Water-based ink has recently come into wide use for gravureand flexographic printing. Griavure printing on rough surface paper had a tendency for reduced ink transfer, especially from highlights to middle tones. On the other hand, flexographic printing is effective with paper surfaces of considerable rouuhness. Water-repelling paper or paraffin-coated paper is used for overwrapping liners. However, this kind of paper has low surface tension and the wettability of water-based ink is low. Ink transter is diminished and color strength decreases. However, ink wettability is improved by decreasing its surface tension as much as possible. On non-coated paper, water-based inks dry well by penetration into the paper. But in the case of coated paper, or multicolor printing, drying occurs mainly by evaporation and large amount of energy is required.