between the press-and-blow and the blow-and-blow shaping processes in glassworking?

The main distinction between the press-and-blow and blow-and-blow shaping processes in glassworking lies in the initial forming techniques they employ. In the press-and-blow method, the glass is first formed by pressing it into a mold, which shapes the glass into a preliminary form. This step utilizes a tool to create an initial shape that is then further refined by blowing air into it, allowing for more intricate details and final adjustments.

This contrasts with the blow-and-blow technique, where the glass is solely shaped by blowing air into it from the beginning, without the prior pressing step. Each method has its unique applications in glassmaking, suitable for different types of glass products, but the key difference is that press-and-blow incorporates that initial pressing stage, enabling specific shapes and designs that require more precise control.

The other options do not accurately capture this foundational difference; pressing is not utilized in the blow-and-blow method, blowing is not the only technique in use for the first process, and while both processes can produce various glass types, that is not the central difference defining their methods.