1.
Dye identification<br />Objective: Identification of dye stuff<br />Preparation of Test Specimen<br /><ul><li>A tuft of fibre or yarn of about 3 cm in length or for fabric 3 x 3 centimeter specimen used.

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The Test Specimen is successively teated with a)50% dimethylformamide

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b)conc dimethlformamide and c) a mixture of glacial acetic acid and rectified spirit (1:1,v/v) at boil for 3 to 4 minutes with intermediate washing and squeezing</li></ul>All sulphur, oxidation black and vat dyes decolourizes or change shade radically. The color of the test specimen is restored on exposure to air or with vat dye developer.<br />Take a fresh test specimen; boil it with sodium sulphoxylate formaldehyde-glycol solution containing few drops of sodium hydroxide solution (44%). Test specimen is decolorized or altered in shade.The solution is yellow, bluish red, etc. original color restored by vat-dye developer<br />Take test specimen. Treat it with ethylenediamine & glucose. Colour is more or less removed at boiling point.<br />Result: Conformed vat dye<br />Colour fastness to rubbing<br />Objective: The test is designed to determine the degree of colour that may transfer from the surface of coloured textile to other surface.<br />A coloured specimen fastned to the base of a crocmeter is rubbed with a white crock test cloth under controlled conditions. Colour transferred is compared with chromatic transfer scale or gray scale.<br />Result: Rating 5<br />Colour fastness to washing<br />Objective: To test colour fastness to washing<br />The test specimens are laundered under appropriate conditions of tempture, bleaching & abrasive action. The colour change of the test specimen & the staining of the multifiber fabric are visually evaluated.<br />The instrument used is called LaunderOmeter. <br />The size of the test sample is 2” x 4”. A muliti fibre fabric is attached to the sample.<br />Result: Rating 5<br />