Hubbry Logo
ColourantColourantMain
Open search
Colourant
Community hub
Colourant
logo
7 pages, 0 posts
0 subscribers
Be the first to start a discussion here.
Be the first to start a discussion here.
Colourant
Colourant
Colourant
View on Wikipedia
from Wikipedia

A colourant/colour additive (British spelling) or colorant/color additive (American spelling) is a substance that is added or applied in order to change the colour of a material or surface. Colourants can be used for many purposes including printing, painting, and for colouring many types of materials such as foods and plastics. Colourants work by absorbing varying amounts of light at different wavelengths (or frequencies) of its spectrum, transmitting (if translucent) or reflecting the remaining light in straight lines or scattered.

Most colourants can be classified as dyes or pigments, or containing some combination of these. Typical dyes are formulated as solutions, while pigments are made up of solid particles suspended and are generally suspended in a vehicle (e.g., linseed oil). The colour a colourant imparts to a substance is mediated by other ingredients it is mixed with such as binders and fillers are added, for example in paints and inks. In addition, some colourants impart colour through reactions with other substances.

Colourants, or their constituent compounds, may be classified chemically as inorganic (often from a mineral source) and organic (often from a biological source).

Regulation

[edit]

United States

[edit]

In the US, the Food and Drug Administration (FDA) regulates colourants for food safety and accurate labelling.[1]

See also

[edit]

References

[edit]
Revisions and contributorsEdit on WikipediaRead on Wikipedia

Colourant

View on Grokipedia
from Grokipedia
A colourant is a substance used to impart color to materials such as textiles, paints, plastics, ceramics, and food products, enabling both aesthetic and functional applications across industries. These compounds absorb light in the visible spectrum (400–700 nm) due to electronic transitions within their molecular structure, producing the perceived hue. Colourants are broadly classified into two main types: dyes and pigments. Dyes are soluble organic compounds, typically applied from aqueous solutions to substrates like fibers, where they form strong bonds to achieve permanent coloration. In contrast, pigments are insoluble, finely divided particles dispersed in a medium such as or , providing opacity and color intensity through and absorption. The color in both arises from chromophores—specific molecular groups with conjugated systems of double bonds that facilitate delocalization and visible absorption—often enhanced by auxochromes like groups (-SO₃H) that improve and color intensity. The development of colourants dates back to ancient natural sources but advanced significantly with the synthesis of the first artificial dye, , by William Perkin in 1856, sparking the modern . Today, major classes include azo dyes (comprising about 66% of production), anthraquinones (15%), and phthalocyanines (2%), selected based on substrate affinity, fastness to light and washing, and environmental considerations. Beyond traditional uses in textiles and coatings, colourants play critical roles in high-technology fields, such as displays, technologies, and in medicine.

Definition and Classification

Definition

A colourant is any substance that imparts color to other materials by selectively absorbing certain wavelengths of while transmitting or reflecting the remaining wavelengths, thereby altering the perceived color of the illuminated object. This selective absorption occurs primarily in the , which spans wavelengths from approximately 400 to 700 nanometers, where the energy excites electrons in the colourant's molecular structure from a to an . Colourants encompass a broad range of compounds, with pigments and dyes serving as key subsets; pigments are typically insoluble particles that provide color through dispersion, while dyes are soluble and bond directly to substrates. The fundamental function of colourants relies on these optical properties: absorption removes specific light wavelengths, reflection bounces them back to the observer, and transmission allows them to pass through translucent materials, all contributing to the final hue observed by the human eye. This principle distinguishes colourants from mere color perception, as the substances actively modify light interaction rather than passively exhibiting inherent traits. In everyday applications, colourants are integral to coloring fabrics, foods, paints, and , enhancing aesthetic appeal and functionality across industries. For instance, ancient humans utilized natural colourants like —a iron-rich clay —for body adornment and artistic expression, as evidenced by red ochre residues in 100,000-year-old artifacts from in , marking some of the earliest known uses in .

Classification

Colourants are primarily classified based on their origin into natural and synthetic categories. Natural colourants are derived from plant, animal, or mineral sources, offering biodegradable and generally nontoxic options, such as extracted from tomatoes or carrots. In contrast, synthetic colourants are produced through in laboratories, providing greater stability and cost-effectiveness, though they may pose concerns in certain applications. A representative example of a natural animal-derived colourant is , a bright-red pigment obtained from the dried bodies of insects. Another key classification distinguishes colourants by their physical form and application method: dyes and pigments. Dyes are soluble organic compounds that dissolve in the application medium, such as or solvents, and bond at the molecular level to substrates like fibers or plastics, yielding brilliant, transparent colors. Pigments, however, are insoluble particles that remain dispersed in a vehicle or binder without dissolving, providing opaque, durable coloration through physical or reflection of . For instance, FD&C Blue No. 1 () exemplifies a synthetic dye, a water-soluble compound used in foods, , and pharmaceuticals for its intense hue. Colourants can also be categorized by their chemical nature into inorganic and organic classes. Inorganic colourants typically consist of metal compounds or oxides, such as , which offer excellent weather resistance and opacity but generally lower color intensity. Organic colourants, derived from carbon-based structures, provide brighter shades and higher tinting strength, though they may have reduced stability beyond 200°C. serves as a prominent inorganic , produced by incomplete of hydrocarbons to yield a fine, black particulate material with high hiding power and . Hybrid colourants, such as lakes, bridge the gap between dyes and pigments by precipitating water-soluble dyes onto insoluble substrates like aluminum or calcium salts, resulting in lipid-soluble, pigment-like particles that enable use in oil-based or non-aqueous systems. This process enhances the insolubility and versatility of the original , as seen in FD&C No. 1 Lake, which combines the synthetic with an aluminum substrate for applications requiring dispersion rather than dissolution. Lakes are particularly valuable in industries like and , where they provide stable, vivid colors without the solubility limitations of straight dyes.

History

Ancient and Traditional Use

The use of colourants dates back to the era, where early humans employed natural pigments such as and for body decoration and art. Evidence from archaeological sites indicates that , an iron oxide-rich , was used as early as 100,000 years ago for symbolic purposes, including skin coloring, while served as a black in artistic expressions. By approximately 36,000–30,000 years ago, these materials appeared in European paintings, such as those in , , marking some of the earliest known applications of colourants in visual storytelling and possibly ritualistic contexts. In ancient civilizations, colourants played integral roles in cultural practices, particularly in and . utilized plant-based dyes like and madder (derived from roots) for mummification processes and coloring as early as 2000 BCE, often mixing madder with to achieve hues on wrappings and portraits. Similarly, the Maya and Aztec peoples in extracted vivid red dyes from insects (Dactylopius coccus), farmed on prickly pear cacti, applying the pigment in rituals symbolizing blood, the sun, and deities, as well as for dyeing fabrics and manuscripts traded across Central and South America. Traditional sources further diversified these practices; plant extracts from (Lawsonia inermis) provided reddish-brown tones for body adornment and textiles in ancient , while mineral pigments like , sourced from , yielded deep blues for elite artworks and adornments. Colourants held profound cultural significance, influencing rituals, social status, and economic networks. In around 1500 BCE, —a luxurious dye extracted from sea snails—became a symbol of royalty and divinity, requiring thousands of snails per garment and driving maritime trade. Along ancient trade routes like the , (from stigmas) was exchanged from regions such as Persia and starting in the 1st millennium BCE, valued for its yellow hue in ceremonial textiles and medicines across Eurasian cultures. Early dyeing techniques, including mordanting with metal salts like to fix colours onto fibers, enhanced durability and were practiced in civilizations from ancient to the Mediterranean, facilitating vibrant, long-lasting applications in rituals and daily life. Medieval alchemists in and the Islamic world built on these traditions through experimental attempts to synthesize dyes, manipulating substances to mimic or improve natural colors, laying groundwork for later chemical innovations.

