ESDA® works by creating an electrostatic image of indented writing, which is then visualized by the application of charge sensitive toners. The sensitive imaging process reacts to sites of microscopic damages to fibers at the surface of a document, which have been created by abrasive interaction with overlying surfaces during the act of handwriting.

ESDA®2 features:

  • Creation of  permanent records
  • Repeatable without loss of information
  • Effective on old documents
  • A3-sized document bed
  • Original cascade development method
  • Improved toner pad development
  • Optional aerosol hood for ‘powder cloud’ development
  • Replaceable vacuum bed


ESDA® is the ideal forensic tool. As well as being simple to operate, it produces positive, life-size transparencies of indented writing without damage or contamination to original documents and without interference to other forensic tests, and documents may be processed repeatedly without loss of sensitivity.

The ESDA®2 provides the operator with three methods of development: 

  • The Cascade Developer
    This is the standard image development system for ESDA® and consists of carrier beads coated with specially formulated toner powder that becomes triboelectrically charged when in contact with the beads.
    When ‘cascaded’ over the electrostatic image of the document the charged toner becomes dislodged and is attracted to the areas of indented writing. The beads are recovered from the collection tray on the side of the instrument for reuse.
    The loose toner which may fall on to the background is recaptured by the carrier beads and removed to maintain a good image contrast.
  • The Toner Pad Development System
    Traditionally, cascade developers have been used in the image development process but ESDA®2 is supplied with a new system – the Toner Pad – a technique that ensures a cleaner operating experience 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 present. Each handheld pad has an integral reservoir of toner, sufficient for 200 images, which is simply dispensed into the pad, prior to use, with a light tap.
    The new system is cleaner to use; it removes the need to handle loose powder and, as the concentration of toner in the pad is easy to control, it eliminates problems associated with under-or over-toned cascade developer.
    The Toner Pad gives the operator better control of the image development process as it can be applied to specific areas of interest. It also eliminates the need to constantly recover cascade beads.
  • The Aerosol Hood Development System
    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.