Analysis of information sources in references of the Wikipedia article "Electrostatic detection device" in English language version.
Foster and Morantz attributed the ESDA image of indented writing to a change in capacitance of the Mylar-paper-platen structure (2). This change in capacitance was theoretically due to the compression of the paper.
In contrast with Seward's findings, a period of charge decay before image development is not required when operating in this optimal regime.
Experiments have been performed which show conclusively that, under certain conditions, 'impressions' of writing can be detected by ESDA (ElectroStatic Detection Apparatus) on paper which has been placed in contact with the reverse of paper bearing writing which has significantly embossed the back. Such indirect 'secondary' impressions are caused by some degree of lateral relative motion of the two sheets of paper.
However, we have further shown that relative humidity alone is not the primary determinant of the quality of ESDA results; at high levels of relative humidity and low temperatures there is a significant reduction in the quality of results and at very low relative humidity and high temperatures acceptable results can be obtained. These data strongly suggest that it is the absolute humidity of the atmosphere used that determines the quality of the ESDA results.
Fingerprinting using ninhydrin and other solvents inhibits the development of indentations
In contrast with Seward's findings, a period of charge decay before image development is not required when operating in this optimal regime.
