A brief history of Logwood for natural dyeing
Logwood and many other natural dyes have been used for hundreds of years to dye textiles. Exploration and discovery of the New World established new trade routes which increased the availability of more exotic colours, Logwood included. Logwood natural dye comes Haemotoxylum Campechianum which comes from central America, particularly Belize. The Latin name of logwood literally means bloodwood.(Haemo meaning blood and xylum meaning wood). It grows as a tree although it is a member of the legume (Pea) botanical family. The heartwood of the tree trunks yields the natural dye colour and historically it was exported as logs for ease of transportation, hence the name, Log Wood.
The chemical colour in Logwood is haemotoxilin which is very sensitive to pH and the mordants used to fix the colour to the fibres. In fact, Queen Elizabeth 1 passed a law banning the import of Logwood because it was thought to not be colourfast. (Such was the importance of natural dyes for the wealth of the nation) However, once it was discovered that the colour can be fixed with alum mordant the trade routes and imports were quickly re-established. (More to read here)
Where does Logwood come from?
Nowadays, most Logwood natural dye comes from central America and the West Indies where it is grown sustainably. It is not an endangered tree and grows abundantly, producing a large amount of seeds. The trees are felled between 8-13m tall, though it is also produced by coppicing the trees. As a dye stuff, it is available as shredded wood chips or as a powder.
What colours can I get and how do I use it?
Range from deep purple and inky blue through violet to mauve and lavender to grey, and also brown.
How do I use it?
Logwood needs a mordant to help the natural dye colour fix to the fibre. This is usually 22% (to weight of fibre) Alum. The wood chips are first soaked then boiled to release the haemotoxilin natural dye colour chemical which needs to oxidise. (BE AWARE: haemotoxilin is poisonous, so don’t breathe in the fumes or steam, or ingest it.) The mixture MUST be strained through a fine plastic sieve or muslin because the tiny splinters of wood can get quickly tangled in the yarn fibres if you don’t! The alum mordant soaked yarn is then simmered in the dye to take up the colour.
Once the yarn is dyed, it needs to be very well rinsed because logwood “slakes” off, meaning any excess dye stuck to the fibres sheds and rinses away. You will get a rich purple coloured yarn. NEVER use utensils for food after you have used them to process dye with.
Logwood is sensitive to pH, so the violet purple colour can be shifted to brown with a squeeze of lemon juice, (Acid, lower pH) and to more inky blue with the addition of a few drops of household ammonia. (Alkali, higher pH). I use pH litmus paper strips to measure the pH of the dye, especially when I want to adjust the colour tone a bit. When rinsing your yarn to get rid of excess colour, use a pH neutral wash liquid. Even a slightly acidic or alkaline solution can change to tint of the yarn.
It can be further adjusted with rusty iron water which alters the colour to grey, sometimes almost black. Most natural dyes exhaust well. This means that you can dye several times from one dye pot, with reducing amounts of colour each time. This can create an ombré effect over the skeins which is lovely in garments.
Where can I buy Logwood natural dye?
In March I developed a range of natural dyes which includes Logwood. The dyes are packaged in eco-pouches, measured to dye at least 100g of yarn or fibre in a solar dye jar or using traditional dye pot methods. The Logwood pouch includes 22% alum mordant to fix the colour, so its’ ready to be used when you receive it, with no weighing or faffing! It may be a powder or as wood chips. Both work in the same way and give beautiful purples and violets on wool and fibre.
Most natural dye suppliers on line sell logwood, just remember you need more mordant (alum) to fix the colour than other dyes, so take this into account when you place your order. Ask questions if you aren’t sure how to use this dye, the supplier should be more than happy to help.
I hope this has inspired you to have a go! If you are still not sure, drop me an email and I’ll do my best to help, or point you in the direction of someone who can.