All About Paint: Pigments and History

• Paint is a liquid that converts to a solid film after being applied to a surface
• It protects, colors, or textures objects

Pigments

• Finely ground and practically insoluble
• Give color and opacity
• Can be organic or inorganic
• Add bulk or desired physical and chemical properties

History of Paint

• 100,000 to 3,000 BCE: Early humans used charcoal, ochre, and other natural substances mixed with animal fat or water
• 3250 to 500 BCE: Egyptians created Egyptian blue (calcium copper silicate)
• 500 BCE to 476 CE: Greeks and Romans used cinnabar (mercury sulfide) and malachite (copper carbonate)
• 19th century: Industrial advancements led to mass production and accessibility
• 1914: The first Indian-owned paint factory was established in Bombay by Shri Ladhubhai Damji Doshi, focusing on zinc oxide production
• 1940: Water-based latex paints were developed, offering quick drying and low toxicity
• 18th and 19th centuries: Synthetic pigments like Prussian blue and cadmium yellow emerged
• 20th century: Bright, stable synthetic organic pigments like phthalocyanine blue and green were introduced

Types Based on Composition

Oil-Based Paint

• Uses natural or synthetic oil, or organic solvents like mineral spirits
• Very durable and resistant to nicks, dings, and stains
• Ideal for woodwork, furniture, and exterior surfaces requiring durability and a smooth finish

Water-Based Paint

• Also called latex paints
• Consists of a pigment and a binder with water as a carrier
• Commonly used for walls, ceilings, and exterior surfaces
• Offer versatility and environmental friendliness
• Acrylic Paint: Highly durable, flexible, and resistant to cracking
• Latex Paint: Easy to apply and fast-drying
• Emulsion Paint: Offers a smooth finish and good adhesion
• Watercolor Paint: Used for artistic applications, offering transparency and blending capabilities

Types Based on Finish

Matte Paint

• Non-reflective and conceals surface imperfections
• Ideal for ceilings, low-traffic walls, and spaces where glare needs to be minimized

Satin Paint

• Soft sheen that is easy to clean and slightly reflective
• Used for living rooms, hallways, and bedrooms

Semi-Gloss Paint

• Moderately shiny and durable
• Resists moisture and stains
• Common for kitchens, bathrooms, trim, and furniture

Glossy Paint

• Highly reflective and durable
• Creates a polished look
• Used on furniture, doors, and metal surfaces needing a tough, washable finish

Types Based on Specialty

Primer Paint

• Base coat to improve adhesion of topcoats
• Seals porous materials, prevents stains from bleeding through, and enhances paint durability
• Essential for new, bare, or repaired surfaces

Anti-Corrosion Paint

• Protects metal surfaces from rust and oxidation
• Forms a protective barrier against moisture and chemicals
• Used on steel structures, pipelines, bridges, and marine equipment

Epoxy Paint

• Tough and chemical-resistant
• Used for industrial and garage floors, concrete, metal, and surfaces exposed to heavy wear

Fire-Resistant Paint

• Slows down the spread of fire
• Used in fire-prone areas like kitchens, warehouses, and commercial buildings

General Raw Materials

Pigments

• Give color and opacity
• Some prevent corrosion
• Can be organic, inorganic, natural, or synthetic

Organic Pigments

• Derived from carbon-based compounds
• Recognized for their bright colors and high tinting strength but less durable
  • Carmine (red): From cochineal insects
    • Used in cosmetics and food coloring
  • Indigo (blue): From plants, such as Indigofera tinctoria
    • A natural historical dye
  • Phthalocyanine blue (intense blue and green): Synthetic and widely used
  • Azo pigments (red/yellow): Used in dyes and coatings

Inorganic Pigments

• Made from mineral-based compounds
• Valued for durability, weather resistance, and muted tones
  • Titanium dioxide ((TiO2): Used in paints, sunscreen, and cosmetics
    • Adds opacity and UV-blocking properties
  • Iron oxide (Fe2O3, Fe3O4: red, brown, yellow): Used in paints, ceramics, and cosmetics
  • Chromium oxide (green): Stable and non-toxic

Natural Pigments

• Derived from plants, animals, or minerals
  • Ochre (Iron Oxide) – Yellow, red, brown tones
  • Umber (Manganese and Iron Oxides) – Brownish tones
  • Carbon Black - Made from burning organic materials

Synthetic Pigments

• Created through chemical processes
• Vibrant colors and stability
  • Phthalocyanine Blue/Green: Highly stable blue and green shades
  • Cadmium Red/Yellow: Intense, bright red and yellow (toxic, regulated)
  • Chrome Yellow (Lead Chromate): Deep yellow, but toxic
  • Quinacridone Magenta: Bright magenta with excellent lightfastness

Binders

• Add larger pigment particles
• Improve adhesion and strengthen the film
• Polymer, vehicle, or resin forms the film
• Glossy and clear
  • Latex (Acrylic Binders): Common in water-based paints
    • Provides a flexible and durable film
  • Polyurethane binders: Used in high-performance coatings
  • Alkyd binders: Typically used in oil-based paints
  • Cellulose-based binders: Used in industrial paints
  • Silicone binders: Used in heat-resistant and weatherproof coatings

