Optimization Study of Quadratic Regression Model for Offset Solid Density

Quantitative relationships among solid density, dot gain, and relative contrast in offset printing were examined using quadratic regression modeling. By designing a scientific experimental program, 20 printed samples with fields of 50% and 75% dots were collected and accurately measured using a spectrophotometer. A quadratic regression model for four-color ink was developed using response surface analysis, emphasizing the nonlinear effects and interactions among parameters. Analysis showed all regression models achieved high significance (p < 0.001), with coefficients of determination (R2) exceeding 0.85, indicating excellent fit and predictive power. The optimal solid density parameters for the four-color inks were identified through extreme value analysis: yellow, 0.990; magenta, 1.330; cyan, 1.420; and black, 1.750, where the relative contrast peaks. These findings provide a scientific basis for optimizing offset solid density and serve as valuable guidance to improve the quality and consistency of printed materials.