Industrial and Modern Development

The discovery of , the first synthetic , by in 1856 marked a pivotal in colourant , accidentally occurring during his attempts to synthesize from and igniting the industry. This breakthrough shifted production from labor-intensive natural sources to scalable chemical synthesis, enabling vibrant, consistent colors for textiles and beyond. By the late , the industry expanded rapidly, with German firms such as , , and Hoechst achieving dominance; these companies controlled nearly 90% of the global synthetic market by the early through innovations in and from raw materials to finished products. The 20th century saw further innovations amid geopolitical disruptions, including the development of azo dyes following Johann Peter Griess's 1858 discovery of diazotization, which enabled a vast array of affordable, versatile colorants for industrial applications. dyes, accidentally discovered in 1907 as a in experiments and with key metal complexes developed in the late , were commercialized in the by firms like ICI and , providing stable blues and greens resistant to fading. severely disrupted supply chains by severing access to German dyes, prompting the to establish its own synthetic organic dye industry to meet demands. A similar but less transformative impact occurred during , as Allied blockades further diversified global production. Postwar, the focus shifted to high-performance pigments optimized for emerging materials like plastics, with organic variants designed for heat and chemical stability entering widespread use by the mid-20th century. In the , post-2000 advancements have emphasized and performance, including for enhanced dispersion and color uniformity in coatings and textiles, as seen in nanoparticle-based formulations that reduce aggregation and improve . Bio-based synthetic colorants, derived from renewable agro-industrial wastes via microbial or enzymatic processes, have gained traction as eco-friendly alternatives to petroleum-derived dyes, with examples like bio-indigo for production scaling commercially. Regulatory milestones, such as the U.S. Food and Drugs Act of 1906, laid early groundwork by prohibiting deleterious synthetic colors in foods, influencing global standards for safe colourant use. Economically, the global dyes and pigments market has grown from artisanal origins to a $40 billion industry in 2023, driven by demand in textiles, automotive, and sectors.

Chemical Properties

Color Mechanisms

Colourants produce visible color primarily through the selective absorption of in the (400–700 nm), where molecules absorb specific wavelengths and reflect or transmit others, leading to the perception of by the . For instance, in plants absorbs and blue light while reflecting , resulting in the observed green hue. This absorption occurs when electrons in the colorant molecule are excited from ground to higher energy states, with the energy difference corresponding to visible wavelengths. The key structural feature enabling this color production is the , a molecular group responsible for light absorption, typically consisting of conjugated systems of double bonds that delocalize electrons and extend absorption into the visible range. In organic colorants, these conjugated pi-electron systems lower the energy gap between molecular orbitals, allowing absorption of longer wavelengths. Inorganic colorants, by contrast, often derive color from d-d electron transitions in metal ions or charge transfer processes. The intensity of color in dye solutions is quantitatively described by the Beer-Lambert law, which relates to concentration: A=ϵlcA = \epsilon l c where AA is the , ϵ\epsilon is the molar absorptivity (a measure of the colorant's at absorbing at a specific ), ll is the path of the through the solution, and cc is the concentration of the colorant. This law is fundamental for characterizing dye strength and is widely applied in analysis of colorants. Certain colourants exhibit beyond simple absorption, including and , where absorbed energy is re-emitted as after a delay. colorants, such as , absorb and re-emit it in the blue region, enhancing perceived whiteness in textiles and papers. involves longer-lived emission from triplet states, as seen in glow-in-the-dark pigments that store and slowly release energy. The observed color of colourants can be influenced by environmental factors, including and interactions. sensitivity arises from or altering the chromophore's electronic structure, shifting absorption wavelengths; for example, many natural dyes change from in acidic conditions to in alkaline ones. , known as solvatochromism, occur due to differential stabilization of excited states by solvent polarity, causing bathochromic or hypsochromic shifts in color.

Chemical Structures and Classes

Colourants are broadly categorized into organic and inorganic classes based on their molecular composition, with each class exhibiting distinct structural features that determine their coloration and performance. Organic colourants primarily derive their hue from conjugated π-electron systems within aromatic frameworks. Azo dyes, the most prevalent organic class, feature a characteristic azo linkage (-N=N-) connecting two aromatic rings, represented generally as R-N=N-R', where R and R' are organic substituents. A representative example is (C14H14N3NaO3S, CAS 547-58-0), which contains a dimethylamino group on one phenyl ring and a group on the other, enabling its use as an acid-base indicator with orange-to-yellow color transitions. are based on the core (C14H8O2), a fused system with two carbonyl groups, often substituted with hydroxyl groups for enhanced solubility and color intensity; (1,2-dihydroxyanthraquinone, C14H8O4, CAS 72-48-0) exemplifies this structure, providing a vibrant hue historically extracted from madder root. dyes consist of a large macrocyclic ring coordinated with a central metal ion, such as copper in (C32H16CuN8, CAS 147-14-8), which imparts intense blue-green shades due to its extended conjugation and planarity. Inorganic colourants, in contrast, rely on ionic lattices or coordination compounds for color generation, often through d-d electron transitions in transition metals. Metal oxides form crystalline structures where color arises from metal-oxygen charge transfer or band gaps; red iron oxide (, α-Fe2O3, CAS 1309-37-1) adopts a corundum-type lattice with Fe3+ ions in octahedral coordination, yielding a stable red . Complex salts involve polynuclear coordination, as in (ferric ferrocyanide, Fe4[Fe(CN)6]3 · xH2O, CAS 14038-43-8), a cubic lattice of alternating Fe2+ and Fe3+ ions bridged by ligands, responsible for its deep blue color via intervalence charge transfer. Functional groups known as auxochromes modify the chromophoric system in organic colourants by extending conjugation or altering , thereby intensifying color and shifting absorption wavelengths. Common auxochromes include hydroxyl (-OH) and amino (-NH2) groups, which donate electrons to the , enhancing bathochromic shifts; for instance, the -OH groups in augment its red absorption compared to unsubstituted . Stability against environmental factors varies across classes, influencing their suitability for applications. Azo dyes generally exhibit moderate stability, with photodegradation accelerated by UV exposure and oxygen, leading to cleavage of the azo bond, though substituents like groups can improve resistance. demonstrate superior thermal and oxidative stability due to their resonant aromatic structure, resisting heat up to 300°C and chemical oxidation better than azo counterparts. Phthalocyanines offer excellent and heat fastness, with maintaining integrity under prolonged UV irradiation and temperatures exceeding 500°C owing to its robust . Inorganic classes excel in overall durability; metal oxides like Fe2O3 show high resistance to , heat (stable above 1000°C), and oxidation due to their , while complex salts such as withstand oxidation but may fade under intense from cyanide disruption. A specific example from the azo class is (E102, trisodium 5-hydroxy-1-(4-sulfonatophenyl)-4-(4-sulfonatophenylazo)-H-pyrazole-3-carboxylate, CAS 1934-21-0), a pyrazole-based used in , featuring two sulfonate auxochromes for water solubility and yellow pigmentation via extended conjugation.

