Sizing
Definition
Chemicals applied to paper during manufacture to control ink absorption and surface hardness; mechanical erasure removes sizing from the affected area, allowing rewritten ink to feather along disrupted fibres.
- Sizing types
- Internal (rosin, AKD, ASA) or surface (starch, gelatin)
- Function
- Controls ink spread and paper wet strength
- Erasure effect
- Local sizing loss increases ink absorption in that spot
- Detection cue
- Ink feathers or blurs where sizing is disrupted
Common questions
How do examiners detect sizing loss from an erasure?+
They compare ink line edges under magnification or oblique light. Rewritten ink over erased sizing feathers along disrupted fibres, while ink on undisturbed paper stays crisp and contained.
Can sizing damage be seen without magnification?+
Sometimes a dull, fibrous patch is visible under raking light with the naked eye, but confirming sizing disruption reliably needs a stereo microscope and often oblique or transmitted lighting.
Related terms
- Chemical Erasure
- Destruction of an ink's chromophore by oxidising or reducing agents (bleach, permanganate, borohydride) without physically removing paper fibres, leaving altered UV fluorescence...
- Chromophore
- The molecular subunit responsible for a dye's colour, typically a conjugated double-bond system; chemical erasure destroys the chromophore while leaving the decolourised...
- Interlineation
- Text inserted between existing lines of a document after its original execution; may be detected by ink composition differences, spatial anomalies in...
- Mechanical Erasure
- Physical removal of ink by abrasion (eraser) or shearing (blade), leaving disrupted paper fibres, altered surface texture, and residual ink in fibre...
- Nine-Point Opinion Scale
- The standard framework used by the ASQDE and most international document-examination organisations for expressing conclusions, ranging from identification through elimination with intermediate...
- Obliteration
- Covering of existing writing with an opaque layer (ink, correction fluid, or correction tape) so that the underlying text is invisible in...
- Page Substitution
- Replacement of one or more pages in a multi-page document with forgeries, detectable through paper batch inconsistencies (UV fluorescence, watermark), printing differences,...
- SWGDOC
- The Scientific Working Group for Forensic Document Examination (US), which publishes standards for typewriter examination, handwriting comparison, ink analysis, and related forensic...
- Titanium Dioxide (TiO2)
- The white pigment in most correction fluids worldwide; opaque in visible light but largely transparent above ~800 nm near-IR, making IR transmission...