White ink & reducer in ink formulation

In offset ink formulation, white ink and reducer are often used, but they serve distinct purposes due to their inherent properties, which operators should not confuse or interchange.

Role in Ink Formulation

White Ink: Adding a small amount of white ink to colored ink can alter its tone, softening it to create a refined and elegant appearance. This is particularly desired in packaging, as it enhances the appeal of the printed product to meet visual and psychological expectations.
Reducer: Reducer is used to adjust the depth of ink color by reducing its concentration. The more reducer added, the lighter the ink becomes, allowing flexibility in achieving the desired color intensity.

Proportion in Ink Mixtures

White Ink Proportion: White ink is one of the densest inks in offset printing. Typically, it should not exceed 20% of the total ink blend, as its heavy pigment can hinder proper transfer, leading to rough and uneven prints.
Reducer Proportion: As reducer is colorless and have favorable printing properties, they can be added without strict limits to achieve the necessary shade, offering efficient ink transfer.

Different impact on Emulsification

White ink has a stable resistance to emulsification, retaining water resistance when mixed with color ink.
Reducer, however, may reduce the ink’s water resistance, increasing emulsification, especially with higher diluent ratios.