Naphthoquinones, these are wonderful stable yellows and browns. Unlike Flavonoids, there are not many plant species that contain naphthoquinone.
Naphthoquinone subgroups are;
Plumbagin (walnut drupes, Indian leadwort)
Juglone, found in all species of the walnut family (Juglandaceae). This includes trees such as black walnut, butternut, hickories and pecan. Black walnut hulls have the highest concentration of juglone.
Juglone from walnut trees itself is toxic to plants, so much so, that there are only a few plants that are able to grow in its' proximity. The phenomenon of trees that use toxins to stunt competing trees' growth is called allelopathy.
All juglone containing trees are great for natural dyeing and also a great fit for eco printing. Pecan leaf botanical prints are my personal favourites on all types of fabric.
The walnut and pecan leaves have a lot of tannins, and their prints tend to turn darker over time. Dyeing with walnut and pecan hulls or leaves do not require a mordant at all, when you do mordant with alum it will bring out more of the golden tones and mordanting with copper will bring out rich darker golden hues. Post mordant with ferrous sulfate for dark brown to black shades. Fermented black walnut hulls with ferrous sulfate and gom arabic make for a great lightfast ink.
Lawsone aka hennotannic acid: henna (Lawsonia inermis).
Traditionally used for temporary tattoos and hair dye it will turn orange when it is oxidizing on protein (such as the skin of your hands, or hair).
Henna needs no mordant for dyeing. It works better with an acidic dye bath (just add a bit if lemon juice), and will continue to develop its color well after dyeing, turning more saturated under the influence of light and warmth. This is because henna’s dye molecule, lawsone, oxidizes. This means that it reacts with the oxygen in the air to achieve its final, stable state. When henna powder is mixed with an acid, the precursor of the lawsone molecule is released in an intermediary state, ready to attach itself to something. This molecule is called an aglycone.
Henna can be used with the Low Impact Dye technique using only a sludge and manually working it into the fabric as opposed to making a dye bath.
Another way henna is used is as a reducing agent in an organic indigo vat.
Achieving black on wool with henna and green indigo; first step; use henna in an acidic dye bath for a few hours. Second step; apply green indigo with the Low Impact method on the rinsed fabric and let it sit for a good 30 minutes in the indigo sludge.
Alkannin (Alkanet)
Alkanet (Alkanna tinctoria) is a herb in the borage family. The roots are used to extract red and purple dye called alkannin (anchusic acid). The plant is also known as dyers' bugloss, orchanet, Spanish bugloss, or Languedoc bugloss. It is native to the Mediterranean region and actually grows freely in the green patches behind our community.
Alkanet has a rich history of being used as a colorant for make up and ointments because it is easy to dissolve it in fatty substances, and is still being used as such by companies such as Lush.
To extract the colorants of the alkanet roots for textile dyeing you use 35-70% alcohol to extract reds and purples, but I have had better results letting it ferment (I simply forgot the vessel with alkanet bits on my balcony after getting annoyed with the extraction process).
Alkanet roots contain naphthoquinones but it is not very lightfast and you should always apply plenty of alum based mordants before dyeing for purples and reds, and ferrous sulfate for greys.
Articles used for research;
[Naphthoquinones and their pharmacological properties]
The Study of Naphthoquinones and Their Complexes with DNA by Using Raman Spectroscopy and Surface Enhanced Raman Spectroscopy: New Insight into Interactions of DNA with Plant Secondary Metabolites
Veronika Vaverkovab,1 Oldrich Vrana,2 Vojtech Adam,3 Tomas Pekarek,4 Josef Jampilek,5 and Petr Babula
Dominique Cardon; Natural Dyes