absorbing dyestuflFs should be removed by washing. Spots and stains cause 

 uneven dyeing and should also be removed before washing. 



4. Washing Wool 



Before dyeing wool, use the following washing procedure. Dissolve 

 neutral soap in 5 gallons of lukewarm (95° F.), soft water. Wash the ma- 

 terial thoroughly and squeeze out suds. Repeat the washing procedure. 

 After the second washing squeeze out the suds, rinse the material three 

 or four times, or until all traces of soap have been rinsed away. 



Felting and shrinkage can be avoided if wool is handled quickly and 

 gently throughout the washing and dyeing processes. Always squeeze 

 excess moisture out of materials. Never wring or twist wool. Also, since 

 sudden temperature changes will cause wool to shrink and become harsh, 

 the following measures should be taken to avoid these conditions. First, 

 keep the temperature of the material as even as possible by transferring 

 it directly from suds to rinses without delay; second, keep the water at a 

 lukewarm temperature for all suds and rinses. 



If unspun wool is to be used for dyeing, the raw wool must be thoroughly 

 scoured and cleaned first. The natural wax and grease in raw wool tend 

 to make the fiber water repellent, thus the dye solution cannot penetrate. 

 After scouring (Davenport, 1964, p. 117) and dyeing, wool is cai*ded and 

 spun into yarn. When wool from different dye lots is blended together in 

 carding, interesting tweed color effects can be achieved. 



5. Washing Cotton 



Before dyeing cotton, use the following washing procedure. Dissolve 

 neutral soap in 5 gallons of hot (140° F.), soft water. Wash the material 

 thoroughly and squeeze out suds. Repeat the washing procedure, then 

 rinse. The second rinse water should be hotter than the first one, and the 

 material should be allowed to soak in it for at least a half hour. This should 

 be followed by two or three cooler rinses. 



Mordants 



Many natural dyes will fade and "bleed" badly unless the yarn or fabric 

 is first treated with a chemical called a mordant, a metallic salt that helps 

 to fix the color to the fiber. The mordants commonly used with the natural 

 dyestuffs are alum (aluminum potassium sulfate), chrome (potassium 

 dichromate), copperas (ferrous sulfate), and tannic acid or some other 

 source of tannin such as oak galls or sumach leaves. Commercial dyers use 

 oils and other substances too difficult for the home dyer to apply. 



By using different mordants, a variety of shades and sometimes even 

 different colors may be obtained from a single dyestuff. For example, on 

 wool, dahlia flowers used with a chrome mordant give an orange color 



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