Indented Impressions of Handwriting

ESDA (Electrostatic Document Apparatus) has been the standard technique for developing impressions of handwriting for the past twenty years.

The ESDA process can:

• Produce a permanent trace of any impressions present
• Produce good results with very faint impressions
• Produce results with old impressions
• In some circumstances enable the sequence of ink writings and impressions on a sheet to be established.
  

The ESDA process will not:

• Produce good results with very deep impressions (we have other techniques to deal with such impressions)
  
• Produce results from documents which have been treated with a liquid e.g. documents that have been treated to develop fingerprints
  
• Produce good results from documents that have been in contact with certain plastics particularly file sleeves
  
• Produce good results from very poor quality papers or smooth surfaces such as magazine covers.

Documents which are to be examined for the presence of indented impressions of handwriting should be:

• Handled as little as possible - ESDA is affected by fresh fingerprints
• Packaged in paper envelopes or preferably cardboard boxes
• Protected from solvents and liquids
• Protected from the addition of extra impressions e.g. they should be placed in envelopes after the address or identifying mark has been written out.
  

Although the ESDA test is fairly simple to perform much practice is required to get the best results. The interpretation of the ESDA trace is not always straightforward and is a job best left to the experienced Document Examiner.