Charred Document
Definition
Paper that has been burned to the carbonised stage but not fully reduced to ash; the cellulose has pyrolysed and the sheet is blackened, brittle and fragile but still carries the ink trace.
- State
- Burned to carbonised stage, not fully ashed
- Chemical change
- Cellulose pyrolysed
- Physical state
- Blackened, brittle, fragile
- Recoverable content
- Ink trace often still present
Common questions
Why is a charred document still forensically useful despite the damage?+
Because the sheet is carbonised rather than reduced to ash, its physical structure and the contrast between ink and paper can survive, allowing techniques such as infrared or oblique lighting to reveal writing that is no longer visible to the naked eye.
What is the main handling risk with a charred document?+
Its extreme brittleness means ordinary handling, unfolding, or even airflow can cause the sheet to fracture or crumble, so examiners typically stabilise and photograph it in place before any physical manipulation is attempted.
Related terms
- 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...
- Secondary Writing
- Term for indented impressions: writing recovered from a sheet beneath the original, also called secondary or transferred writing.
- 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,...