Production Methods

Natural Colourants Production

Natural colourants are primarily sourced from biological and mineral origins, encompassing , animals, and minerals. Plant-derived colourants, such as from ( longa), provide yellow hues and are extracted from roots or rhizomes. Animal sources include insects (Dactylopius coccus), which yield for red pigments through processing of dried female insects. Mineral-based colourants, like kaolin clay, serve as white pigments and are obtained by and clay deposits. Extraction methods for natural colourants vary by source but commonly include solvent extraction and fermentation to isolate pigments efficiently. Solvent extraction often employs ethanol to draw out betalains from beetroot (Beta vulgaris), achieving high yields of red-violet pigments through diffusion in aqueous-alcoholic solutions at controlled temperatures. Fermentation, particularly solid-state processes, is used for fungal colourants like monascus red, where the mold Monascus purpureus is cultured on substrates such as rice to biosynthesize red azaphilone pigments over several days. Following extraction, processing involves several steps to prepare colourants for commercial use, including grinding raw materials to increase surface area for better yield, purification via or to eliminate non-pigment impurities, and to ensure consistent potency, such as concentrating extracts to 10-20% active for food-grade applications. These steps enhance stability and compliance with quality standards, often incorporating or encapsulation to prevent degradation. Production of natural colourants encounters significant challenges, including seasonal variability in raw material availability due to climate dependencies, which can disrupt supply chains for plant-based sources. Low yields further complicate scalability; for instance, obtaining 1 kg of saffron crocin requires manual harvesting from roughly 150,000 flowers, reflecting the labor-intensive nature and economic constraints of such crops. Advancements since the have introduced enzymatic extraction techniques, utilizing enzymes like cellulases or pectinases to break down cell walls, thereby improving release efficiency by 20–30% for certain pigments like anthocyanins compared to traditional methods while minimizing solvent use and energy consumption. These innovations, often combined with or assistance, address yield limitations and promote sustainable processing for sources like anthocyanins and betalains. Recent developments as of 2024 include microbial using engineered microorganisms to produce nature-identical colorants, enhancing and consistency.

Synthetic Colourants Production

Synthetic colourants are primarily produced through controlled chemical reactions that assemble complex molecular structures capable of absorbing specific wavelengths of . Unlike natural colourants derived from biological sources, synthetic production relies on starting from feedstocks or simple aromatic compounds, enabling precise control over color properties and scalability for industrial demands. The processes typically involve multi-step reactions conducted under controlled conditions to ensure high purity and yield, with global production of approximately 800,000 tons annually to meet applications in textiles, inks, and plastics. A key synthesis route for azo dyes, which constitute over 70% of synthetic colourants, is diazo coupling. This involves first diazotizing an derivative with in acidic medium to form a diazonium salt, followed by coupling with an activated such as phenol or another to yield the azo linkage (-N=N-). For example, coupling a diazonium salt from with β-naphthol produces Orange II, a common . This is typically performed at low temperatures (0-5°C) to prevent of the unstable diazonium . For vat dyes like indigo, synthesis proceeds via oxidation of an indoxyl intermediate. In the industrial Heumann process, N-phenylglycine is fused with sodium hydroxide at high temperatures (200-250°C) to form sodium indoxyl, which is then oxidized by air or oxygen to precipitate indigo. This method, developed in the late 19th century and refined by BASF, allows for high-purity synthetic indigo used predominantly in denim dyeing. Industrial manufacturing of synthetic colourants employs both batch and continuous reactors, selected based on reaction kinetics and scale. Batch reactors, common for complex multi-step syntheses like azo dyes, offer flexibility for varying products but require downtime for cleaning, leading to lower throughput. Continuous flow reactors, increasingly adopted for azo dye production since the 2010s, enable steady-state operation with reduced solvent use and reaction times, potentially lowering costs by up to 4.7 times compared to batch methods through precise control of mixing and temperature. Purification follows synthesis, typically via crystallization from aqueous or alcoholic media to isolate the crude dye, or chromatography for high-purity analytical standards, ensuring removal of unreacted intermediates and byproducts. Key reactions modify dye properties for specific applications. Sulfonation introduces -SO₃H groups using fuming , enhancing water solubility for reactive and acid dyes by increasing ionic character and preventing aggregation in aqueous solutions. For instance, sulfonation of azo compounds derived from yields direct dyes like , which bind to cellulosic fibers without mordants. Halogenation, such as chlorination of , improves lightfastness and thermal stability by electron-withdrawing effects that shift absorption spectra toward greener hues; chlorinated (Pigment Green 7) contains 12-15 atoms per , enhancing resistance to . Scale-up from laboratory (gram-scale) to industrial production (tons per batch) involves optimizing reactors, catalysts, and energy inputs. often serves as a catalyst or medium in sulfonation and diazotization steps, facilitating and reaction rates while being recycled to minimize waste. varies by dye class, driven by heating, stirring, and in exothermic or endothermic processes. Recent advances emphasize principles to reduce environmental impact. Microwave-assisted synthesis, implemented post-2020, accelerates and sulfonation by uniform volumetric heating, shortening reaction times from hours to minutes and cutting waste by 20-50% through lower solvent volumes and higher yields. For example, methods for azo disperse dyes achieve 80-95% yields in or , avoiding hazardous catalysts and aligning with sustainable manufacturing goals.

