Glassmaking in renaissance Italy: The innovation of venetian cristallo

Conclusion

The incremental incorporation of new processing steps in the 1450s allowed Venetian cristallo glass to be made in response to perceived consumer demand. The purification of the alume catino ash was the key that allowed cristallo production in the 15th and 16th centuries. However, other steps were involved: the careful selection of a source for SiO₂, the addition of the proper amount of MnO, the use of a fritting process to overcome the limitations imposed by the temperatures attainable in a wood-fired furnace, the process of passing the glass melt several times through water, careful and sustained stirring of the melt, and conscientious attention paid to furnace maintenance. Most of these steps had been employed in the Venetian glass industry since the 14th century, and their use allowed the Venetians to produce a reasonably high-quality vitrum blanchum glass before cristallo was made.

This is not to suggest that the process of invention and innovation was a linear progression of increasingly successful steps. It is more reasonable to suppose that a variety of steps were tried and discarded because of their lack of utility. Unfortunately, incomplete information and gaps in the archaeological and documentary records do not currently allow for the complete reconstruction of the technological “blind alleys” that were wandered in to and out of by Renaissance glassmakers.