Solvent-Loss Method
Definition
An ink dating approach that measures the residual concentration of semi-volatile solvents (particularly phenoxyethanol in ballpoint inks) relative to a non-volatile reference; the ratio decreases with age as solvent evaporates or migrates into the paper fibre network.
- Target compound
- Phenoxyethanol, a semi-volatile solvent in ballpoint inks
- Basis
- Ratio to a non-volatile reference decreases as solvent migrates into paper fibres
- Output
- Estimate of ink age
- Field
- Ink dating alongside paper and watermark examination
Common questions
How does this method relate to solvent-loss dating described for other ink analyses?+
It is the same underlying chemistry, phenoxyethanol depletion relative to a stable reference, applied here within a broader ink dating and paper examination workflow that also considers fibre composition, watermarks and optical brighteners as corroborating evidence.
Why is a non-volatile reference compound necessary in the measurement?+
Ink volume deposited on paper varies with pen pressure and stroke width, so normalising the volatile solvent signal against a stable, non-volatile ink component corrects for that variation and lets the ratio reflect solvent loss rather than differences in how much ink was applied.
Related terms
- Aging Index (Aginsky)
- The ratio of phenoxyethanol concentration in an unheated (cold) extract to its concentration in a heated extract from the same ink stroke;...
- ASTM E2494
- ASTM International's Standard Guide for Using Ink Examination Methods in Questioned Document Investigations; sets out the recommended tiered analytical approach, uncertainty reporting...
- Dye-Decay Dating (LaPorte Method)
- An ink dating method that uses HPLC-PDA to monitor the relative concentrations of specific dye components and their degradation products; the ratio...
- Machine Direction (MD)
- The direction parallel to paper travel through the papermaking machine; cellulose fibres preferentially align in this direction, making machine-made paper stronger and...
- Optical Brightening Agent (OBA)
- A fluorescent compound added to paper pulp or coatings that absorbs UV-A radiation and re-emits it as visible blue light, making paper...
- Plateau Effect
- The upper age limit of ink solvent-loss methods (approximately 5-7 years in most storage conditions), beyond which phenoxyethanol has been substantially lost...
- Rag Paper
- Paper made from cotton or linen rags, yielding long, low-lignin cellulose fibres; the dominant writing-paper substrate before approximately 1870 and still used...
- Terminus Post Quem
- Latin for 'limit after which'; in document dating, the earliest possible date for a document, established when a material component (paper, ink,...
- Watermark
- A pattern formed in paper during manufacture by localised fibre-density variation on the Fourdrinier wire; visible in transmitted light as a lighter...