Until as recently as the 1950s, connoisseurship was the most important basis for the authentication of artwork. Even though connoisseurship may be based on experience, many experts and scholars do not always agree. The opinions of connoisseurs are also susceptible to change, often based on new evidence, further reflection and study, or simply second thoughts. Connoisseurship is not a ‘finite’ science, but the art world still relies heavily on the opinions of experts...