The core conflict stems from the fact that Photoshop defaults to displaying M2 L*a*b* values for digital Pantone spot colors. M2 is a UV-Excluded measurement mode that ignores the effect of Fluorescence from OBAs in paper.

However, all current printing standards and workflows require the M1 (UV-Included) mode, as it accurately simulates the color seen under standard D50 lighting. This mismatch means the color values the designer sees are fundamentally different from the values the pressroom controls, leading to high ΔE errors and reproducibility issues.