A pair of opaline glass vases

Pair of white opaline vases, lined dark blue.
Baluster shape with high neck and resting on a pedestal. On a blue background, a large cartourche is deployed in the center of the vase, it is framed by scrollwork and golden threads, and contains a large bouquet of flowers.
Glass opalisation obtained by the adjonction of tin oxide was well known at Venise since the 16th century. Progressivly opalisation gained the rest of Europa but it was in France around 1810, that it was applicated at a glass made of lead, elaborated in England at the 18th century : the cristal.
Opal cristal fashion was at its peak on 1824 but it continued during the 19th century. Material, forms, decors changed with the years; evolution orderered by the one of the decorative forms and by the technique progress of cristal industry.
Flowers to natural and in polychromy are the principal element of most opaline decor. On some piece of the years 1840-1850, these flowers are accompanied by elaborate gilding. Gilding and flowers continue to be used simultaneously during the following years.
This pair of vases could be attributed to Baccarat as the factory had created a dark blue of their own, made in imitation of Sevres blue but lighter than the latter.
These vases may have been decorated by Jean-François Robert.
Jean-Francois Robert, born in 1778, he worked in the Porcelain Manufactory of Sevres in 1806 and he was on the statements of staff until 1843, when he retired.
So he created with someone called Quinconce, a decoration workshop of crystal and glassware. This workshop was based in Sevres near the factory. The same year, Launay, Hautin and Co. , Trustees of Bercy, Choisy, Baccarat and Saint Louis get into parternship with Robert. He became their only designer. This association ended in 1855, when Jean-François Robert sixty-three years old, was finally retired. The process created by Robert uses colors that are metal oxides and flux mixture, these are very fusible. The decor is painted on the piece with a brush using a stencil or freehand. The object is decorated, then placed in an oven and heated to the desired temperature so that colors and metal applications will vitrify and become part of the surface of the object.
Until 1850 all glazed decorations on Baccarat and St. Louis crystal are the work of Jean-François Robert or his workshop, but this is more true after because the Robert’s process has been popularized and his decors widely imitated.

Bibliography:Y. Amic, L'opaline française au XIXème siècle, Paris, 1952, ed. Gründ