We find a symbolic case in white pigments that, being opaque as a rule, cannot be used as such or to lighten other pigments. These effects are obtained, as with watercolours, by dilution or by simply leaving the white canvas. We can easily imagine that the subjects can neither be corrected nor changed once they are sketched on the canvas, and considering the fineness of the foundation layer, a part that has already been painted cannot even be mechanically removed.
We know little about the origins of this technique. Perhaps the oldest evidence lies in the so-called Manuscript of Bologna, (corsivo) of the 15th century. Recipes 214, 215 and 216 discuss about painting parchment or linen canvas “che parerà vetrio naturali” (that will look like natural glass) by impregnating them with egg white and gum arabic, and then painting it all with “liquid paint” or with a mixture made up of linseed and a natural resin, such as mastic or sandarac. Even St. Serious in 1535 and A. T. De Mayerne in 1620-46 mention translucent paintings but it is J. M. Cröker who, in 1736, gives us a description of the many short-lived decorations that were prepared for feasts, processions, coronation ceremonies and funerals, also providing diagrams of frames for paintings presenting various shapes, with bases for candles and holes to light them. The descriptions include arches, columns, pyramids, etc.
Towards the late 18th century, translucent painting becomes a genre per se and an actual trend, particularly among North European artists. We can mention P. Hackert, Carmotelle, A. Nussenthaler, T. Gainsborough, and artists up to the period of C. D. Friedrich. Hence, we observe how the “Trasparenti” of Mendrisio are part of a broader framework of which there is, unfortunately, very little direct evidence because it was mainly a technique intended for temporary fittings.
Since it is a living tradition that is handed down, the materials, particularly pigments and solvents, have been adapted to suit technical evolution, thus facilitating the work to artists and offering extremely interesting expressive opportunities.