Glossary

Acid Dye- Applied to polyamide fibres from acidic solutions. Essentially synthetic dyes, they are used for silk, wool and nylon.

Affinity- In dyeing, affinity means the preferential attraction of dye towards fibre rather than for solution of the dye bath. A dye that has strong affinity easily leaves the dye solution of dispersion and attaches itself to the fibre being dyed.

Aniline- Aniline is a very commonly used term in the synthesis of dyes. Chemical formula - C6H7N. Also known as aniline oil and used as a sort of synonym for synthetic dyes.

Azo- Azo refers to a chemical compound that contains double nitrogen atoms with a double bond between them (-N=N-). Azo dyes forms the largest group of dyes and display light-fastness, stability, strongness and respond well to mixing. Azo dyes may be found among the dye classes of direct, acid, basic, reactive and disperse.

Basic Dye- Basic dyes are generally cationic dyes. Basic dyes are the dyes that is able to react with acidic groups on fibres.

Bifunctional Reactive Dye- These dyes are designed for having the potential to react with the fibre in more than a single way.

Binder- A colorless material used to attach a pigment to fabric. Binders are like "glue" that holds the pigment in place. Example: Paints that has pigments mixed with binders.

Cation- Known as the positively charged ion. Numerous chemicals applied in textile processing are referred to as cationic.

Cellulose- A polymer consisting of a large numbers of units, each of the general formula represented by C6H10O5.

Chromophore- A color-bearing compound that has a special property found in an organic molecule which make it appear colored.

Colour Index- A publication jointly brought out by the Society of Dyers and Colorists of Great Britain and the American Association of Textile Chemists and Colorists.

Chrome- Any salt of chromium, that is used in tanning and dyeing.

Direct application- A method usually used to describe a process where a solution of dye is locally applied to different areas of fabric, like squirting, painting, spraying, stamping, etc.

Direct Dye- A dye that is carried out by immersing the fibre in a dye solution without any requirement of other chemicals for bonding the dye to the fibres.

Disperse Dye- Disperse dyes are found in the dye bath as a kind of suspension or dispersion of microscopic particles, with only a minuscule amount in true solution at any given moment of time.

Enzyme- Enzymes are now popularly used in textile processing. These are the type of protein that perform the role of a catalyst in a biochemical reaction. Examples: Amylase - applied for desizing; Cellulase - Used in modification of cellulosic fabrics.

Exhaust Dyeing- Exhaust Dyeing is used for denoting the application of a dye bath of a moderately larger liquor to goods ratio, where the fibre is immersed for a while. It allows the dye molecules to exit the bath and get attach to the fibres.

FBA- Fluorescent brightening agent.

Fixation- Fixation refers to the formation of a sort of final bond between the fibre and dye. The bond type formed changes with the type of dye and the fibre.

Gel Dyeing- A continuous type of tow-dyeing method where soluble dyes are used to wet-spun fibres in the gel state (i.e. After the processes of extrusion and coagulation, but before drying and drawing).

Illuminating Dye- A dye that is mixed with discharge paste in printing methods also referred to as head dyes.

Indigo- A sort of natural or synthetic vat dye given the designation of Color Index Vat Blue 1. Indigo is perhaps one of the oldest colorants that is used for textiles. Originally extraction was done from plants, but now it is usually synthetic.

Lake- The pigments that are produced as a result of absorption of the dye on the substrate. Most common substrate can be alumina hydrate.

Liquor ratio (also liquor to goods ratio)- The ratio that is used to denote the weight of the dyebath or any other processing bath to the weight of goods that is being dyed or processed.

Lightfastness- Light Fastness is typically used as measurement to ascertain how resistant a coloring material, such as dye would be fading when exposed to light.

Metal- Complex Dye- A dye that typically has co-ordinated metal atoms in its molecule.

Mordant- Chemicals that helps in attachment of dyestuff to fibres by bonding to the fibre as well as to the dye.

Non-ionic - A chemical that does not ionize in a solution while remaining is in intact molecular form some surfactants are non-ionic.

No-wick HF- Used with Liquid Decorator Colors, for enabling fine line drawing.

pH- A perfect measure of the concentration of hydronium that is found in a solution.

Pigment- A substance used in the particulate form that is substantially insoluble in a medium.

Reactive Dye- A dye that, under proper conditions, can react chemically with a substrate for forming a covalent dye-substrate linkage.

Retayne- A type of cationic dye fixing agent. Typically used on cotton fabrics for improving wet fastness of the direct dyes and to add color paper pulp.

Sodium Hydroxide- It is a strong base; also called caustic soda or lye, or just "caustic" in dyeing terms. Chemical Formula: NaOH.

Sulphur Dye- A dye, that contains sulphur as an integral part of the chromophore and as well as in attached polysulphide chains. Sulphur dyes are not soluble in water, and must get converted to a soluble form before application.

Sublimation- It is the conversion of solid directly into gas, without passing through the liquid phase.

Tannic Acid- A mixture of compounds derived from natural sources like oak. Tannic acid treatment, followed by a treatment of tartar emetic, has been reported to improve the wash fastness of dyed nylon or wool.

Ultraviolet- The light that is beyond the portion that is visible of the light spectrum at the blue end. It is the Ultraviolet light that causes fading of colors, and makes fluorescent compounds glow.

Union Dye- A dye that is generally a mixture of two or more different classes of dye. It is used to dye blends of fibres.

Vat Dye- Vat dyes are water-insoluble dye containing keto groups, which is normally applied to the fibre from an aqueous alkaline solution of the reduced enol (leuco) form, that subsequently gets oxidised in the fibre to an insoluble form.

Vinyl Sulphone- Vinyl sulphone reactive dyes are generally intermediate in their reactivity, so they are used above room temperature, but considerably below the boiling point of water. These are typically used for cellulosic fibres and with some use for wool also.

Washfastness- Washfastness is used to measure resistance of a dye to washing out.

Wetting Agent- A chemical that helps the water to penetrate a material or to form a film over its surface; usually it is a surfactant. Wetting agents are generally used in the dyeing process where it helps the dye solution to penetrate to the individual fibres.

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