- Selection of pigment
Usage of pearl powders. Pearl pigment has obvious optical changes, from bright to soft and elegant. This special effect depends on the selection of pigment type and medium. Each series of pigments has different levels of brightness, particle size, and special color effects. However, its effect can be influenced by medium. Transparent medium can maximize the color variety of pigment. When mixed with less transparent medium, the pearlescent effect will be greatly affected. So, to mix this powder with other colorants, we should choose dyes or pigments with good transparency. - Application, such as gravure printing ink:
We can wet the pearl pigment with a small amount of solvent or ink in advance to achieve good dispersion. - Printing
The printing can be lithography, flexography, gravure printing, screen printing, or thermal relief printing. In different printing method, the application of pearl pigment varies.
The main factors that affect the pearl effect of printed products include: the nature of ink, ink transfer mode, printing process, and the type of printed material.
When used in printing ink, pearl pigment has larger particles than traditional ink pigments. So, to ensure printing quality, we need to adjust certain printing conditions. We should correct the number of lines (strips) of the transfer and gravure rollers to 75-100, and the silk screen meshes from 100 and 250 for the case of large particles, which also thickens the ink film. Therefore, it is necessary to adjust the drying temperature and pay attention to the smoothness of papers, the volatility of solvent, and the properties of colorants.
When press polished or embossed, the printed surface will have better pearly effect.
Printing on dark paper followed by embossing can produce a gift-wrapping paper with special effect. When printed and then press polished, unbleached natural kraft paper will have metallic luster.
