Jacopo Tintoretto (1518-1594) employed an unusual painting style that not only irritated the viewing habits of his contemporaries but has also remained a significant aspect of the discourse surrounding the work of the Venetian artist to this day. His unique painting technique opened up entirely new modes of representation and thus also created new areas of design, as reflected in the art theory of the Cinquecento. A precise examination of his painting technique necessitates a detailed inquiry into the material findings. Contrary to the canonized form of composition that emerged in Florence, Tintoretto developed his own unconventional working method. He defied the practices of the painter's guild by leaving traces of craftsmanship visible, allowing the working process to be apparent even in completed works through the brushwork. In doing so, he dissolved Florentine ideals of order, a transgression that was met with misunderstanding by critics. What Tintoretto gained was a new form of image and expression: the visible brushwork conveyed the effects demanded by art theory in an unusual manner. This study reconstructs Tintoretto's working process using painting technology. From the material composition of the supports to the priming techniques and the visibility of preliminary sketches, as well as the application of color, the painter's working method is traced. The reader is given the opportunity to look over Tintoretto's shoulder during the act of painting. The composition of well-known paintings from Berlin, Dresden, Munich, and Vienna is analyzed and related to the parameters of contemporary art criticism.