Dye can bring a little color to life. Most clothing is colored with dyes. Modern, manufactured dye can be costly. Natural dyes from plant and animal products have been used since ancient times. So this week we describe a natural way to dye wool.

The advise comes from information written by Jenny Dean of the intermediate technology development group in Britain. This anti-poverty group is now called practical action.

There are several methods to put dye onto material. The wet/vat method, for example, can be used to dye wool with onionskins. For this example, use 100 grams of natural wool. The wool must be clean. Leave it over night in water and liquid soap. Than wash it with the clean water that is a little warm. Gently squeeze out the extra water.

A solution called a mordant is used in dying process. A mordant helps fix dye to the material. Traditionally, mordant were found in nature. Wood ash is one example. But chemical mordants such as alum are popular today. Alum is sold in manystores. It is often makes/mixed with cream of tartar, a fine powder commonly used in cooking.

/ daI; daI/ n [C, U] substance used for dyeing 染料

vat

 / vAt; vAt/ n tank or large container for holding liquids, esp in distilling, brewing, dyeing and tanning 大桶、大盆等巨大容器（尤指蒸馏、酿造、染色及鞣革用的）.

onionskin

n [U] AmE very thin light paper, used in the past especially for writing letters

mordant['mor·dant || 'mɔrdənt /'mɔːd-]

(名) 金属腐蚀剂, 金箔粘着剂

alum

 / 5AlEm; `AlEm/ n [U] white mineral salt used in medicine and in dyeing 明矾, 白矾（用于医药及染色）.

tartar[tar·tar || 'tɑrtə(r) / 'tɑː-]

(名) 酒石; 凶悍的人; 牙石, 牙垢

powder

 / 5paUdE(r); `paJdL/ n
(a) [U] (substance in the form of a) mass of fine dry particles 粉; 粉末; 粉状物质: