Orange-red is a vivid color that grabs attention. But what pigment produces this bright hue? The answer lies in understanding how color works at the chemical level. Red and yellow are primary colors that can be combined to make orange. The specific pigments used to make paint or dyes orange-red depend on the medium and desired qualities. Understanding pigment chemistry sheds light on why some shades appear more red or more yellow.
The Color Wheel
The color wheel illustrates how primary colors can be mixed to create secondary and tertiary colors. Red, yellow, and blue are primary colors. Orange is a secondary color made by combining red and yellow. Red and yellow are located opposite each other on the color wheel. Combining pigments from opposite sides creates vibrant secondary colors.
Tertiary colors are made by mixing a primary and adjacent secondary color. Red-orange contains mostly red with some yellow. Yellow-orange contains mostly yellow with some red. Adjusting the proportions shifts the hue toward red or yellow.
Light versus Pigment
Color can be produced using light or pigment. Computer screens create color with light. Red, green, and blue light combine to make other colors. Paints, dyes, and inks use pigments to absorb some wavelengths and reflect others. A red pigment absorbs green and blue light, reflecting just red. Combining pigments creates new reflected colors.
Orange paint uses red and yellow pigments. More red pigment shifts toward red-orange. More yellow makes yellow-orange. Light and pigments mix colors differently, but both follow the same color wheel relationships.
Natural and Synthetic Pigments
Many natural pigments have been used since ancient times. Red ochre is a natural clay containing iron oxide that produces an orangey red. Safflower and turmeric contain carotenoids that dye fabrics yellow and orange. Paprika and saffron add similar colors to food. These sources vary in color and permanence.
Modern hues come from synthetic pigments engineered for brightness and durability. Two key types create orangey reds:
Azo pigments
Azo pigments contain nitrogen and are named using “azo” plus a color. Dinitroaniline orange is an azo pigment producing a yellowish red. Pyrazolone orange is more red with a bluish tint. Manufacturers mix varying ratios to achieve desired orange-red shades.
Quinacridone pigments
Quinacridone pigments based on quinacridone molecules create intense, fade-resistant colors. Quinacridone magenta produces a strong red. Quinacridone gold makes a reddish yellow. Combining the two at different ratios gives clean orangey reds.
Paint and Ink Pigments
Many paints and inks contain blends of pigments to achieve balanced properties. Here are some examples of pigment mixes producing orangey reds:
– Alizarin crimson – alizarin (reddish) + phthalo blue (greenish)
– Cadmium red – cadmium red + cadmium yellow
– Vermilion – mercury sulfide + synthetic red
Printing inks combine pigments with oils, resins, and solvents. Newspaper ink uses organic pigments for cost, while magazine ink uses higher-quality azo and quinacridone pigments. The choice of pigments affects color consistency and printability.
Dyes and Textile Pigments
Dyes chemically bond to textile fibers to color them. Common dyes for orangey reds include:
– Madder – natural dye from roots of the madder plant
– Congo red – azo dye often used for cotton and wool
– Acid red 26 – synthetic red dye for nylon and silk
Pigments can also be applied to textiles. Red and yellow pigments are blended into printing pastes and fixed to the fabric. Textile pigments come in many forms:
– Inorganic – iron oxide, cadmium sulfide
– Organic – hansa yellow (manufactured), curcumin (from turmeric)
– Dye pigments – insoluble forms of dyes
Food Coloring Pigments
Food dyes impart color while ideally being tasteless, odorless, and non-toxic. Food manufacturers blend colors to produce visually appealing products.
Common orange-red food colorants include:
– Citrus Red 2 – azo dye made from naphthol
– Allura Red AC – red azo dye combining with yellow
– Paprika/capsanthin – natural pigment from paprika
– Carmine – red pigment from cochineal insects
Newer natural alternatives exist like anthocyanin berry extracts. Food color regulations control which pigments are considered safe.
Cosmetics Pigments
Cosmetics like lipstick, blush, and eye shadow use pigments to tint skin, lips, and eyelids. Inorganic pigments like iron oxides provide earthy red tones. Organic lakes are pigments formed by precipitating dyes onto an inert binder. Common orangey red cosmetic pigments include:
– Red 6, Red 7 – inorganic iron oxide-based pigments
– Red 28 Lake – organic pigment made from eosin dye
– Carminic acid Lake – organic pigment from cochineal insects
– Mica coated with red/yellow pigments
Mineral makeup products apply fine pigment particles using mica coated with iron oxides or organic pigments.
Conclusion
Orange-red arises from the interaction of red and yellow pigments. Natural sources provide a starting point, but modern synthetic organic pigments create bright, durable orangey reds. Manufacturers select and blend pigments to produce colors with optimized properties for the intended application, whether paints, plastics, textiles, foods or cosmetics. The chemistry behind these colors makes orange reds eye-catching across many different products and materials.
| Pigment Type | Examples |
|---|---|
| Natural earths/minerals | Red ochre, iron oxide |
| Plant-based | Madder, turmeric, safflower |
| Animal-based | Carmine, cochineal |
| Synthetic inorganic | Cadmium red |
| Synthetic organic | Azo, quinacridone |
