Murasaki: Purple Gromwell Dyeing.
- Suzanne Dekel
- 6 days ago
- 3 min read
Lithospermum erythrorhizon, a plant species in the genus Lithospermum. Commonly called purple gromwell, red gromwell, red-root gromwell and redroot lithospermum.
Also known as Shikon because the main dye compound is Shikonin, which is the chemical mirror image of the more widely used dye compound alkannin that is found in dyer’s alkanet. Shikonin and alkannin are both naphthoquinones. Both are found in the bark of the roots.
The Japanese word for the plant is murasaki (紫) which means 'purple' and this is what I will refer to in this blog. There are many specific names for specific shades of purple In Japan there are very specific names for very specific shades of purple and I will include part of the visual I found here.
Many of these shades can be made using Lithospermum erythorhizon, the perennial flower has furry stems of about 50cm high. The small flowers are white (as opposed to to the purple flowers of alkannet).
The plant grows wild in mountain regions of Japan, the Korean peninsular and on the grasslands of North East China. It is the dark, purple roots we are after, and like madder, third or fourth year roots are way more potent than first year roots. In Japan the plant has become rare, and picking the plant if forbidden.
Besides being a powerful dye, shikonin has a long history of use in traditional Chinese medicine, and has been studied for its antiviral attributes. Shikone Extract is an antioxidant and has an antimicrobial effect against bacterial infections of the skin and was used to assist wound healing.
Dyeing with Murasaki.
Murasaki has a long history of use in natural dyeing in China, Japan and Korea. The plant was also used in ancient Egypt and Greco-Roman world as a dye.
In this absolute gem of a video you can see the dye process of Murasaki (starting at 4.17') among other dye stuffs. Sachio Yoshioka was the fifth-generation head of the Somenotsukasa Yoshioka dye workshop in Fushimi, southern Kyoto. He has sadly passed away in 2019 but his expertise remains unrivaled.
(And if you want to spend 6$ really really well, rent this video dedicated to Murasaki entirely. Over an hour worth of visual fabulousness.
The old way of dyeing would involve pounding Murasaki roots for a lengthy period with a mallet in a wooden bowl with rice vinegar and hot water.
You HAVE to mordant you fabric (wool or silk) with alum before dyeing, because like alkannet, this dye is not super light fast!
Preparing murasaki dye (from Lithospermum erythrorhizon root pieces) is quite different from other natural dyes—it’s sensitive, precious, and requires low temperatures to preserve its vivid purples.
Here's a step-by-step guide to preparing it properly:
Materials Needed
Dried murasaki root pieces at 50-100% WOF
Ethanol or denatured alcohol (95%)
Distilled water
Non-reactive container (glass or ceramic)
Gloves, mask (optional but recommended)
Fine strainer or muslin cloth
pH strips (optional)
Cold Alcohol Extraction Method
(This method preserves the reddish-purple hues best.)
Pre-soak (optional but helpful)
Lightly crush the murasaki root pieces.
Soak in a small amount of distilled water for 1–2 hours to soften. Discard the water.
Alcohol Extraction
Place the softened root in a glass jar.
Cover with 95% alcohol—just enough to submerge the roots.
Let it extract in the dark, at room temperature for 24–48 hours.
Shake gently once or twice a day.
The liquid will turn deep reddish-purple.
Strain
Filter the extract through a fine muslin cloth or paper filter.
This is your concentrated murasaki dye extract.
Dyeing Process
Dilute the extract with distilled water to make a dye bath.
DO NOT HEAT. Murasaki loses its purple hues and turns brown with heat.
Adjust pH for color shifts:
pH 6–7: bluish-purples
pH 8–9: brighter purples
pH 10+: risk of dulling or brown tones
Use pre-mordanted silk or wool for best uptake. Alum is preferred.
Soak your fabric or yarn in the cool bath for several hours (or overnight).
Rinse gently with cool water and air dry in the shade.
Notes:
Color may deepen with multiple dips.
Lightfastness is moderate, best for special projects, not everyday exposure.
You can freeze leftover extract to preserve it longer.
You can stop the dye process when the fabric has soaked up all the dye. The alkalinity and the mordant type and ratio will influence the final shade of your fabric.
Fun fact: During the Heian Period, sumptuary laws restricted murasaki-dyed clothing to the Empress and her ladies in waiting.
In soap, Purple Gromwell will provide a wide variety of shades ranging from purple to maroon depending on your soap’s PH, base oils and whether your soap gels or not. Soap made with Gromwell roots is called Shikon soap and is very famous in Japan .
More to read;
Dominique Cardon - Natural Dyes, pages 68-70
