A dye is a colored substance that chemically bonds to the substrate to which it is being applied. This distinguishes dyes from pigments which do not chemically bind to the material they color. Dye is generally applied in an aqueous solution and may require a mordant to improve the fastness of the dye on the fiber.
A pigment is a powder used to add color or change visual appearance. Pigments are completely or nearly insoluble and chemically unreactive in water or another medium; in contrast, dyes are colored substances which are soluble or go into solution at some stage in their use. Dyes are often organic compounds whereas pigments are often inorganic. Pigments of prehistoric and historic value include ochre, charcoal, and lapis lazuli.
In chemistry, chromism is a process that induces a change, often reversible, in the colors of compounds. In most cases, chromism is based on a change in the electron states of molecules, especially the π- or d-electron state, so this phenomenon is induced by various external stimuli which can alter the electron density of substances. It is known that there are many natural compounds that have chromism, and many artificial compounds with specific chromism have been synthesized to date. It is usually synonymous with chromotropism, the (reversible) change in color of a substance due to the physical and chemical properties of its ambient surrounding medium, such as temperature and pressure, light, solvent, and presence of ions and electrons.
Quinacridone is an organic compound used as a pigment. Numerous derivatives constitute the quinacridone pigment family, which finds extensive use in industrial colorant applications such as robust outdoor paints, inkjet printer ink, tattoo inks, artists' watercolor paints, and color laser printer toner. As pigments, the quinacridones are insoluble. The development of this family of pigments supplanted the alizarin dyes.
Lithol Rubine BK is a reddish synthetic azo dye. It has the appearance of a red powder and is magenta when printed. It is slightly soluble in hot water, insoluble in cold water, and insoluble in ethanol. When dissolved in dimethylformamide, its absorption maximum lies at about 442 nm. It is usually supplied as a calcium salt. It is prepared by azo coupling with 3-hydroxy-2-naphthoic acid. It is used to dye plastics, paints, printing inks, and for textile printing. It is normally used as a standard magenta in the three and four color printing processes.
Arylide yellow, also known as Hansa yellow and monoazo yellow, is a family of organic compounds used as pigments. They are primarily used as industrial colorants including plastics, building paints and inks. They are also used in artistic oil paints, acrylics and watercolors. These pigments are usually semi-transparent and range from orange-yellow to yellow-greens. Related organic pigments are the diarylide pigments. Overall, these pigments have partially displaced the toxic cadmium yellow in the marketplace. Painters such as Alexander Calder and Jackson Pollock are known to have employed arylide yellow in their artworks.
3,3'-Dichlorobenzidine is an organic compound with the formula (C6H3Cl(NH2))2. The pure compound is pale yellow, but commercial samples are often colored. It is barely soluble in water and is often supplied as a wet paste. It is widely used in the production of diarylide yellow pigments used in the production of printing inks. Its use in the production of dyes has been largely discontinued because of concerns about carcinogenicity.
Pigment Yellow 16 is an organic compound that is classified as a diarylide pigment.
Acetoacetanilide is an organic compound with the formula CH3C(O)CH2C(O)NHC6H5. It is the acetoacetamide derivative of aniline. It is a white solid that is poorly soluble in water. This chemical and many related compounds (prepared from various aniline derivatives) are used in the production of organic pigments called arylide yellows, one example being Pigment Yellow 74.
Pigment Yellow 83 is an organic compound that is classified as a diarylide pigment. It is used as a yellow colorant.
Violanthrone, also known as dibenzanthrone, is an organic compound that serves as a vat dye and a precursor to other vat dyes. X-ray crystallography confirms that the molecule is planar with C2v symmetry. Isomeric with violanthrone is isoviolanthrone, which has a centrosymmetric structure.
Pigment Yellow 10 is an organic compound that is classified as a monoazopyrazolone pigment. It is used as a yellow colorant, notably as yellow road marking on highways in the US.
