关键词: 印文墨迹；积分光密度法；历时变化

Abstract: Objective Explore the feasibility of using the integrated optical density value to judge the formation time of inscriptions. Methods Through the experiment， using Image-pro plus software to collect and record the integrated optical density data of the experimental samples of different time periods, and using the relevant data and analysis method to count and analyze the integral optical density data of three kinds of brand printing oil and printing mud cover inscriptions. Results It was found that the numerical value decreased rapidly during the period of 1-120 d, and the it decreased slowly during the period of 120-380 d. The value basically tends to be stabilized after 380 d. Conclusion it is considered that the integral optical density value of the inscription decreases with the increase of the formation time, and the numerical value tends to be stable after a certain time ,and the correlation is more obvious within 120 d.

Key words: printed ink; inetgral optical density ; forming time