In the world of engineering technology and product development, pressure is a critical parameter that is omnipresent yet elusive. Whether it is the tightness of engine bolts or the uniformity of contact between a tire and the ground, the magnitude and distribution of pressure directly affect equipment performance, safety, and service life. While electronic sensors are undoubtedly precise, their deployment in complex working conditions, confined spaces, or harsh environments is often prohibitively difficult and costly. Pressure-sensitive paper, with its unique "pressure visualization" capability and exceptional cost-effectiveness, has become an indispensable inspection tool for engineers.