Dyes are colored, aromatic, or ionizing substances that exhibit affinities toward the substrates to which users apply them. Most dyes rely on aqueous solutions for application. The use of dyes is abundant in textiles and fabrics. Dye in liquid form can change the color of textiles, paper, plastics, leathers, and other materials.  Read More

Types of Dyes
Today, consumers can purchase natural and synthetic dyes for a variety of uses. There are different groups of dyes with special properties depending on the application. Acid dyes, for example, are best for altering the color of leather, paper, silk, wool, and synthetic materials. Cationic dyes are considered basic dyes and mostly used to dye acrylics. In addition, there are sulfur dyes, reactive dyes, vat dyes, and many other types.

Cellulosic fibers can undergo the simplest dying processes, including vat dyes, fiber-reactive dyes, and direct dyes. Protein fibers like materials from animals (wool and leather) require acid dyes for lasting results. While most modern consumers purchase their textiles pre-dyed, it is possible to dye materials at home. Only certain projects are suitable for home dying, such as direct dyes and fiber-reactive dyes.

“Direct dyeing” refers to affordable, easily applied dyes that yield bright colors. Conventional dyes, or synthetic, chemical-based dyes, should not be used in DIY projects. These dyes are reserved for industrial applications and mass dyeing of textiles. Natural dyes are created using clays, herbs, teas, and other organic matter. Low-impact dyes create the same colors as conventional dyes without the use of certain chemicals. These dyes are more environmentally conscious than conventional dyes.

Dyes vs. Pigments
Dyes and pigments show color in the same way by absorbing wavelengths of light, but they are completely different substances. Dyes cling to the substrate of where they are applied. People use dyes in textiles, food, and hair for artistic and creative purposes, as well as for identifiers. Pigments are the elements in paints, plastics, fabrics, food, and inks. They are insoluble materials that require mixing with other substances before attachment to a substrate. Pigments retain their color longer than dyes and withstand UV rays, heat, weathering, and exposure to chemicals.

The fields of synthetic chemistry, materials science, and chemical engineering may all handle dyes and pigments at some juncture. Museums may study dyes to date historical artifacts and find out the original location of the artifact. Forensic scientists can analyze dyes and pigments at crime scenes to put together a case and determine details. Chemists may work with dyes and pigments to develop new, longer-lasting formulas or dyes that use less expensive ingredients. Dyes using natural, sustainable, and environmentally friendly materials are currently under development.

Functional Dyes
Dyes have a number of uses beyond making textiles aesthetically appealing. Functional dyes have high-tech applications and are involved in solar cells, the treatment of cancer, and fluorescent sensors. Functional dyes are important in emissive displays, electronic materials, imaging technologies, laser and thermal printing, optical data storage, and in the biotechnology field. Photodynamic therapy in anticancer treatment uses dyes and a specific type of light to produce a type of oxygen that destroys cancer cells.

Summary
Dyes can be natural or synthetic substances that act as colorants. The color of dyes can be seen by the naked eye because dyes absorb light in the color spectrum. Materials like paper, leather, and silk are dyed using acid dyes. Certain types of dyes such as conventional dyes should not be used for DIY products. Natural dyes are a better option to use for DIY projects. Pigments are integrated more into their substrates than dyes. For this reason, pigmented colors last longer than most dyes. Along with dyes used for coloration, there are purposive dyes that are used in hospitals, solar panels, and in cancer treatments.  Read Less