The wood is immersed for 48 hours in a warm solution of alum and sprinkled several times with the following mixture : One part of logwood of the best quality is boiled with 10 parts of water, then it is filtered through linen and the liquid evaporated at a low temperature until its volume is reduced by one-half. To every quart of this bath are added 10 to 15 drops of a saturate of soluble indigo entirely neutral in reaction.

Smaller pieces may be steeped for a time in this solution, then the wood is rubbed with a saturated and filtered solution of verdigris in warm, concentrated acetic acid, and this operation continued until a black color of the desired intensity is obtained. The oak wood dyed in this manner is very similar to real ebony.