The conservation and restoration of woodblock prints, is the process of caring for and repairing images made from a specific printing process involving using wooden reliefs to stamp or imprint an image onto paper. The process of creating woodblock prints as Asian examples are known, or woodcuts as Western examples are called, has been known for many centuries, and many older prints have experienced aging and deterioration of the paper and colorants used.
Pigment Yellow 12 is an organic compound and an azo compound. It is a widely used yellow pigment. It is also classified as a diarylide pigment, being derived from 3,3'-dichlorobenzidine. It is closely related to Pigment Yellow 13, wherein the two phenyl groups are replaced by 2,4-xylyl. According to X-ray crystallography, the molecule is nearly planar and exists as the keto-hydrazide tautomer.
Pigment Yellow 13 is an organic compound and an azo compound. It is a widely used yellow pigment. It is also classified as a diarylide pigment, being derived from 3,3'-dichlorobenzidine. It is closely related to Pigment Yellow 12, wherein the two xylyl groups are replaced by phenyl and to Pigment Yellow 14 where the xylyl groups are replaced by o-tolyl. It is often depicted as an azo (-N=N-) structure, but according to X-ray crystallography closely related compounds exist as the keto-hydrazide tautomers.
A colorant is any substance that changes the spectral transmittance or reflectance of a material. Synthetic colorants are those created in a laboratory or industrial setting. The production and improvement of colorants was a driver of the early synthetic chemical industry, in fact many of today's largest chemical producers started as dye-works in the late 19th or early 20th centuries, including Bayer AG(1863). Synthetics are extremely attractive for industrial and aesthetic purposes as they have they often achieve higher intensity and color fastness than comparable natural pigments and dyes used since ancient times. Market viable large scale production of dyes occurred nearly simultaneously in the early major producing countries Britain (1857), France (1858), Germany (1858), and Switzerland (1859), and expansion of associated chemical industries followed. The mid-nineteenth century through WWII saw an incredible expansion of the variety and scale of manufacture of synthetic colorants. Synthetic colorants quickly became ubiquitous in everyday life, from clothing to food. This stems from the invention of industrial research and development laboratories in the 1870s, and the new awareness of empirical chemical formulas as targets for synthesis by academic chemists. The dye industry became one of the first instances where directed scientific research lead to new products, and the first where this occurred regularly.
Pigment Orange 13 is an organic compound and an azo compound. It is a commercial orange pigment. It is also classified as a diarylide pigment, being derived from 3,3'-dichlorobenzidine. It is closely related to Pigment Orange 34, wherein the two phenyl groups are replaced by p-tolyl groups. Its structure has been confirmed by X-ray crystallography.
Pigment Yellow 74 is an azo dye and classified as an arylide yellow. It is an intensely yellow-green solid. It is prepared by azo coupling of the diazonium derivative of 2-methoxy-4-nitroaniline with 2-methoxyacetoacetanilide. It is a flat molecule, enforced by the hydrogen-bonding via the ketohydrazide group.
Pigment Yellow 97 is widely used as a yellow colorant, and is classified as an arylide yellow. It is distinguished by the presence of a sulfonylaminophenyl group, which renders the material particularly insoluble. It is derived from two fairly complicated precursors. The acetoacetanilide component is made from 2,5-dimethoxy-4-chloroaniline. The azo component is made from a dimethoxyaniline with the sulfonylaminophenyl substituent.he compound is obtained via acetoacetylation of o-tolidine using diketene. The resulting bisacetoacetylated compound is coupled with two equiv of the diazonium salt obtained from 2,4-dichloroaniline. Although it is often depicted as an azo compound, X-ray crystallography shows that the molecule exists as a hydrazone.
Pigment Yellow 14 is an organic compound classified as an azo compound. It is a commercial yellow pigment. It is also classified as a diarylide pigment, being derived from 3,3'-dichlorobenzidine. It is closely related to Pigment Yellow 13, wherein the two xylyl groups are replaced by an ortho tolyl. It is often depicted as an azo (-N=N-) structure, but according to X-ray crystallography closely related compounds exist as the keto-hydrazide tautomers.
Pigment Yellow 17
Pigment Yellow 14
Pigment Yellow 63
