Sukumo

Definition and Overview

Sukumo is a dye material made by fermenting, drying, and aging indigo leaves. It is not used as-is by dissolving in water; instead, it is used by making an indigo dye bath using alkali such as wood ash lye and a reduced state, turning it into a dye liquor suitable for dyeing.

Sukumo is not a term for the type of fabric or weave structure. Also, indigo dyeing is a broad term for the process of making and maintaining a dye bath, and dyeing with indigo-related dyes; sukumo is one of its raw materials.

Color and Texture Characteristics

In sukumo indigo dyeing, color appears when the material is exposed to air immediately after being lifted from the dye bath. The depth of color is adjusted from light blue to deep navy by the number of times dipping and oxidation are repeated and by the condition of the dye bath.

There may be differences in color due to the raw material, dyeing conditions, type of fiber, lot, and other factors. It is used not only when a uniform color is emphasized, but also when slight variations in shade and changes over time are used as a design element.

Sukumo itself is not a processing method that adds functions such as absorbency or warmth retention to fabric. The wearing feel and appearance vary greatly depending on the material being dyed, yarn use, woven or knitted structure, and finishing process.

Main Uses

Yarn and fabric dyed with sukumo are used for shirts, dresses, haori jackets, pants, accessories, and more. Depending on the material being dyed, such as cotton, linen, or silk, and the product design, they are developed for a wide range of uses from year-round items to spring and summer items and autumn and winter items.

In yarn dyed before weaving and fabric dyed after weaving or knitting, the appearance and the planning and production process differ. Based on the intended color tone, whether a pattern is needed, and the required quantity, it is important to confirm the dyeing process early.

• For apparel, natural materials are mainly used.
• It is also used for scarves, bags, and fashion accessories.
• For dark-colored products, check for color transfer to white or light-colored trims and linings.

Selection and Handling Precautions

During planning, in addition to color samples, conduct test dyeing on the actual fabric to be used, and check the color in wet and dry states, lot-to-lot color differences, rubbing fastness, and wash fastness. In particular, products intended to be worn with light colors or layered should be evaluated for color transfer.

For washing, follow the product's care label, and in the beginning it may be necessary to take precautions such as washing separately. Long soaking, strong friction, use of bleach, and long drying in direct sunlight may lead to changes in the shade or transfer to other items.

Before sewing, check the fabric shrinkage rate and, if necessary, prewash it. Dark indigo-dyed fabric may stain through rubbing during sewing, so keep the area around the sewing machine and the pressing cloth clean, and be careful about color transfer to white auxiliary materials.

Differences from Similar Terms

Indigo dyeing is a general term for dyeing that uses indigo. Because it may also use synthetic indigo, it is not synonymous with indigo dyeing using sukumo as the raw material. On product and fabric labels, check the type of dye and the dyeing method separately.

Natural dyeing broadly refers to dyeing that uses plant-derived dyes. Sukumo is made from indigo, so it is sometimes treated as a type of natural dyeing, but its distinctive feature is that the dye bath is kept in a reduced state for dyeing.

Frequently Asked Questions