Dot gain, or TVI (tonal value increase), is a phenomenon that causes printed material to look darker than intended. This happens because the diameter of halftone dots increases during the prepress and printing process. It also refers to an optical dot gain because dots on paper absorb more light than their physical area would suggest due to a scattering of reflected light within the paper.
TVI is related to effective dot area (EDA) as follows: TVI is equal to EDA minus the input file tint value. For example, if the input file tint is 50%, and the printed result has 70% EDA, then the TVI is 20%.
网点增益或 TVI（色调值增量）是一种导致印刷材料看起来比预期更暗的现象。 导致此现象的原因是，在印刷和印刷过程中半色调网点的直径增大。 它也称为光学网点增益，由于纸张内存在散射的反射光，与物理区域建议的光量相比，纸张上的网点将吸收更多光线。