Applications

Textiles and Fibers

Colourants play a crucial role in the textile industry, where they are applied to fibers and fabrics to impart durable coloration. Dyeing methods primarily include exhaust dyeing, a batch immersion process where textiles are submerged in a dye bath containing colorants, auxiliaries, heat, and solvents until the dye is largely absorbed by the material. Continuous padding, an alternative technique, involves passing the fabric through a dye solution via rollers, followed by drying and fixation, enabling high-speed production for large volumes. Mordants, such as aluminum potassium sulfate (alum), are often employed to enhance fixation, particularly for natural dyes on cellulosic fibers like cotton, by forming coordination complexes that bind the colorant to the substrate. Fiber-specific colourants are selected based on the of the material to ensure optimal uptake and durability. Acid dyes, which attach to protein fibers like through ionic and hydrogen bonding, are commonly used for animal-derived textiles, providing vibrant shades with good affinity under acidic conditions. For cellulosic fibers such as , reactive dyes form covalent bonds with hydroxyl groups, typically via reactive moieties like the vinyl sulfone group (-SO₂CH₂CH₂OSO₃H), which undergoes in alkaline media to create permanent attachments. Disperse dyes, non-ionic and water-insoluble, are suited for hydrophobic synthetics like , where they diffuse into the matrix during high-temperature immersion or carrier-assisted processes. Performance of coloured textiles is evaluated through standardized fastness tests to ensure resistance to external factors. Color fastness to is assessed using ISO 105 methods, such as ISO 105-C06, which simulate laundering conditions and rate dye bleeding or fading on a scale of 1-5. fastness, critical for outdoor or exposed fabrics, is measured via AATCC 16, exposing samples to xenon-arc and grading color change against wool standards. These metrics guide selection; for instance, disperse dyes on typically achieve wash fastness ratings of 4-5 and fastness of 5-7, balancing with longevity. The sector consumes approximately 1 million tons of annually in the , accounting for 60-70% of global production and underscoring the scale of coloration processes. Innovations in digital printing using inks have transformed application methods, offering on-demand coloration with reduced environmental footprint. This technology applies dispersions directly via inkjet heads, eliminating traditional wet processing steps and cutting water usage by up to 95% compared to conventional exhaust or .

Food and Beverages

Colourants play a vital role in the food and beverages industry by enhancing visual appeal and compensating for color variations during processing. In the United States, the (FDA) approves specific synthetic colourants under the FD&C (Food, Drug, and Cosmetic) certification, such as FD&C Yellow No. 5 (), which is commonly used in beverages to impart a bright yellow hue. Natural colourants, exempt from certification, include (E160b), derived from the seeds of the achiote tree, widely applied in products like cheese and to achieve orange tones. These approved colourants must meet strict purity and safety standards before incorporation into edible products. Incorporation methods for colourants in food and beverages prioritize uniformity and stability. Direct addition is prevalent for water-soluble synthetic dyes like , typically at concentrations of 8–17 mg/L (approximately 0.0008–0.0017%) in sodas to ensure even distribution without altering flavor. For natural colourants prone to degradation, encapsulation techniques—such as with natural polymers like or alginate—protect against environmental factors, enabling controlled release and improved in products like yogurts and juices. Functionally, colourants mask processing-induced defects, such as in juices, while enhancing consumer appeal through vibrant, consistent shades that signal freshness. is critical for aqueous applications; water-soluble options like anthocyanins from berries are preferred for juices to dissolve fully without , maintaining clarity and homogeneity. Global consumption of synthetic food colourants reflects their widespread use despite a shift toward alternatives. The natural food colourants market has exhibited robust growth, with a (CAGR) of approximately 7.5% from 2025 to 2034, driven by consumer demand for clean-label products. During processing, colourants undergo heat stability testing to ensure they withstand conditions like at 100°C for short durations, preventing color fading in heat-treated beverages and items. This evaluation confirms their suitability for high-temperature applications without compromising product quality.

Cosmetics and Personal Care

Colourants play a crucial role in and , providing aesthetic enhancement while adhering to strict standards for contact. Common types include inorganic pigments such as s, which are widely used in for their stability and natural tones; for instance, CI 77499 (black ) imparts depth to shades, while CI 77491 (red) and CI 77492 (yellow) create warm hues. Organic lakes, like D&C Ca Lake (CI 15850:1), are prevalent in lipsticks for vibrant, long-lasting color due to their insolubility in water, ensuring adhesion to oily surfaces. In , colourants are selected based on and compatibility with product bases; oil-soluble dyes, such as D&C Yellow #11, integrate seamlessly into creams and formulations like lip balms, preventing separation and ensuring uniform distribution. Mica-based pearlescent pigments, often coated with , are incorporated into eyeshadows to achieve shimmering effects through light reflection, with particle sizes typically ranging from 10 to 60 microns for optimal luster without compromising blendability. Performance attributes prioritize skin safety and durability, including UV stability to prevent fading under sunlight exposure, as seen in iron oxides that maintain color integrity in outdoor conditions, and non-staining properties that minimize transfer onto clothing. Regulations, such as those in Annex IV, impose limits on usage; for example, certain nano colorants like (CI 77266) are capped at a maximum concentration of 10% w/w, excluding applications risking lung exposure, to ensure consumer safety. Market trends reflect a shift toward clean beauty, with increasing adoption of plant-derived colourants like extract in blushes for its natural red pigmentation and benefits, driven by consumer demand for sustainable, non-synthetic options. The global cosmetic color market is projected to grow from approximately USD 47.9 billion in to USD 68.6 billion by 2032, underscoring this transition. Application techniques involve pigment grinding to micron-scale particles—often below 2 microns for 90% of the dispersion—to achieve even coverage and smooth texture in products like .

Paints, Inks, and Plastics

Colourants play a crucial role in paints, inks, and plastics, where they are incorporated to provide aesthetic appeal, opacity, and functional properties such as UV protection. In these applications, colourants must withstand mechanical processing, environmental exposure, and long-term durability on non-absorbent substrates like metal, , and molded polymers. Dispersion techniques ensure uniform distribution, while performance metrics like weatherfastness and migration resistance determine suitability for industrial-scale use. Dispersion of colourants in paints involves milling pigments into binders to achieve homogeneity and stability. For instance, three-roll mills are commonly used to grind into resins, which serve as binders in solvent-based architectural and industrial coatings, ensuring fine particle sizes below 10 microns for optimal flow and coverage. In plastics, masterbatches—concentrated pellets of dispersed in a carrier —are fed directly into injection molding machines, allowing precise coloration during the melting and forming process without agglomeration. This method supports high-throughput production, with pigment loadings typically at 20-50% in the masterbatch before dilution to 1-5% in the final . Organic colourants, such as reds (e.g., Pigment Red 122), are favored for their vibrant hues and transparency in paints and inks, enabling clean mixing and high chroma in decorative applications. Inorganic colourants like (TiO₂) provide essential opacity and whiteness, often loaded at 10-20% by weight in paint formulations to achieve over dark substrates. These inorganic particles scatter light efficiently, contributing to brightness in both and water-based systems. Performance requirements emphasize durability, with weatherfastness evaluated through standards like ASTM D4303, which exposes coated samples to xenon arc light and measures color change (ΔE) after 100-500 hours to classify pigments as lightfast (Category I or II). In plastics, migration resistance prevents colourants from bleeding into adjacent materials, tested via DIN 53775 by contacting colored samples with unpigmented PVC under heat and pressure; high-resistance pigments like Hansa yellows maintain integrity without staining. These properties ensure longevity in outdoor paints and molded goods exposed to humidity and temperature fluctuations. The industry consumes approximately 5 million tonnes of pigments annually for paints and varnishes in the 2020s, driven by and demands, with organic pigments comprising about 40% for specialty colors. Digital inks increasingly incorporate nano-pigments, with particle sizes under 100 nm enabling sharper resolution and reduced clogging in inkjet printers for graphics and textiles. Innovations in low-VOC formulations have reduced emissions by up to 50% since 2010, achieved through waterborne binders and solvent-free dispersion methods that minimize volatile organic compounds while maintaining stability. These advances support compliant, eco-efficient production without sacrificing vibrancy or .

