Secondary Writing
Definition
Term for indented impressions: writing recovered from a sheet beneath the original, also called secondary or transferred writing.
- Field
- Questioned document examination
- Also called
- Indented or transferred writing
- Recovered from
- Sheet beneath the original
- Technique
- ESDA or oblique raking light
Common questions
How is secondary writing physically recovered from a document?+
Techniques such as electrostatic detection apparatus (ESDA) or raking oblique light reveal faint impressions left in the paper fibres by the pressure of writing on a sheet originally sitting above it.
Why is secondary writing considered valuable evidence?+
Indented impressions can preserve the content of a document written on a pad and later removed or destroyed, sometimes recovering text the writer intended to conceal or that no longer exists in original form.
Can secondary writing be forged or planted?+
Genuine indentations are difficult to fabricate convincingly because they result from natural pressure transfer through multiple sheets, so examiners check consistency of depth, sequence, and writing characteristics to rule out staged impressions.
Related terms
- Charred Document
- Paper that has been burned to the carbonised stage but not fully reduced to ash; the cellulose has pyrolysed and the sheet...
- ESDA
- Electrostatic Detection Apparatus; detects latent indentations in paper by charging the surface and cascading toner particles, revealing tracing stylus pressure and writing...
- Glycerin Chamber
- Sealed humidification chamber held at 60 to 80 percent relative humidity using glycerin-water solutions to restore flexibility to charred or brittle paper...
- Indentation
- Latent pressure impression left on a lower sheet of paper when writing on an upper sheet; depth depends on pen pressure, paper...
- Oblique Light
- Side lighting at a low angle (5 to 15 degrees from the paper plane) that throws indentation shadows. The simplest indented-writing technique,...
- PVA Spray
- Polyvinyl-acetate solution sprayed in a fine mist to consolidate the surface of a charred sheet so it can be handled, mounted and...
- Steganography
- Concealing one file inside another in a way that hides the existence of the hidden file. LSB image manipulation, JPEG DCT coefficient...
- Sympathetic Ink
- Older name for invisible ink; the writing develops (becomes 'sympathetic') only after a heat, chemical or UV stimulus is applied.
- VSC
- Video Spectral Comparator (Foster + Freeman VSC-8000 series). Workhorse QD instrument combining UV, visible and IR sources with IR-sensitive cameras for ink,...