The metalpoint stylus, a writing instrument known to the Romans, was first used in Western art around A D 1100 to rule manuscript texts and lay in illustration designs. Around 1300, artists began to use metalpoint as an independent drawing medium. In the fifteenth century, metalpoint drawing reached its pinnacle at the hands of artists such as Leonard0 da Vinci and Filippino Lippi who wove the fine grey lines into precisely modeled figures, heads and drapery studies.Medieval and Renaissance sources mention metalpoint styli made from silver, gold, copper, lead, lead alloyed with tin or bismuth, and bronze. Metalpoint requires a support prepared with an abrasive ground (typically pigments bound in animal glue), except for lead and its alloys, which can mark plain paper. Despite the variety of metals used, metalpoint types cannot be identified visually. Each metal creates a grey line regardless of its natural colour. Over time, each metal corrodes. The corroded lines may range in colour from black to brown to yellow-gold depending upon the metal type and ageing environment. Silver might corrode to silver sulphide, lead to lead carbonate, lead sulphite or lead sulphate, copper to copper carbonate, and tin may form tin salts. Drawing condition, particularly degree of abrasion, and ground colour also affect the perceived metalpoint tone. Due to such variables, one metal may take on different tones over time just as different metals may take on a similar tone. Within the same drawing, dense areas may appear brown and lighter areas may appear golden. Even lead on an unprepared support is difficult to distinguish from graphite in an old, worn drawing by visual analysis alone.Media descriptions in catalogues and museum labels often list drawings as 'silverpoint' despite a lack ,of objective analysis. The fact that silverpoint is mentioned most often in artists' manuals and historical literature has probably encouraged this generalization. The practice is not new as James Watrous remarked upon erroneous silverpoint designations in The Cruft of Old Master
Drawings, published in 1957.It is possible that the widespread practice of describing all metalpoints on coated paper as silverpoint has led to a misrepresentation of metalpoint use. Identifying the physical composition of metalpoint through objective technical analysis could generate a more precise understanding of metalpoint history. If, in fact, great compositional variation existed as suggested by historical literature, then such information could enhance attribution studies by revealing physical differences in metalpoint character across time periods and geographic regions and between workshops and individual artists.Few studies have been published on metalpoint identification. The earliest, conducted by Watrous, aimed to identify different metalpoints by their changing appearance over time. In the early 1950s he aged samples of silver, copper, brass, bronze, and leadpoint for four years and then recorded their oxidized tonality. Copper and its alloys were described as...