Home Dyeing With Natural Dyes #250394

The fastness or permanence Of a dye IS important, but no dye is absolutely fast under all conditions. It may be fast to light, or to perspiration, or to washing, but not fast to all three. Furthermore, a dye may be fast on one fiber and not on another; or it may be fast when dyed by one method and not fast when dyed by another. Of all the textile fibers, wool can be dyed most easily, and the resulting colors change the least. It combines with practically all dyes, probably forming a chemical union with them. Cotton does not combine with dyes so well, and fast colors are produced on it only by complicated processes. The need for a particular kind Of fastness depends on the nature of the color change and the use to be made Of the dyed fabric. For example, a fabric dyed brown with tree bark may darken on exposure to light. If used in a hooked rug this color change might be satis factory but on the other hand, in window draperies it would soon become Objectionable. TO make sure that the recipes given on pages 8 to 35 produce colors permanent enough to be useful for most purposes, the dyed fabrics were tested for their fastness _to light and to washing by the following methods. The results are included in the dye recipes. For the light test, samples Of the dyed fabrics were cut and exposed for 40 hours to the rays Of a carbon arc lamp. Throughout the test period half Of each piece was shielded from the light while the rays Of the lamp shone directly on the other half.' Then the two parts were compared and the fastness to light rated as follows: Good — no appreciable change Of color; fair — appreciable but not Objectionable change Of color; poor — Objectionable change Of color. Though these light tests were run in a standard fading apparatus, the same method can be followed at home by exposing samples to the sunlight. Cut 2 — inch square openings in each Of two pieces Of heavy cardboard, fasten a piece Of the dyed cloth to one with gummed paper and cover with the other piece Of cardboard so that the openings correspond. It is important that the light come through the fabric. Then place this1 sample in its frame out Of doors in the direct sunlight and tilted towards the sun. After a few days remove and compare the section exposed to the sun with the covered portion.