Safety and Environmental Impact

Health and Toxicity Effects

Colourants, particularly synthetic varieties such as azo dyes, pose potential health risks through various exposure pathways, with effects ranging from acute irritation to chronic conditions like carcinogenicity. Certain azo dyes can be metabolized in the body to aromatic amines, some of which are known carcinogens, leading to concerns about long-term exposure increasing cancer risk. For instance, benzidine-based azo dyes have been associated with carcinogenic effects due to their potential to form DNA-adducting metabolites. Most approved food colourants exhibit low acute toxicity, with LD50 values typically exceeding 5 g/kg body weight in animal models; for example, tartrazine has an LD50 of 12.75 g/kg in mice, indicating it requires high doses to cause immediate lethality. Allergic reactions and sensitivities represent another significant health concern, particularly from dermal contact with disperse dyes used in textiles. These dyes, often applied to synthetic fabrics like , can cause , manifesting as eczema or severe skin irritation upon prolonged skin exposure. Disperse Blue 106 and similar compounds are among the most common culprits, triggering in sensitized individuals. In children, certain synthetic food colourants have been linked to behavioral effects, including hyperactivity; the 2007 Southampton study demonstrated that mixtures of artificial colours and increased hyperactive behavior in 3-year-old and 8/9-year-old children, with effects observed in both general and ADHD subgroups. The (EFSA) later evaluated this study, finding limited evidence of a small effect on and activity in some children. Human exposure to colourants occurs primarily through , dermal contact, and , with being the most regulated route for consumer products. For food colourants, (ADI) limits are established to prevent adverse effects; , for example, has an ADI of 7.5 mg/kg body weight per day, based on no-observed-adverse-effect levels from toxicity studies. Dermal exposure via clothing can lead to localized allergic responses, while risks are higher for occupational settings but relevant for sensitive populations near dyed materials. Historical case studies highlight the evolution of understanding colourant toxicity. In , butter yellow (4-dimethylaminoazobenzene), an used in foods, was linked to in rats after chronic oral administration, prompting early bans and influencing modern safety assessments. More recently, EFSA's re-evaluations of food colourants in the 2010s, covering additives like and , confirmed low toxicity for approved uses but identified potential concerns for some azo compounds, leading to refined exposure limits. These assessments emphasized the need for ongoing monitoring of metabolic byproducts. As of 2025, the U.S. (FDA) has banned the use of Red No. 3 () in food and ingested drugs effective January 2025 due to evidence of carcinogenic effects in animal studies, with plans announced to phase out petroleum-based synthetic food dyes by the end of 2026 to address potential health risks including hyperactivity and allergies. To mitigate health risks, alternatives such as natural colourants derived from (e.g., for reds or for yellows) are increasingly recommended, as they generally exhibit lower potential compared to synthetic dyes. These substitutes reduce the likelihood of allergic reactions and behavioral effects, though their stability and efficacy vary. Labeling of potential allergens in products containing synthetic colourants also aids in risk avoidance for sensitive individuals.

Environmental and Sustainability Issues

The production and use of colourants, particularly synthetic dyes, generate significant environmental through dyehouse effluents. Textile dyeing processes consume 100-200 liters of per kilogram of fabric, resulting in large volumes of with high biological oxygen demand (BOD) and (COD) levels, often exceeding 1,000 mg/L due to unfixed dyes and auxiliary chemicals. Azo dyes, which constitute over 70% of synthetic colourants, can degrade under anaerobic conditions in effluents to form aromatic amines, many of which are toxic, mutagenic, and carcinogenic to aquatic organisms. Persistent organic colourants contribute to in aquatic ecosystems, exacerbating long-term ecological damage. For instance, exhibits high persistence in water, with half-lives of similar reactive dyes estimated at over 40 years under neutral conditions, leading to accumulation in sediments and chains. This persistence harms aquatic life, as evidenced by studies showing 50% fish mortality (LC50) at concentrations around 100-200 ppm for common azo dyes like Basic Red-18 in species such as . Sustainability efforts in the colourant industry focus on biodegradable alternatives and to mitigate these impacts. Microbial dyes produced by , such as those from species, have gained traction since the mid-2010s for their biodegradability and lower toxicity, offering eco-friendly options for coloration without persistent effluents. As of 2025, advancements in natural and bio-based colorants, including plant-derived pigments and genetically engineered microbial systems, are increasingly adopted to reduce environmental persistence and toxicity, supported by updated EU REACH regulations enhancing controls on effluents. Dyehouse recycling programs, including and zero-liquid discharge systems, have demonstrated waste reductions of up to 40% in and chemical consumption in implemented facilities. Lifecycle assessments reveal substantial carbon footprints associated with synthetic colourant production, typically ranging from 5-10 kg CO2 equivalent per kg of , driven by energy-intensive synthesis and feedstocks. Shifting to natural colourants can reduce reliance on synthetic processes, potentially lowering use in dye sourcing by favoring organic plant-based extraction methods over chemical-intensive for synthetic precursors. Global pollution hotspots, particularly in textile hubs of and during the 2010s, illustrate the scale of river contamination from untreated effluents. Reports from this period documented severe pollution in rivers like the Buriganga and , with discharges elevating BOD levels to over 50 mg/L and introducing , leading to oxygen depletion and in affected waterways.

