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Calcimator

Paper Opacity Calculator

Estimate paper opacity from basis weight, filler content, TiO2 loading, fiber type, and calendering. Uses Kubelka-Munk scattering theory.

Inputs

%
%

Results

Printing opacity (%)

99.75

TAPPI opacity (%)96.76
Scattering coeff (m²/kg)75
Show-through risk0
Total filler (%)15
How to Use This Calculator
  1. Enter the paper basis weight (GSM) for the grade being evaluated.
  2. Input total filler (%) and TiO2 percentage of that filler from your formulation.
  3. Select fiber type (chemical kraft, mechanical, or blend).
  4. Choose calendering level (0 = none to 3 = heavy supercalender).
  5. Review Printing Opacity (%), TAPPI Opacity, Scattering Coefficient, and Show-Through Risk.

How the result changes with Basis weight (GSM)

Basis weight (GSM)Printing opacity (%)
5998.8
182100
329100
451100

What each input means

Basis weight (GSM)
Paper grammage in grams per square meter.
Total filler (%)
Total mineral filler loading as percentage of sheet weight (includes TiO2).
TiO2 in filler (%)
Titanium dioxide portion of filler. TiO2 has very high light-scattering power.
Fiber type
0 = Chemical (kraft), 1 = Mechanical (groundwood), 2 = Blend.
Calendering level
0 = None, 1 = Light, 2 = Moderate, 3 = Heavy supercalendered.

What each result means

Printing opacity (%)
Estimated printing opacity percentage (0-100).
TAPPI opacity (%)
TAPPI T 425 contrast ratio opacity estimate.
Scattering coeff (m²/kg)
Total light scattering coefficient.
Show-through risk
Print show-through risk: 0 = None, 1 = Low, 2 = Moderate, 3 = High.
Total filler (%)
Confirmed total filler loading percentage.

How this is calculated

Worked example, using the default values

  1. Identify Input Parameters
    4 parameters
    Basis weight (GSM) = 80, Total filler (%) = 15, TiO2 in filler (%) = 0, Fiber type = 0 = 5 input(s) provided
  2. Calculate Printing opacity
    Printing opacity = opacityFraction * 100
    99.75 = 99.75
  3. Calculate TAPPI opacity
    TAPPI opacity = min(100, opacityPct * 0.97)
    96.76 = 96.76
  4. Calculate Scattering coeff
    75 = 75

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