The technique of "fenestrado", "plique-a-jour" in French, means "Daylight", or also called "stained glass" for its aesthetic resemblance to stained glass windows, is considered the most complex technique of enamel in jewelry: the enamel is suspended in the alveoli or hollow thanks to the surface tension of the distilled water containing the enamel, lacking this base or metal bottom that holds it , and must be placed very dry in the oven to cook at 780-800oC in a few minutes.
It is an enamel technique that allows the enamel to be placed giving the appearance of a stained glass window, i.e. a transparency that lets in the light.
Its main quality and the characteristic that makes it so precious is that it lets light pass through the enamels, creating a really beautiful and surprising effect.
The realization of this type of pieces is slower than other works, so the value of these pieces lies in the high technical quality of the craftsman.
This type of enamel is characteristic of Modernism and its main exponent is found in René Lalique.