Introduction; Logwood, haematoxylon campechianum, member of the pea family. Once it was super popular, then it became forbidden for use because it was not light fast by Queen Elizabeth I of Engeland in 1581.
Can we use it in good faith as a natural dye? I believe we can, but good mordanting is the key to succes, and knowing where to use it for.
I would not use it for upper body clothes, as sweat can cause unsightly stains. I would not use it for a wall hanging, as it will shift colour.
I would definitely use it for a skirt, or a scarf, and perhaps a pillow case if it is not in direct sunlight. The colours are just way too pretty to pass up on!
Chips or sawdust?
Logwood is available in chips, and in sawdust. The chips are the cheapest and available in lots of stores and around the internet. I have the sawdust on my site, which is 30% stronger in use, because it is much better oxidised to than the chips. So if you see a recipe talking about 30% Weight Of Fibre (WOF) logwood chips you would need only 20%WOF of the sawdust. The other thing I prefer about sawdust is that I do not need to put it in a bag to use for dyeing. The chips tend to make dye spots, and other streaks, unless you put them in a stocking or netting while dyeing. The powder does not have this issue.
Mordanting like a pro.
The ultimate colour of your piece dyed with logwood, depends on mordanting and the PH of your dye water. You must scour and mordant all your fabrics very, very well!
Using alum will always bring out the purples in the fabric.
Using copper will bring out the blues.
Using ferrous sulfate will bring out the darker shades of purple when you use it as a post mordant (modifier). Using it as a mordant will give you greys and blacks!.
I have read a LOT of books on the subject. From the fascinating Edward Bancroft to J.N. Liles to Jenny Dean and then some, some authors are super specific, but use additives I do not think have a place in a home studio as most dyers have today. My rule; if I can't spell it I probably should not be using it, until I have my fully equipped studio with a hood. Other recipes are surprisingly vague, "use 10-50%WOF for medium depth of shade" is amazingly random for a professional dye book and I love precise.
These recipes are after trial and much error, use materials that are easily available and are not toxic in use. This doesn't mean you should drink it...
As always; use dedicated utensils and work outside or in a well ventilated room. Do not eat and drink or prepare food next to your dye projects.
If you know my works I try to save water where I can. I will wet out fabrics and use the water for the dye or the mordant bath without hesitation. I use in general less water than is recommended by the books, but I work the fibres more, making sure the dye uptake is even, even when they can float freely. I use an old 5 liter pasta pan for most of my dyeing and that can dye up to 150 grams of silk, as long as I turn it well and often.
All dye baths can be re-used for lighter shades. This is when the fun of experimenting starts; re-warm the dye bath, add a little vinegar, or a bit of soda ash and look at the colours shift!
Mordant silk with 1-2% WOF of copper sulfate, I use a cold mordant and leave overnight. the fabric will be light blue the next day. The sample on the left was done with 1%WOF copper sulfate, using 2 would increase light-fastness. I know some people think copper sulfate is a 'bad' mordant but it is used in agriculture, and according to my research you have to ingest quite a bit for it to be toxic for your body, and your body would reject it by vomiting. I use small percentages on purpose, that are will not be a burden on the eco system!
Heat 20% WOF logwood powder in plenty of water to about 60ºc, best not to let it get to boiling point. Check Ph to be at least Ph6 or slightly more alkali. If you need to adjust the Ph, add a teaspoon of soda ash, then check again.
Dye the mordanted fabric in the logwood dye for at least an hour, turning regularly.
Rinse after dyeing in regular water with a bit of Ecover Ph Neutral dish washing soap.
Logwood Fierce Deep Purple
Mordant your protein fabrics with 20% alum overnight in a cold bath, or for about an hour in a warm bath.
Make a dye bath with 20%WOF logwood powder, warm the bath to 60ºc and keep the Ph at around Ph5.5.
More alkali may turn the dye to a blue shade, and more acid will turn to a coppery brown. I know the books say to make your dye bath and then add wetted fibres but for logwood I often add the wetted fabric and just go with it, works fine so far. The longer you leave it in, the better, but make sure you keep the textile submerged or you will get unsightly patches!
Mordant your fibres with 1%WOF Ferrous Sulphate for protein fibres and 1.5%WOF for cellulose for at least an hour but not overnight as it will harm your textiles!
Proceed to make a dye bath as before, with 20%WOF logwood powder and dye your fabrics. By shifting the Ph to alkaline with 1 teaspoon of soda ash per liter of water you will get a more steel blue grey, keep the Ph 5.5 for middle grey.
It is totally possible to make just 1 dye bath and enter well mordanted textiles with different mordants at once. You can only do this if you have rinsed your textiles very, very well after mordanting! I often work like this when I want to make plenty of different, but small samples and I can't justify making separate dye baths for each 30 grams of textile.
For a complete tutorial on eco printing using logwood, with discharge effect, look here.
Please share your results on our Facebook group called BotanicalPrint Group
It's an amazing group of passionate dyers and printers and there is so much to learn there!