Organic pigments are insoluble organic substances, which are usually added to the substrate in a highly dispersed state to make the substrate colored. Its fundamental difference from dyes is that dyes can be dissolved in the dye medium used, while pigments are insoluble in both the medium in which they are used and the substrate being dyed. Many pigments and dyes have the same chemical structure.
Different methods of use can transform them into each other. For example, some vat dyes and sulfur vat dyes can be used as fiber dyes if they are reduced to leuco; If not restored, they can be used as a pigment for advanced inks. Organic pigments are widely used in the raw pulp coloring of inks, paints, coatings, and synthetic fibers, as well as the pigment printing of fabrics, and the coloring of plastics, rubber, and leather, among which the ink pigment is the most widely used.
Physical Property of Organic Pigments
- Organic pigments are bright in color, strong in tinting power, and non-toxic, but the light resistance, heat resistance, solvent resistance, and migration resistance of some varieties are often inferior to those of inorganic pigments.
- The variety of organic pigment colors is endless and colorful, but there is a certain internal relationship between various colors. Each color can be determined by three parameters, namely hue, lightness, and saturation.
- Hue is a feature that distinguishes colors from each other. It is determined by the chromatographic composition of the light source and the feeling of each wavelength emitted from the object's surface on the human eye. It can distinguish red, yellow, green, blue, purple, and other features.
- Luminance, also known as brightness, is the characteristic value representing the change in the brightness of the object's surface; By comparing the lightness of various colors, colors can be bright and dark.
- Saturation, also known as chromaticity, is a characteristic value that represents the intensity of the color on the surface of an object, making the color bright and dark.
- Hue, lightness, and saturation form a solid. Using these three to establish the scale, we can use numbers to measure color. The colors in nature vary greatly, but the most basic ones are red, yellow, and blue, which are called primary colors.