Lamentation over dead Christ. Reverse painting on glass, oil painting on glass, East European school Sandl Upper Austria, late 18th century. Measurements with frame: h 33 x 24 cm The painting of icons on glass followed a procedure that should rather be defined as painting 'under' glass. The painter in fact drew and colored the icon on what, when finished, would be the back of the glass plate (mostly produced by hand in small local glass factories), while the opposite part, exposed to the eye of the observer, acted as a protective screen. This procedure meant that the contours were drawn in reverse so that, once the glass was turned, the image would appear correctly. The first phase was the drawing of the contours using a thin brush, then the coloring of the parts of the figures and the background was carried out; in certain cases and regions, a thin film of gold or silver color was also used. At the end, after a brushstroke of paint on the background to preserve it from moisture, the painting was framed and protected on the back by a wooden panel.