Dot etching: Colour correcting on screened colour separations by dissolving the outer edges of half-tone dots with chemical to change the size of the dots so as to achieve the required tonal balance.

• 网点腐蚀:用化学品在上网后的分色片上改色。它把网点的边缘蚀去，使网点变细，从而达致要求的色调平衡。