AbstractOn the back of several paintings on panel in the oeuvre of Willem Kalf, the panelmakers mark of Melchior de Bout has been found. Like his father Philip, De Bout was registered in Antwerp as a 'witter ende paneelmaker'. He thus seems to have specialised in producing panels that were covered, on both sides of the wooden support, with a preparatory (ground) layer consisting of chalk and glue. Occasionally, an imprimatura was also applied. De Bout's 'ready-made' panels were not only used by Willem Kalf, but also by Sebastian Stosskopf, Charles Le Brun, Jacques Linard, Lubin Baugin and Willem van Aelst. Since these artists were all working in Paris around the middle of the seventeenth century, it seems justified to conclude that for a certain time, the Antwerp panel maker specifically produced his panels for distribution in the French capital. The popularity of the panels of this highly specialised Antwerp panelmaker illustrates the strong appeal that the dynamic art market in Paris had for artists, art dealers and buyers from France and abroad.