Document Age Estimation Calculator

Estimate document age from ink volatile analysis and paper acidity. Uses exponential decay modeling of ink solvent evaporation.

Inputs

Ink Volatiles Remaining

Paper pH

Reference Sample Age

yrs

Tab to move between fields

Results

Estimated Age

5.5 years

Confidence Range

3.9 – 7.2 years

Degradation Rate (k)0.15

How to Use This Calculator

Enter Ink Volatiles Remaining, Paper pH, and Reference Sample Age.
Review Estimated Age (years) and Confidence Range.
Use Degradation Rate (k) to inform your decision.
Use the chart to visualize the results and explore different scenarios by adjusting inputs.

How the result changes with Reference Sample Age

Reference Sample Age	Estimated Age	Confidence Range
5.45	6.1 years	4.3 – 7.9 years
18	19.8 years	13.9 – 25.7 years
33	36.3 years	25.4 – 47.2 years
45	49.5 years	34.7 – 64.4 years

What each input means

Ink Volatiles Remaining: Percentage of volatile solvents remaining in the ink (measured via GC-MS).
Paper pH: Paper acidity (pH < 7 is acidic). Acidic paper degrades faster, aging the document.
Reference Sample Age: Known age of a reference ink sample for calibration.

What each result means

Estimated Age: Estimated document age adjusted for paper acidity.
Confidence Range: Age range accounting for analytical uncertainty.
Degradation Rate (k): Exponential decay constant for the ink system.

How this is calculated

Worked example, using the default values

Identify Input Parameters
Ink Volatiles Remaining = 40, Paper pH = 6, Reference Sample Age = 5 = 3 input(s) provided
Calculate Estimated Age
5.5 = 5.5
Calculate Confidence Range
Confidence Range
3.9 – 7.2 years = 3.9 – 7.2 years

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