Logwood

I used the traditional dye Logwood for the first time recently. Historically this dye was very important, especially as a source of navy blue (obtained with potassium bichrome mordant) from 1800 onwards, but I find when I talk to people who aren't dyers that while they have heard of woad, indigo and madder, this and many other natural dyes have slipped out of general knowledge. Jill Goodwin in A Dyers Manual says Logwood, from the south american native tree Haematoxylon campecianum was known in England from the time of Queen Elizabeth I, but its use was prohibited by law until 1661, as dyers needed to learn to how use mordants to make this dye lasting. The chips of logwood sold as dyestuff come from the heartwood of the tree, which is cut down when about 10 years old. Rita Adrosko in Natural Dyes and Home Dyeing and Rita Buchanan in A Dyers Garden both recommend soaking the logwood chips for at least a few days as fermentation that occurs when the logwood is soaked leads to better results. Rita Buchanan says the choice of mordant is important because logwood does not last long when alum or tannins are used, and best results are obtained when using chrome or iron.

I wish I'd read these books before I did this work with logwood, as I've used only alum mordant and also hadn't seen that Jill Goodwin recommends the dyer to stop heating the dyebath when the wool is added for best, clearest colour.

Here are the results of my experiment, the wool my usual superwashed merino, the mordant my usual pre-mordant of 10% alum (potassium aluminium sulphate) and 8% cream of tartar (potassium hydrogen tartrate). Progressively lighter shades were obtained from the same dyebath, until I ran out of wool.




The next photo shows how one of those magical dyebath transformations has occured - see how the colour of the dyebath the wool went into, and the first colour shown by the wool in the dyebath, was most definitely orange.