Standardized Tone Value Increase Calibration Protocols across Variable Substrate Grades
Standardized TVI calibration requires substrate-relative spectral curves, M1 spectrophotometry, and dynamic CTP curve adjustments matched to sheet porosity.
M1 Measurement Mode
Spectral Illuminant
Spectrophotometric measurement standards under ISO 13655 define spectral energy distributions for color measurement instruments used in print and packaging workflows. The integration of optical brightening agents in paper coatings necessitates M1 measurement mode, which specifies CIE illuminant D50 with matched ultraviolet content. Standardizing UV excitation ensures consistent color evaluation across substrates containing fluorescence.
Fluorescence Response
Optical brighteners absorb invisible ultraviolet radiation and re-emit light in the blue spectrum to increase perceived whiteness. Legacy measurement conditions without calibrated UV illumination produce inconsistent spectral data when measuring brightened substrates under different viewing environments. Operating handheld or inline spectrophotometers in M1 measurement mode aligns color data collected in pressrooms with proofing booth viewing conditions specified by ISO 3664.
The standard divides M1 into two parts, where daytime viewing conditions dictate spectral match above 400 nanometers and controlled UV content governs excitation below 400 nanometers. Packaging converters printing on coated folding boxboard rely on this mode to achieve accurate spot color matching between proof and production sheet. Accurate fluorescence excitation prevents color shifts between pressroom measurements and customer quality audits.
Colorimetric Standard
Digital color communication protocols require standardized illumination data to maintain color fidelity across global packaging supply chains. Spectral data captured using M1 measurement mode forms the baseline for brand owner color tolerances and target library definitions.