Regulation and Standards

United States

In the , the regulation of colourants is primarily governed by the Federal Food, Drug, and Cosmetic Act (FD&C Act) of 1938, which initially required the listing of coal-tar colors deemed harmless and suitable for use in foods, drugs, and , excluding hair dyes. This framework was significantly amended in 1960 through the Color Additives Amendments, which expanded the definition of color additives to include all pigments and expanded the safety evaluation requirements, mandating premarket approval based on comprehensive safety data. A key provision of these amendments is the Delaney Clause, which prohibits the approval of any color additive found to induce cancer in humans or animals through ingestion, leading to actions such as the 2025 revocation of FD&C Red No. 3 for food and ingested drug uses due to its carcinogenic effects in animal studies. The Food and Drug Administration (FDA) oversees the approval and certification of colourants for use in foods, drugs, cosmetics, and medical devices. For food applications, the FDA has approved nine synthetic color additives subject to batch certification, listed in 21 CFR Part 74, Subpart A, including FD&C Blue No. 1, FD&C Blue No. 2, FD&C Green No. 3, FD&C Red No. 40, FD&C Yellow No. 5, and FD&C Yellow No. 6, though FD&C Red No. 3 was delisted in January 2025 following its classification as a carcinogen under the Delaney Clause. Batch certification applies to straight colors (dyes and pigments) and lakes, such as FD&C lakes, where each production batch must be submitted to FDA laboratories for analysis to verify purity, strength, and composition before use, ensuring compliance with specifications in 21 CFR Parts 74 and 82. This certification process is mandatory for synthetic colourants to prevent contamination and guarantee safety in products like foods and beverages. In April 2025, the U.S. Department of Health and Human Services (HHS) and FDA announced plans to phase out all petroleum-based synthetic food dyes by the end of 2026, initiating the process to revoke authorizations for Citrus Red No. 2 and Orange B within months, and encouraging manufacturers to voluntarily phase out the remaining certified colors (FD&C Blue No. 1, Blue No. 2, Green No. 3, Red No. 40, Yellow No. 5, and Yellow No. 6) due to health concerns. The Environmental Protection Agency (EPA) regulates industrial colourant production and discharge under the Clean Water Act to mitigate environmental impacts from manufacturing effluents. For dye and pigment production, the EPA has established effluent limitations guidelines under the Organic Chemicals, Plastics, and Synthetic Fibers (OCPSF) category (40 CFR Part 414), which control discharges of toxic pollutants associated with , such as and derivatives, through standards that limit releases to navigable waters and publicly owned treatment works. These standards include prohibitions on certain hazardous wastes from production, classified as K-waste codes (e.g., K181 for wastes from the production of certain and other dyes), to prevent and in aquatic ecosystems. Safety assessments for colourants involve establishing an acceptable daily intake (ADI) through toxicological testing, primarily using animal studies to determine no-observed-adverse-effect levels (NOAELs), which are then divided by safety factors (typically 100) to set human exposure limits. The FDA requires petitioners to submit data from chronic, subchronic, reproductive, and genotoxicity studies in rodents and other species to evaluate potential health risks, including carcinogenicity, before approving a color additive. Recent state-level actions reflect ongoing concerns; for instance, in September 2024, California enacted the School Food Safety Act (AB 2316), banning six synthetic dyes (including Red 40, Yellow 5, and Yellow 6) from public school meals starting December 31, 2027, citing links to neurobehavioral effects in children supported by prior health data. The FDA's certification process begins with a color additive petition submitted under 21 CFR Part 71, requiring detailed chemical, , stability, and . Review typically takes 2 to 5 years, with an average of about 24 months from submission to final rule publication, involving expert panels for technical evaluation and public comment periods. The process incurs filing fees of $1,600 to $3,000 depending on the proposed use, but total costs, including studies and compliance testing, are estimated at $1 to $2 million per due to the extensive animal and analytical requirements. Once approved, ongoing batch fees apply, currently $0.45 per pound for straight colors and lakes with a $288 minimum.

European Union and Global Standards

In the , colourants are regulated through a comprehensive framework that ensures safety and harmonization across member states. Approved food colourants are assigned E numbers, such as E129 for , following rigorous safety evaluations by the (EFSA). This system, outlined in Regulation (EC) No 1333/2008, permits only additives deemed safe for use in specified foods at defined maximum levels. Additionally, the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) regulation, effective since 2007 under Regulation (EC) No 1907/2006, mandates the registration and assessment of all chemical substances, including synthetic colourants, to protect human health and the environment across industrial applications like textiles and . In 2003, the EU implemented a ban on azo colorants in textiles via Directive 2002/61/EC, prohibiting those that could degrade into carcinogenic aromatic amines (one or more of 22 listed), thereby setting a precautionary standard for consumer products. EFSA plays a central role in ongoing risk assessments of colourants, re-evaluating their safety based on new scientific data. For instance, in 2014, EFSA reviewed (E110) and established an (ADI) of 4 mg/kg body weight per day, confirming its safety within limits but highlighting the need for monitoring in vulnerable populations. To address potential sensitivities, Regulation (EC) No 1333/2008 requires warning labels on foods containing certain synthetic azo colours—such as (E102), Quinoline Yellow (E104), Sunset Yellow (E110), Carmoisine (E122), (E124), and Allura Red (E129)—stating that they "may have an on activity and in children." These measures reflect the EU's precautionary approach, prioritizing transparency and risk mitigation in consumer products. On a global scale, harmonization efforts are advanced by international bodies like the Commission, which endorses over 40 food colourants in its General Standard for Food Additives (Codex Stan 192-1995), providing a reference for worldwide adoption and trade facilitation. The Joint FAO/WHO Expert Committee on Food Additives (JECFA) further supports this by setting international ADIs for colourants, such as 0-7.5 mg/kg for , based on toxicological evaluations to guide safe use across borders. Trade implications arise from regulatory divergences, exemplified by bans on synthetic dyes permitted in the , which have prompted WTO consultations on broader standards to resolve non-tariff barriers. The ISO 105 series of standards offers a unified methodology for assessing in textiles against factors like light and washing, promoting consistency in global manufacturing and quality control. Under organic regulations, including Implementing (EU) 2019/2164, synthetic colourants are prohibited in organic processed foods, with only approved colourants derived from specified sources permitted to align with environmental and health priorities. Complementing this, the Globally Harmonized System (GHS) of Classification and Labelling of Chemicals, revised in its 10th edition in 2023, standardizes worldwide hazard communication for colourants, requiring pictograms, signal words, and statements for those posing risks like skin irritation or aquatic toxicity. These initiatives enhance cross-border compatibility while addressing emerging concerns in supply chains.

