foster + freeman

Description

ESDA is the leading technology for detecting indented writing on questioned documents. ESDA works by creating an invisible electrostatic image of indented writing, which is then visualised by the application of charge sensitive toners. The sensitive imaging process reacts to sites of microscopic damage to fibres at the surface of a document, which have been created by abrasive interaction with overlying surfaces during the act of handwriting.

• more sensitive than oblique lighting
• simple to operate
• produces permanent 1 to 1 transparencies
• responds only to indented writing - ignores visible script
• non-destructive - leaves documents uncontaminated

Features

A new image development system

Traditionally, cascade developers have been used in the image development process but ESDA² is supplied with a new system - the Toner Pad – a technique that ensures a cleaner operation while maintaining excellent sensitivity. A soft, brushed-textile pad, impregnated with toner is simply wiped across the surface of the imaging film to produce visible images of any indented writing. The new system is cleaner to use, removes the need to handle loose powder and eliminates the problems associated with under-or over-toned images. ESDA² retains the standard cascade developer, however, for those who prefer the traditional method of image development.

New A3 vacuum bed with filter system

The larger, removable vacuum bed and wider imaging film enable documents up to 310mm × 440mm to be processed.  ESDA² also features a powerful extraction fan and filter to remove any airborne toner particles and ozone.

A new large capacity document humidifier is also provided to optimally pre-condition  the documents prior to the ESDA² electrostatic imaging process.

Images of indented writing can be made permanent by the simple process of laminating the developed images with the  transparent self-adhesive fixing film.

ESDA²  is supplied with one reel of imaging film, cascade developer, 50 toner pads, a pack of fixing film and a document humidifier.

Aerosol Hood development system (optional accessory)

Now available as an accessory, the Aerosol Hood is an alternative to Cascade Developer and the Toner Pad. It dispenses a fine powder cloud of toner which is attracted to the electrostatic image of any indented writing as it settles over the document. The clear acrylic hood enables the operator to monitor image development to obtain optimum results. It uses the same toner as the cascade developer.

 

Applications

An example application of the ESDA process