History of color

Overview
Color plays a very important role in today’s world in developing human taste and inclinations and satisfying his aesthetic needs. That is why the sense of color is called the seventh sense. Man deals with color in the field of home decoration, clothing and even soft drinks, in art, painting, shipping industries and communications, consumer products in the space industry and in short in all aspects. In general, color is used in addition to creating beauty in the environment, to protect objects from natural factors, etc.

History
The history of the use of coloring materials by man dates back to the caveman era. The first real and practical use of coloring materials can be considered related to the construction of Noah’s Ark, which was used to prevent water penetration and decay. Later, coloring materials were used to protect wood from decay in wooden buildings and when the use of iron tools became common, to prevent them from rusting.
Components of Paints
Each paint is basically composed of two main parts, which are:
Pigment
A coloring matter that is insoluble in water (colored clay and snow powder from colored rocks were the first pigments used by humans).

A paint carrier
A liquid that, when mixed with the pigment, makes it easy to apply and helps it adhere (egg whites, honey glue, and sugar solution were used as paint carriers). Today, the most common pigment carriers are water or oil. Therefore, paints are divided into two categories: oil paints and organic paints.

Types of Pigments
Oxides
• Limonite (Fe2O3.2H2O) is used to prepare red paint and is one of the oldest pigments.
• Hematite (Fe2O3) is used to prepare bright red paint.
• Titanium dioxide (TiO2) is used to produce a bright, high-quality white paint that does not darken in air. It is usually mixed with barium sulfate.
• Zinc oxide (ZnO), which is one of the most important white pigments and is obtained from the decomposition of zinc carbonate or the burning of zinc metal in air.
• Lead (Pb2O3), which has a red or dark red color and is mostly used to cover the surface of steel parts to protect them from rusting.

Zinc sulfide and lythopene
Zinc sulfide is used to produce a matte white paint, and one of its advantages is that, unlike lead whitewash, it does not darken in air. This pigment is usually used commercially as a mixture of zinc sulfide and barium sulfate called lythopene, which is a very high-quality white paint.
Lead whitewash
This pigment mainly consists of Pb(OH)2, PbCO3, which has been known for centuries. Their covering power is high, but in the air it gradually turns black due to the presence of H2O. To turn it back to white, the effect of hydrogen peroxide can be used on it.
Lamp soot and bone charcoal
It is one of the components of black and mixed paint and is also used to change the white color to the desired amount.
Metallic pigments
• Such as aluminum powder in varnish, which is used to protect iron and steel items
• Aluminum bronze (Al, Cu alloy) in varnish, which is used to create a very beautiful golden color for frames and …

Colored pigments
• Blue pigments: The most important of these pigments are Prussian blue and indigo blue or lapis lazuli. Prussian blue is one of the most important blue colors. Lapis lazuli is also one of the high-quality blue colors that is obtained by heating a mixture of kaolin, sodium carbonate, sulfur and coal in the absence of air.
• Yellow pigments: The most important of these pigments are zinc chromate and lead chromate. Coal tar also produces colored pigments in the form of insoluble metal salts that are set in aluminum hydroxide as a gel. After drying, this gel is mixed in powder form with pigments such as calcium carbonate and silica and used in a variety of colors.
Oil paints
In these types of paints, the pigment is dissolved in a drying oil that is an ester of glycerin with fatty acids, such as oleic or linolenic acids. These oils oxidize in air, become saturated compounds, and form a hard, resistant, and protective layer that prevents water from penetrating the pigment.
Thinner
Used to dilute and facilitate the application of paint and is usually a hydrocarbon solvent such as turpentine, known as turpentine oil.
Dryer
A component of oil paints that actually acts as a catalyst in accelerating the oxidation and drying of paints and is usually a mixture of lead, manganese and cobalt oxides in (sulfur oil) in the form of an ester.

Plastic paints
By adding synthetic resins such as resin derived from phenol and formaldehyde, which has plastic properties, to varnish, plastic paints are obtained. These types of paints are important and have many applications due to their durability and washability.
Glaze or matte paints
By adding colors such as TiO2 to varnish, it is made matte, and then used to matte any type of paint.
Car paint
These types of paints must have the property of drying quickly in air. For this purpose, the pigment is dissolved in highly volatile organic solvents such as amyl acetate, ethyl acetate or butyl acetate. For metallic paints, metallic pigments are used.
Water-soluble paints
These types of paints are prepared by suspending pigments in water mixed with a water-soluble binder. They are cheaper than oil paints and cannot be washed off.

Industrial production of black pigment

Carbon soot is the only major black pigment. This pigment is used in the rubber industry and also as a hardener for some mechanical parts. Most printing inks are