References

  1. https://www.essentialchemicalindustry.org/materials-and-applications/colorants.html
  2. https://www.ncbi.nlm.nih.gov/books/NBK385442/
  3. https://www.fda.gov/industry/color-additives/color-additives-history
  4. https://www.science.org/doi/10.1126/science.1211535
  5. https://www.sciencedirect.com/science/article/pii/B9780443152139000053
  6. https://www.britannica.com/technology/carmine
  7. https://www.sciencedirect.com/science/article/pii/B9780323358248000074
  8. https://www.sciencedirect.com/science/article/pii/B9780815520511000091
  9. https://pmc.ncbi.nlm.nih.gov/articles/PMC8634323/
  10. https://ranbarr.com/is-carbon-black-an-organic-or-inorganic-pigment/
  11. https://www.sensientpharma.com/difference-in-lakes-and-dyes/
  12. https://pmc.ncbi.nlm.nih.gov/articles/PMC2815939/
  13. https://www.getty.edu/conservation/publications_resources/newsletters/pdf/v34n1.pdf
  14. https://www.getty.edu/publications/mummyportraits/part-one/3/
  15. https://hmsc.harvard.edu/online-exhibits/cochineal1/mexicos-red/
  16. https://pmc.ncbi.nlm.nih.gov/articles/PMC5315675/
  17. https://exhibitions.kelsey.lsa.umich.edu/ancient-color/purple.php
  18. https://pmc.ncbi.nlm.nih.gov/articles/PMC9515588/
  19. https://magazine.jhu.edu/2011/06/01/in-alchemys-defense/
  20. https://pmc.ncbi.nlm.nih.gov/articles/PMC5533699/
  21. https://digitalworks.union.edu/cgi/viewcontent.cgi?article=1766&context=theses
  22. https://www.open.edu/openlearn/history-the-arts/history/history-science-technology-and-medicine/history-science/the-birth-synthetic-dyeing
  23. https://pmc.ncbi.nlm.nih.gov/articles/PMC4759715/
  24. https://www.chm.bris.ac.uk/motm/phthalocyanine/pbpc.html
  25. https://www.usitc.gov/publications/332/pub1166.pdf
  26. https://www.usitc.gov/publications/docs/pubs/industry_trade_summaries/pub3021.pdf
  27. https://scholarship.richmond.edu/cgi/viewcontent.cgi?article=1087&context=chemistry-faculty-publications
  28. https://www.usda.gov/about-usda/news/blog/red-white-and-blue-sustainable-domestic-dye-denim
  29. https://www.grandviewresearch.com/industry-analysis/dyes-and-pigments-market
  30. https://chem.libretexts.org/Courses/Brevard_College/CHE_202%253A_Organic_Chemistry_II/05%253A_Structural__Determination_I/5.07%253A_Conjugation_Color_and_the_Chemistry_of_Vision
  31. https://chem.libretexts.org/Courses/Brevard_College/LNC_216_CHE/08%253A_Chemistry_of_color/8.03%253A_Color_and_Constitution
  32. https://www.ossila.com/pages/chromophore
  33. https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supplemental_Modules_%28Physical_and_Theoretical_Chemistry%29/Spectroscopy/Electronic_Spectroscopy/Electronic_Spectroscopy_Basics/The_Beer-Lambert_Law
  34. https://documents.thermofisher.com/TFS-Assets/MSD/Scientific-Resources/FL53216-food-dyes-beers-law-lesson-plan-uv-vis.pdf
  35. https://justpaint.org/the-science-of-how-fluorescent-and-phosphorescent-pigments-work/
  36. https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/optical-brightener
  37. https://www.dayglo.com/resources/color-matter/fluorescent-vs-phosphorescent/
  38. https://pmc.ncbi.nlm.nih.gov/articles/PMC3647017/
  39. https://bmcchem.biomedcentral.com/articles/10.1186/s13065-024-01249-5
  40. https://pubchem.ncbi.nlm.nih.gov/compound/Methyl-Orange
  41. https://pubchem.ncbi.nlm.nih.gov/compound/Copper-phthalocyanine
  42. https://pubchem.ncbi.nlm.nih.gov/compound/518696
  43. https://www.sciencedirect.com/science/article/pii/S0143720822009214
  44. https://pmc.ncbi.nlm.nih.gov/articles/PMC8270347/
  45. https://link.springer.com/article/10.1007/s40828-022-00166-1
  46. https://pubchem.ncbi.nlm.nih.gov/compound/Tartrazine
  47. https://www.fda.gov/food/color-additives-information-consumers/color-additives-foods
  48. https://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1251&context=tsaconf
  49. https://pmc.ncbi.nlm.nih.gov/articles/PMC11606904/
  50. https://explorebioscene.com/assets/uploads/doc/5be0e-329-370.10000095.pdf
  51. https://pmc.ncbi.nlm.nih.gov/articles/PMC12394531/
  52. https://pmc.ncbi.nlm.nih.gov/articles/PMC9776543/
  53. https://patents.google.com/patent/US10982070B2/en
  54. https://pmc.ncbi.nlm.nih.gov/articles/PMC5033185/
  55. https://www.sciencedirect.com/science/article/pii/S2666154325003412
  56. https://rscolorant.com/the-challenges-in-producing-natural-colorants-overcoming-obstacles-for-sustainable-solutions/
  57. https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2025.1568094/pdf
  58. https://www.frontiersin.org/journals/pharmacology/articles/10.3389/fphar.2024.1507108/full
  59. https://www.researchgate.net/publication/282005776_Evaluation_of_various_techniques_for_extraction_of_natural_colorants_from_pomegranate_rind-Ultrasound_and_enzyme_assisted_extraction
  60. https://pubs.acs.org/doi/10.1021/acs.jafc.1c07208
  61. https://www.sciencedirect.com/science/article/pii/S136759312400053X
  62. https://www.mdpi.com/2076-3417/11/14/6255
  63. https://www.organic-chemistry.org/namedreactions/azo-coupling.shtm
  64. https://www.unb.ca/fredericton/science/_assets/documents/chemistry/axodye.pdf
  65. https://www.jchemrev.com/article_154655.html
  66. https://pubs.rsc.org/en/content/articlelanding/2021/gc/d1gc01133b
  67. https://patents.google.com/patent/US2873279A/en
  68. https://www.echemi.com/cms/659164.html
  69. https://www.sciencedirect.com/science/article/pii/S2589004222007684
  70. https://www.mdpi.com/2073-4360/14/9/1703
  71. https://epubl.ktu.edu/object/elaba:142489022/142489022.pdf
  72. https://cdn.intechopen.com/pdfs/25012/InTech-Dyeing_with_disperse_dyes.pdf
  73. https://www.researchgate.net/publication/318180298_Mordant_dye_application_on_cotton_optimisation_and_combination_with_natural_dyes
  74. https://www.dharmatrading.com/home/did-you-know-how-acid-dye-works.html
  75. https://repository.lib.ncsu.edu/bitstreams/b21bf6d9-4569-4d48-b75a-5799ad64a87b/download
  76. https://www.haohuachemical.com/high-washing-fastness-disperse-dyes.html
  77. https://www.accio.com/plp/polyester-dyes
  78. https://journals.sagepub.com/doi/full/10.14504/ajr.6.5.2
  79. https://rawshot.ai/statistic/textile-dyeing-industry/
  80. https://www.marketsandmarkets.com/Market-Reports/textile-dye-market-226167405.html
  81. https://www.fespa.com/en/news-media/the-environmental-benefits-of-waterless-digital-textile-print-ink-systems/
  82. https://www.fda.gov/industry/color-additives/summary-color-additives-use-united-states-foods-drugs-cosmetics-and-medical-devices
  83. https://www.cabidigitallibrary.org/doi/pdf/10.5555/20203243371
  84. https://onlinelibrary.wiley.com/doi/10.1111/cote.12393
