Evaluation of Color Measurement Geometries for Optically Variable Inks

Optically Variable Inks (OVI) holds significant value and finds extensive application in the domain of anti-counterfeit printing. To evaluate the effectiveness of the measurement geometries prescribed by existing standards for evaluating the color-shifting feature of OVI, the experiment employed an X-Rite MA-T12 multi-angle spectrophotometer to measure and analyze the chromatic and spectral characteristics of 10 different OVI samples in 12 geometries. The findings indicate that a decrease in the aspecular angle results in higher saturation of OVI. Additionally, when the aspecular angle is ±15°, an increase in the illumination angle leads to notable changes in the hue angle of OVI. The measurement geometries of r45as-15 and r15as15 find the highest saturation and the most extensive range of hue variations for the OVI samples, exhibiting color changes that align with the manufacturer’s labels. However, when the samples were tested using the geometries specified in GB/T17001.7-2023, the optimal color-shifting effect of the ink was not evident.