The main species of plant dyes

Plant dyes are among the most widely used natural dyes, derived from various plant sources. These dyes have been an essential part of textile coloring for centuries and continue to be valued for their eco-friendly properties. Many plants contain pigments that can be extracted and processed into natural dyes, which are then used to color fabrics, paper, and other materials. Such plants are commonly referred to as "dye plants." Here are some of the most significant ones:

1. Sappan Wood (Suan Mu)
Sappan wood is a red vegetable dye known for its rich color and versatility. The active compound, hematoxylin, contains multiple hydroxyl groups, making it water-soluble and capable of producing different shades of red depending on the pH level. When combined with various mordants, it can create a range of colors, including dark red, purple, and reddish tones. Historically, it has been used in traditional dyeing practices and is sometimes called "Suga color." It works well on wool and cotton, and when treated with chromium oxide, it can produce a deep black color, known as "hematoxylin."

2. Buckwheat (Scorpion)
This yellow vegetable dye comes from the dried ripe fruits of the wolfberry plant. It is often used directly on silk fabrics, where it produces vibrant yellow hues. The concentration of the dye significantly affects the final result, and it offers good light fastness. When using suitable mordants, post-mordant dyeing methods help maintain color stability, with minimal fading over time. Its light fastness is generally around 3-4, which is quite good for natural dyes.

3. Indigo
Indigo is a classic blue plant dye, traditionally obtained from the leaves of the indigo plant. The pigment, known as indican, is converted into colorless indole phenols through fermentation and then oxidizes in the air to form the characteristic blue dye. This method has been used for generations, especially by ethnic minorities such as the Miao, Yao, Yi, and Buyi, who still use indigo in tie-dye and batik techniques today.

4. Purple Grass (Lithospermum)
Also known as "blood root" or "red stone root," purple grass is a natural source of purple dye. The pigment is mainly found in the roots and consists of naphthoquinone derivatives like shikonin and acetylshikonin. It has been used historically for dyeing textiles and is valued for its deep, rich color and stability.

5. Chestnut Husk
Chestnut husks are one of the oldest recorded natural dyes, known for their brown color. They are commonly used in traditional dyeing processes, with the shells, bark, and leaves all being suitable for dye extraction. These parts contain high levels of tannins, which contribute to the dye's effectiveness and durability on fabrics.