  85. https://roha.com/choosing-the-right-food-coloring-agents-a-meticulous-science-sans-guesswork/
  86. https://www.towardsfnb.com/insights/natural-food-colorants-market
  87. https://na.sensientfoodcolors.com/research-development/enhancing-heat-stability-in-key-natural-colors/
  88. https://www.fda.gov/cosmetics/cosmetic-ingredient-names/color-additives-permitted-use-cosmetics
  89. https://www.plumescience.com/a/blog/cosmetic-colorants-what-you-need-to-know
  90. https://nyscc.org/blog/cosmetic-colorants/
  91. https://www.makingcosmetics.com/PGOG-RED7-01.html
  92. https://www.sensientindustrial.com/na/products/certified-colorants-oil-soluble-dcs
  93. https://www.fromnaturewithlove.com/soap/product.asp?product_id=DCYELLOW11OIL
  94. https://nyscc.org/blog/multifaceted-dimensions-of-special-effect-pigments/
  95. https://www.sunchemical.com/newsrelease-nysd2025/
  96. https://www.dic-global.com/en/news/2025/products/20250709110251.html
  97. https://ec.europa.eu/growth/tools-databases/cosing/reference/annexes/list/IV
  98. https://plantmakeup.com/products/beetblush
  99. https://www.credenceresearch.com/report/natural-cosmetic-color-market
  100. https://allanchem.com/colorant-dispersion-best-practices/
  101. https://www.paint.org/wp-content/uploads/2021/09/TiO2_Feb-2013.pdf
  102. https://www.pigments.com/wp-content/uploads/DCL-Plastics-Brochure-2024-1.pdf
  103. https://tile.loc.gov/storage-services/service/gdc/gdcosrdmicrofilmpublic/2020673285/2020673285.pdf
  104. https://digitalcommons.calpoly.edu/context/theses/article/2838/viewcontent/MollyBurns_Thesis2016_Aug17.pdf
  105. https://www.teknorapex.com/en-us/teknor-apexs-extensive-product-portfolio-of-vinyl-thermoplastic-elastomers-nylon-and-colorants/colorants-masterbatches
  106. https://vibrantz.com/expertise-and-solutions/organic-and-inorganic-pigments/organic-pigments/
  107. https://www.tipure.com/en/-/media/files/tipure/legacy/titanium-dioxide-for-coatings.pdf
  108. https://www.pcimag.com/articles/105225-pearlescent-pigments-in-coatings-a-primer
  109. https://justpaint.org/lightfastness-testing-at-golden-artist-colors/
  110. https://kelid1.ir/FilesUp/ASTM_STANDARS_971222/D4303.PDF
  111. https://www.european-coatings.com/news/markets-companies/tense-pigment-market-focus-on-rising-costs-and-longer-production-runs/
  112. http://www.jetcolour.com/products/nanopigments.html
  113. https://nepis.epa.gov/Exe/ZyPURL.cgi?Dockey=P1011VAN.TXT
  114. https://www.sciencedirect.com/science/article/abs/pii/S0360132314004120
  115. https://pmc.ncbi.nlm.nih.gov/articles/PMC11280921/
  116. https://doi.org/10.1016/J.FCT.2023.113935
  117. https://www.epa.gov/sites/default/files/2015-09/documents/dcb_action_plan_06232010.noheader.pdf
  118. https://www.tga.gov.au/sites/default/files/tartrazine-toxicity-1402.pdf
  119. https://pubmed.ncbi.nlm.nih.gov/23289879/
  120. https://onlinelibrary.wiley.com/doi/10.1111/cod.12001
  121. https://www.contactdermatitisinstitute.com/disperse-blue-106.php
  122. https://pubmed.ncbi.nlm.nih.gov/17825405/
  123. https://www.thelancet.com/journals/lancet/article/PIIS0140-6736%2807%2961306-3/fulltext
  124. https://www.efsa.europa.eu/en/news/efsa-evaluates-southampton-study-food-additives-and-child-behaviour
  125. https://www.efsa.europa.eu/en/efsajournal/pub/1331
  126. https://link.springer.com/article/10.1007/s40521-019-0197-5
  127. https://cancerhistoryproject.com/article/the-enduring-legacy-of-city-of-hopes-japanese-american-scientists/
  128. https://www.sciencedirect.com/topics/medicine-and-dentistry/4-aminoazobenzene
  129. https://www.efsa.europa.eu/en/press/news/160914
  130. https://efsa.onlinelibrary.wiley.com/doi/abs/10.2903/j.efsa.2010.1853
  131. https://www.fda.gov/food/color-additives-information-consumers/tracking-food-industry-pledges-remove-petroleum-based-food-dyes
  132. https://www.ewg.org/news-insights/news/2025/08/more-food-companies-plan-phase-out-harmful-dyes-heres-what-has-happened
  133. https://www.uhhospitals.org/blog/articles/2025/02/natural-alternatives-to-artificial-food-coloring
  134. https://www.researchgate.net/figure/Average-water-consumption-for-various-types-of-fabric_tbl5_281104248
  135. https://bestcolorfulsocks.com/blogs/news/water-consumption-in-textile-industry-statistics
  136. https://pmc.ncbi.nlm.nih.gov/articles/PMC9483650/
  137. https://www.sciencedirect.com/science/article/pii/S2772416625002451
  138. https://www.intechopen.com/chapters/41411
  139. https://www.researchgate.net/publication/364837919_Reduction_of_Toxic_Effects_of_Textile_Dye_Basic_Red-18_on_Tilapia_Fish_by_Bioremediation_with_a_Novel_Bacterium_Mangrovibacter_yixingensis_Strain_AKS2_Isolated_from_Textile_Wastewater
  140. https://asm.org/articles/2017/november/bacterial-dyes-in-fashion
  141. https://www.mdpi.com/2673-4079/6/3/23
  142. https://www.supplysidefbj.com/colors-flavors/food-manufacturers-face-challenges-as-red-no-3-synthetic-dyes-face-bans
  143. https://journals.sagepub.com/doi/10.1177/00405175241247806
  144. https://journals.sagepub.com/doi/10.1177/24723444231212954
  145. https://www.mdpi.com/2071-1050/11/7/1951
  146. https://pmc.ncbi.nlm.nih.gov/articles/PMC7892934/
  147. https://www.fda.gov/food/hfp-constituent-updates/fda-revoke-authorization-use-red-no-3-food-and-ingested-drugs
  148. https://www.hhs.gov/press-room/hhs-fda-food-dyes-food.html
  149. https://www.epa.gov/sites/default/files/2015-09/documents/ocpsf-final-rule_nov-5-1987_52-fr-42522.pdf
  150. https://www.epa.gov/sites/production/files/2016-01/documents/dyes-ffs.pdf
  151. https://www.fda.gov/files/food/published/Toxicological-Principles-for-the-Safety-Assessment-of-Food-Ingredients.pdf
  152. https://www.ewg.org/news-insights/news-release/2024/09/california-leads-nation-first-ban-six-harmful-food-dyes-school
  153. https://www.fda.gov/regulatory-information/search-fda-guidance-documents/guidance-industry-questions-and-answers-about-food-additive-or-color-additive-petition-process
  154. https://www.ecfr.gov/current/title-21/chapter-I/subchapter-A/part-70
  155. https://www.federalregister.gov/documents/2024/11/08/2024-25974/color-additive-certification-increase-in-fees-for-certification-services
  156. https://www.compliancegate.com/azo-dye-regulations-european-union/
  157. https://www.efsa.europa.eu/en/press/news/140715
  158. https://www.fao.org/food/food-safety-quality/scientific-advice/jecfa/jecfa-additives/en/
  159. https://www.tandfonline.com/doi/full/10.1080/19440049.2016.1274431
  160. https://unece.org/sites/default/files/2023-07/GHS%2520Rev10e.pdf
Add your contribution
Related Hubs
User Avatar
No comments yet.