For much of the twentieth century, attributing an unsigned old-master painting to a particular workshop or artist rested primarily on connoisseurship: the trained eye of an expert who had studied enough authenticated works by a given hand to recognize characteristic brushwork, proportion, and compositional habit, even in the absence of documentary evidence. Connoisseurs' judgments, while often accurate, could not be independently verified by anyone lacking the same trained eye, and different connoisseurs sometimes reached opposing conclusions about the same painting. Technical analysis, pigment dating, X-radiography of underdrawing, dendrochronology of wooden panels, introduced evidence that could be checked by any qualified laboratory, regardless of who conducted the original attribution. A pigment unavailable before a certain date, for instance, can rule out an attribution to an earlier artist regardless of how confidently a connoisseur had endorsed it. Several attributions accepted for decades on connoisseurship alone have since been revised once technical analysis dated the panel or pigments to a period after the proposed artist's death. Yet technical analysis has not displaced connoisseurship so much as constrained it. Dating a panel to the correct period narrows the range of possible attributions but rarely narrows it to a single artist, since many painters in a workshop tradition used materials of the same origin and period; distinguishing among them still typically requires the kind of stylistic judgment that only trained connoisseurship provides. The two methods, in current practice, function as sequential filters rather than as competitors.