[en] During the nineteenth century, a period rich in inventions and technical discoveries, the revival of stained glass followed by its industrialization and transformation into an applied art, led to the promotion and development of new glass decoration processes, which in turn led to new products. Among these novelties, muslin glass is the most representative expression. While domestic stained-glass was becoming fashionable, the question became how to find an inexpensive way to make ornamental glass within the reach of the public's budget. One of the solutions to this demand was to print repetitive patterns onto ordinary glass panes by frosting. Frosting consists in removing shine to make a surface matte. But, as far as glass is concerned, one does not simply remove shine, because frosting glass removes at the same time one of its main qualities: transparency. Though frosted glass loses its transparency, it does not lose its translucency, allowing it to veil what is inside from what is outside, while still letting light pass. The charm of muslin glass resided precisely in this game between the transparency and translucency which composed its ornamentation. For those who could not afford stained glass, frosted glass was an interesting and less expensive alternative, as well as representing for architects a new aesthetic option to sift light. Demand for frosted glass in buildings was rapidly increasing for the decoration of vestibules, bathrooms, verandas and other areas for which a particular style was desired. These panes were known as "frosted glass with eyelet drawings" or "muslin glass" or even "tulle glass". They were so called because those who conceived it sought to imitate embroidered curtains in muslin, tulle, or lace. Moreover, they often used this kind of textile as a stencil to decorate on the glass. Challenged with growing demand, glassmaker-painters and glass decorators developed more efficient production systems for muslin glass, many of which were the subject of patents. By analyzing several of these patents we will trace the evolution of the various techniques of printing and frosting glass.

[fr] Au cours du XIXe siècle, la renaissance du vitrail, puis son industrialisation et sa reconversion dans les arts décoratifs, ont favorisé le développement de nouveaux procédés de décoration sur verre, et l'apparition de nouveaux produits. Obtenu en imprimant des motifs répétitifs sur le verre à vitre ordinaire par dépolissage, le verre mousseline en est l'expression la plus représentative. Le verre dépoli perd sa transparence mais non sa translucidité, ce qui lui permet de voiler les intérieurs tout en laissant passer la lumière. Le charme du verre mousseline réside justement dans ce jeu entre transparence et translucidité qui compose son ornementation. Pour ceux qui n'ont pas les moyens de s'offrir un vitrail, c'est une alternative de décoration intéressante et abordable, et pour les architectes, une nouvelle option esthétique pour tamiser la lumière. La demande s'est donc envolée, dans la construction, pour la décoration de vestibules, salles de bain, vérandas et autres espaces auxquels on voulait donner un certain style. Face à la demande grandissante, les peintres-verriers et les décorateurs sur verre mirent au point des systèmes de production de verre mousseline plus performants, dont beaucoup firent l'objet de brevets d'invention. Par l'analyse de plusieurs de ces brevets, nous retraçons l'évolution des diverses techniques d'impression et de dépolissage du verre.