Frames and supports in 15th and 16th-century Southern Netherlandish painting

MATERIALS AND MEN 21 94. Fraiture 2011b, 0-10. 95. Communication by Jean-Albert Glatigny. 96. Examination of the sapwood in a hundred oaks in northern Poland gives a median value of 15 rings of sapwood, with 50% of the values between 13 and 19. For oak from Germany and the Netherlands, a median value of 17 rings was determined with 50% of the values between 13 and 22. Quoted from Klein 1986, 229. 97. Klein 1982, 253-271. 98. Klein 1987, 29-40. 99. Klein 1989a, 171-172. 100. Bauch et al. 1974, 32-40. interval between the dendrochronological result and the known or estimated date of utilization. 94 A possible pitfall may lie in the assumption, in the above-cited calculations, that sapwood only was removed. On freshly cut oak it is difficult to judge the borderline between sapwood and hardwood, which becomes better visible as the wood dries. 95 The woodcutters, no doubt under instructions to remove all sapwood, may well have preferred to err on the safe side and remove a few rings of hardwood as well. For the 15th century, several dendrochronological studies on paintings point to a period of upwards of 10 years between the felling and the use of the wood. This figure is deduced from paintings of known date as follows: a length of time is calculated between the most recent datable ring and the known painting date. From this figure is then deducted number of years for the sapwood which was removed. A figure of 13 to 19 years for the sapwood has been put forward. 96 Peter Klein has suggested a waiting period of 10 to 15 years. 97 In two wings of the Last Judgement and Annunciation by Petrus Christus (Berlin, Staatliche Museen, Gemäldegalerie, inv. no. 529 A-B), there appears to have been an interval of between 14 and 20 years between the felling of the tree and the use of the wood. 98 In the case of wings of the Triptych of the Last Supper by Dirk Bouts, 1464 (Leuven, Church of St Peter), the most recent heartwood growth rings date to 1436, i.e. 28 years before the completion of the painting. Deducting from this 13 to 19 years of sapwood for a fully-grown tree, this gives a period between felling and use (drying, transportation, holding in stock) of between 9 and 15 years, for a fully-grown tree (258 measured growth rings). 99 According to dendrochronologists, the gap between the felling of the tree and the use of wood as a painting support was reduced by between 4 and 12 years in the 16th and 17th centuries. 100 Economic logic probably required a faster turnaround. Uncertainties thus remain in calculating the interval between the felling of the tree and the use of the boards for painting.