Tone Value Increase Target Derivation for Uncoated Papers
Deriving uncoated paper TVI targets demands separating optical light scattering from capillary ink absorption using M1 spectral data to set inverse RIP curves.
Print Density Yield
Optical Density
Logarithmic reflectance measurement quantifies light absorption of printed ink films on paper substrates. Reflection densitometers compare reflected light intensity from unprinted substrate against printed ink patches across standard spectral bands. Measuring print density yield establishes ink film thickness efficiency relative to pigment mass applied per unit area.
Pressroom quality control programs utilize density target values to maintain consistent color saturation across production runs.
Pigment Saturation
Ink film thickness increases raise optical density until pigment saturation reaches a physical plateau. Highly concentrated ink formulations achieve target optical density at lower wet film thickness values. Base paper smoothness and brightness influence maximum obtainable density, with coated stocks achieving higher values than porous uncoated papers.
Solid ink density measurements monitor ink film thickness variations during offset, flexographic, and gravure press operations. Print density yield evaluations optimize ink formulation cost against visual color strength requirements. Densitometer readings guide press operators in adjusting ink key settings across web widths to maintain solid color uniformity.
Achieving high density at low film thickness reduces ink drying times and prevents set-off in stacked sheets.
Saturation Limit
Excess ink application past maximum density points causes ink smearing, tracking, and prolonged drying times without increasing color saturation. Substrate surface micro-roughness scatters reflected light, capping maximum achievable optical density regardless of ink layer thickness. Highly absorbent recycled fibres lower density yield by pulling ink pigments into internal void layers.