Key conservation issues: splits in the wood - 保存修復上の主要課題:木地の亀裂

Key conservation issues: splits in the wood - 保存修復上の主要課題:木地の亀裂

This image shows the split along the left hand side of the lid of the Mazarin Chest. Splits in the lid were caused by a combination of the construction method used to make the wooden carcase and fluctuations in relative humidity (RH).

この写真はマザラン・チェストの蓋左側に入った亀裂を示します。蓋の亀裂は木地構造と相対湿度の変化が組み合わさって起こったものです。

Wood expands and contracts in response to changes in RH. The greater the frequency and the greater the range that RH fluctuates, the more the wood moves in response. However, wood only expands and contracts across the grain, not along it. The boards across the middle of the lid shrink and expand from front to back, whilst the cleats (hashibami) attached along their ends do not. The split along the joint line between the boards and cleats is the result of this differential movement in the wooden substrate.

木材は相対湿度の変動に応じて膨張収縮します。湿度の変動の頻度と幅が大きければ大きいほど木の動きも大きくなります。しかし膨縮は、木目に沿ってではなく、それに垂直にしか起こりません。蓋の中央を走る複数の木板は横に膨縮するのに対し、それらの端を止める端喰は動きません。この木地の動きの違いにより板と端喰の接合部に沿って亀裂が入ります。

This image also shows the broken and degraded old gesso (a mixture of animal glue and chalk powder) fills around the corner mount, with associated overpaint covering the original surface.

この写真は隅金具の周りが劣化して脆くなったゲッソ剤(アニマルグルーと石膏粉の混合)で埋められ、元の表面の上に塗料が塗られている様子を示します。