 In recent years, some researchers on Porta’s optics have emphasized that this was not necessarily a shortcoming. Porta’s hard work to improve and investigate the qualities of optical devices with the potential to create marvel generated not only some important discoveries, it also contributed to optical theory. The problem of the relationship between the point of inversion and the focal point in curved mirrors is a case in point, because Porta’s work contributed to the emergence of the concept of virtual and real images (Borrelli 2014, 2017). In this case, Porta’s hands-on approach proved particularly fruitful as it successfully translated artisanal knowledge to the domain of literary culture of the sixteenth century. This was highly innovative, because optical theorists still were largely ignorant of the heuristic potential of the new artifacts produced from cristallo, or Venetian soda glass.