Plant dyeing directory: acid dyes, metal mordants or soy milk?
Dyeing with plants is a relaxing and slow craft but at the same time it is more complicated than most people think. There’s a lot of (mis)information on the internet about what plants you should use and how to best prepare your fibres. It is easy to get lost in the jungle of different recipes and tips, especially when you’re a beginner. As a dyer making a living with my plant dyed work, I research a lot and after years of practice I slowly start to make sense of all the pieces of information I came across so far.
I prepared a simple flow chart to help you avoid mistakes I made when I first started my botanical dyeing journey. Of course this directory is just an overview, and there are a lot more personal preferences to consider (environment, health etc.). I hope it will give you some initial structure, though, and help you understand the dependencies between different fibers, techniques and dye stuffs. Start by answering the questions and following the directions, or go to the diagram version at the bottom of this post.
Please note that this directory only helps you find techniques and plants suitable for your projects but does not describe the whole dyeing process. Regardless of the technique you choose, you should always scour (wash) your fibres prior to dyeing for the best colour uptake. There are no recipes in this blog post, otherwise it would become a very long read (maybe I will bring out a book one day:). If you’re interested in reliable literature on the subject, go to my Pinterest board where I save all the books I recommend.
Q1. What purpose are you dyeing for?
If you are dyeing for business, you want to offer colour fast products. Go to Q2.1
If you are dyeing for personal projects, you can also take it easy. Go to Q2.2
If you are dyeing for healing properties of the plants, skip all the rest and go directly to T7.
Q2. Choose your main objective
Q2.1 Do you mind using metal mordants?
Yes - go to Q3.1
No - go to Q3.2
Q2.2 Is colour fastness important to you?
No - go to Q3.3
Yes - go to Q2.1
Q3. What fibres are you dyeing?
If you want to dye cellulose fibres, go to Technique 1
If you want to dye protein fibres, go to Technique 2 OR Technique 1
If you want to dye cellulose fibres, go to Technique 3
If you want to dye protein fibres, go to Technique 4
If you want to dye cellulose fibres, go to Technique 5
If you want to dye protein fibres, go to Technique 6
Dyeing and mordanting techniques directory
T1. Direct dyes are dyes that don’t require any mordants to attach to the fibre. There’s only a handful of dye stuffs that work without any assist. Indigo forms an insoluble bond with fibres without any mordants and it works best on cellulose fibres, while dyes like walnut, cutch, safflower ect. work best on protein fibres. Run your own colour fastness test on the fabric of your choice and see what works best for you.
T2. Acid dyes are dyes applied at lower pH and work on protein fibres, as they take advantage of protein’s affinity for acids. The acid used in the dye bath is either vinegar or citric acid, the plants that can be used are madder, pomegranate skins, henna, cochineal etc. These colours are very lightfast but can’t be washed hot.
T3. Metal mordants for cellulose like aluminium, iron, copper, tin etc. Metal mordants form a chemical bond between the fibre and the dye stuff, so that the colours stay fixed and don’t detach when rubbed, washed or exposed to sun. There are plenty of different mordanting recipes involving metal mordants, but the most popular ones are Alum + Tannins (two-step hot mordant), Aluminium Acetate (AA cold mordant) and Iron Sulphate (usually used as a post mordant or post modifier after aluminium mordant). Aluminium also brightens the colours, iron saddens them.
T4. Metal mordants for protein call for dedicated recipes. The most common one is Alum mordant (one step, no tannins needed). Iron Sulphate should be used in small quantities, as it might damage protein fibres.
Remember, mordants won’t help if the dyes you use are fugitive. A lot of dye stuffs shared on social media and blogs are not suitable—like red cabbage, beetroot or berries—and fade quickly. If you want reliable and colourfast results, go with traditional dyes recorded in good literature: weld, goldenrod, osage, fustic, madder, cochineal, logwood, lac, cutch, and many many more!
T5. Soy milk is not a mordant but a binder. It makes cellulose fibres act more like protein fibres and enhances the colour uptake. It does not form any chemical bond between the fibre and the dye stuff, though. All the clothes I dye for myself are pretreated with soy milk. I wash them by hand in a luke warm water using ecological soap and I still enjoy lovely colours after a few years. If you work with protein fibres, there is no need to use soy milk. Instead, you can just…
T6. Skip pretreating if you dye protein fibres just for fun and don’t care about light and wash fastness. Wool and silk take up the dyes well without mordants or binders and while the bond between the fibre and the dye will not be strong, it is good enough for those who just want to experiment some and maybe overdue the fibers once the colour changes..
Local dyes and kitchen waste dyes are especially appealing for dyeing novices and suitable for kids projects. They are often not colourfast, but they are easy to obtain and come for free. I highly recommend testing dyes you can find locally. Botanical dyeing is a magical craft and sometimes not knowing what colors you get is half of the thrill, even if the colour might fade later. Remember not to use toxic plants and do your research before you put a new plant into your pot.
T7. Dyeing with medicinal plants is a technique used in ayurvedic practice—you infuse the cloth with healing substances extracted from plants. If you don’t bind the dyes with a mordant, the fabric will slowly release healing powers when rubbing against your skin. You can use medicinal plants like madder, turmeric, tannin-rich dyes, indigo etc. In this practice colour is a secondary outcome.
Thank you for getting so far, I hope that helps!
Just a few words to wrap it up: remember there are always exceptions to the rule! My main tip after you start dyeing with plants (especially for business!) would be to do your own dye uptake and colour fastness tests. There are several factors influencing the outcome, be it water quality, dye stuff quality, how the fabric was manufactured, etc. Your set up and your ingredients will always be unique to you, so get informed, trust the books, but also see how the recipes work for you.
If you decide to dye with metal mordants, please make sure you are using gloves, clothing protecting your skin and a face mask. Have a dedicated set of tools for your craft, don’t inhale the fumes or consume the liquids.
Let me know if this directory helped you in any way. If you have more questions, I’d be happy to answer them and maybe write a few follow-up posts with more details.