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.
Solid Optical Density
Absorbance Ratio
Logarithmic reflection measurement quantifies maximum light absorption of fully saturated ink patches on printed substrates. Densitometers cast light onto a solid ink field and measure reflected light through specific narrow-band color filters. Establishing solid optical density target levels ensures consistent ink film thickness across production runs.
Quality control standards define target density ranges for process inks on coated and uncoated paper stocks.
Layer Thickness
Increased ink film thickness yields higher optical density values until pigment saturation reaches a maximum threshold. Solid density values directly correlate with visual ink color strength and printed image contrast. Target values for process black on coated sheetfed papers typically range from one point eight zero to two point zero zero optical density units.
Cyan, magenta, and yellow process inks target lower density values based on specific ISO printing standards. Substrate absorbency influences density buildup, with porous paper requiring higher ink volume to match coated sheet density. Solid optical density monitoring allows press operators to detect ink roller starvation or excessive ink feeding across press fountains.
Maintaining stable solid density prevents unwanted color shifts across long printing runs.
Reflectance Limit
Excessively high solid density leads to ink trapping failures, long drying times, and ink set-off in output delivery piles. Low density readings indicate insufficient ink transfer, resulting in washed-out solid fields and poor image contrast. Paper surface gloss variations distort density readings, requiring polarization filter adjustments on densitometers.