Thinners

• Solvents used to dilute paints or coatings
• Adjusting viscosity and making them easier to apply
  • Mineral spirits (white spirits): Common solvent for oil-based paints
  • Turpentine: Natural thinner used in oil painting
  • Acetone: Used to thin some coatings and clean brushes
  • Xylene: Often used for thinning industrial paints and coatings

Anti-Skinning Agents

• Additives used to prevent the formation of a skin on the surface of the paint
  • Cobalt naphthenate: Commonly used anti-skinning agent
  • Butylated hydroxyToluene (BHT): Prevents oxidation and skinning
  • Phenolic compounds: Used in some industrial and specialty coatings

Plasticizers

• Substances to increase the flexibility and workability of paints, coatings, and films
  • Phthalates (e.g., dioctyl phthalate): Used in plastic-based paints and coatings
  • Tetrahydrofuran (THF): Used in some coatings
  • Epoxy plasticizers: Used in high-performance coatings

Extenders/Fillers

• Added in order to reduce the cost of a paint formulation

Vehicle Oil

• Refers to the medium or binder used to carry the pigment particles
• Helps particles adhere to surfaces
  • Linseed Oil: Most common vehicle oil
  • Soybean Oil: Less commonly used in art
  • Poppy Seed Oil: Used for light-colored pigments

Driers

• Chemical additives that speed up the drying process of paint
• Often metallic compounds
  • Cobalt: A fast-acting drier
  • Manganese: Fast-acting, but has a dark color
  • Iron: Promotes rapid drying by polymerization
  • Rare Earth: Useful under conditions of high humidity or low temperatures
  • Lithium: Sometimes added to other driers

Varnish

• (Optional)
• Homogenous solution of resins in oil, alcohol, or turpentine
  • Oil Varnish: Uses linseed oil and takes 24 hours to dry
    • Suitable for any application
  • Spar Varnish: Derived from its use on spars and other parts of ships
    • Gives a sticky effect in warm weather and is not used indoors
  • Spirit Varnish: Resin dissolved in spirit
    • French polish, lacquer, and shellac varnish
    • Dries quickly

Paint Manufacturing Process

• Selection of Raw Materials: choose components to meet specifications

• Mixing and Blending: mix materials in proper proportions

• Grinding and Milling: grind base paint to achieve desired consistency and smoothness

  • Commonly Used Mills:
    • Attritor
    • Ball Mill
    • Bead Mill
    • Basket Mill
    • Pebble Mill
    • Sand Mill
    • High Speed Disc Disperser

• Quality Control and Testing: evaluate physical and chemical properties

• Packaging and Shipping: packaged in containers and shipped to retailers or consumers

Requirements of Good Paint

• Covering Power
• Strong Adhesion
• Durability
• Washability and Stain Resistant
• Smooth Finish and Aesthetic Appeal
• Fast Drying Time
• Flexibility
• Corrosion and Chemical Resistant
• Good Flow and Leveling
• Low Toxicity and Eco-friendliness

Common Defects

• Blistering: Bubbles or blisters due to trapped moisture, excessive heat, or improper surface preparation
• Cracking: Visible cracks caused by aging, excessive thickness, or improper application
• Peeling: Paint detaches due to poor adhesion, moisture, or lack of surface preparation
• Chalking: Powdery residue due to breakdown of the paint binder under UV light exposure
• Fading: Loss of color intensity over time
• Sagging or Running: Uneven excess paint creates streaks or an uneven finish
• Wrinkling: Rough, crinkled surface due to cold or humid conditions, thick coats, or improper drying
• Discoloration: Unintended color changes due to chemical reactions, moisture, or staining
• Flaking: Small pieces lifting due to poor adhesion
• Spotting or Staining: Stains or spots due to contamination, water intrusion, or chemical reactions

Main Types

Decorative Paints

• Interior and exterior paints
• For residential and commercial buildings

Industrial Coatings

• High-performance coatings
• For protecting surfaces in industrial settings

Specialty Paints & Coatings

• Designed for specific purposes
  • Powder coatings
  • Wood finishes
  • Artist paints
  • Traffic paint
  • Anti-fouling paints

Pigments & Colorants

Organic Pigments

• Carbon-based compounds
• High color strength and tinting power

Inorganic Pigments

• Minerals and metal oxides
• Excellent durability, opacity, and weather resistance

Specialty Pigments

• Create unique visual effects like pearlescence, metallic sheen, or fluorescence

Dyes

• Are soluble
• Vulnerable to fading
• Don't need a binder

Pigments

• Are insoluble
• Resistant to fading
• Need a binder.

Inks & Printing Products

• Printing Inks – Liquid and less expensive, vibrant and cartridges need replacing regularly.
• Toners - Powder and more expensive and resistant to smearing, has higher print quality and requires less maintenance.

Related Products

• These are materials that the paint and pigment industry produce and that are used by other industries