Composition and application of synthetic and natural pigments 5

Pigments are substances that give color to objects. Pigments are soluble and insoluble, inorganic and organic. Inorganic pigments are generally mineral substances, and humans have known to use inorganic pigments for a long time, using colored earth and ores to paint and smear the body on rock walls.

Organic pigments are generally derived from plants and marine animals such as madder indigo, garcinia cambogia and purple from shellfish in ancient Rome. Soluble pigments, also called dyes, can be used to directly print and dye fabrics with solutions. Insoluble pigments should be finely ground and added to the medium, such as oil, water, etc.

It is then applied to the surface of the object to be dyed to form a blanket layer. In modern times, there are many synthetic chemical pigments that can meet the needs of human beings when they need to divide the hue in detail, such as painting, which requires many different pigments with very small differences.

The basic requirements of pigments for art are the finer the particles, the better the color, and the longer the color does not change (the stability should be good).

Watercolor paints are almost always transparent except for white. In this way, the needs of watercolor over-dyeing can be met.

Gouache pigments were originally invented by adding white powder to watercolor pigments to make the colors opaque. Since watercolor paint is transparent, it is difficult to correct it if you make a mistake. Gouache pigments, on the other hand, can be easily modified due to their opacity.

Later, raw materials such as gum arabic were added to the gouache pigment to further improve its performance. Gum arabic can give gouache paint a glossy surface after drying, but in special situations where flat coating is required (such as painting renderings and coloring animations), the gum can form irregular spots on the color surface or make the color uneven, so there are special degumming pigments.

Oil paint is the dilution of pigment with oil.

Chinese painting pigments are very rich, and there are various types, from mineral powder to plant extraction to animal extraction, and the types are complex.

Theoretically speaking, as long as there are red, yellow and blue primary colors, all other colors can be tuned, but the purity of the color is always not high enough, so modern art pigment manufacturers produce high-purity pigments for various hues and brightness colors to meet various needs. From the most basic 12 colors to the usual 24 colors or even 48 colors to more than 60 colors. Special metallic colors are not included.

Synthetic pigments are not very clear.

Natural pigments know some.

Cyanine: Jianqing Dai dissolves (pharmacies may have).

Gardenia yellow: Raw gardenia mashed, peeled and fried in water.

Huaihuang: Blanch the rice with boiling water, knead it into a cake, and twist it out with a cloth.

Limestone: Azurite ground (very little).

These are what I saw in the issue of "Chinese Heritage".

While we can define a color as the sum of all these spectrums, different animals see different colors and different people perceive different colors, so this definition is quite subjective.

Definition of color:

Color is a visual effect on light that is produced through the eyes, the brain, and our life experiences. A person's perception of color is not only determined by the physical properties of light, for example, the human perception of color is often affected by the colors around it. Sometimes people also refer to the physical properties of matter producing different colors directly as colors.

The wavelength and intensity of electromagnetic waves can vary greatly, and in the range of wavelengths that a person can perceive (about 380 nanometers to 740 nanometers), it is called visible light, and sometimes referred to simply as light. If we list the intensities of the wavelengths of a light source together, we can get the spectrum of that light source. The spectrum of an object determines the optical properties of the object, including its color.

Different spectra can be received by humans as the same color. While we can define a color as the sum of all these spectrums, different animals see different colors and different people perceive different colors, so this definition is quite subjective.

A surface that diffusely reflects all wavelengths of light is white, while a surface that absorbs all wavelengths of light is black.

Color is people's perception of light, so black is people's perception of no light, and it can be said that black is not a real color.

Each color represented by a rainbow contains only one wavelength of light. We call such colors monochromatic. The spectrum of the rainbow is actually continuous, but generally people divide it into seven colors:

Red, orange, yellow, green, cyan, blue, purple, but each person always divides them slightly differently. The intensity of monochromatic light also affects how a person perceives the color of a wavelength of light, for example, dark orange yellow is perceived as brown, and dark yellow-green is perceived as olive green, and so on.

Opaque objects take on the color of the light they reflect!

Transparent objects take on the color because they absorb the corresponding light!

The composition of pigments can be mainly divided into substrates and chromants.

Chromants provide the desired color and require high chemical stability. Most of them are purified natural minerals containing metal oxides. Many pigments have a description of their composition on their names, such as zinc titanium dioxide, cobalt blue, etc.

The function of the matrix is to provide the desired blending, clarity requirements, coating functionality, drying volatility, and long-term durability. According to the chemical properties, it can be roughly divided into two types: water and oil, and according to the physical properties, it can be divided into different forms such as liquid, semi-liquid, paste, and wax.

There are also additives that can be used to improve dilution, permeability, etc., which can also be included in the category of matrix.

The pigment made of lead field code made of colored organic acacia compound as the raw material of the spine shed is called organic pigment.

Refers to a class of pigments made from organic compounds that have color and a range of other pigment properties. Pigment properties include light resistance, water immersion resistance, acid resistance, alkali resistance, organic solvent resistance, heat resistance, crystal form stability, dispersion and concealment power. The difference between organic pigments and dyes is that they have no affinity with the object being colored, and only the organic pigment is attached to the surface of the object by adhesives or film-forming substances, or mixed inside the object to color the object.

The intermediates, production equipment and synthesis processes required for its production are similar to those required for the production of vertical dyes, so organic pigments are often organized in the dye industry. Compared with general inorganic pigments, organic pigments usually have higher tinting strength, particles are easy to grind and disperse, not easy to precipitate, and the colors are brighter, but they have poor light resistance, sun heat resistance and weather resistance. Organic pigments are widely used in the coloring of inks, coatings, rubber products, plastic products, stationery and building materials.