Visualising indented writing or embossing

Both the VSC5000 and VSC4^PLUS feature orthoganol oblique lighting, illumination from two light sources at different angles, that provide the examiner with a clearer image of indented writing or embossed stamps.

However, not all such examinations are straightforward, as the presence of printing or handwriting on the document may interfere with the image and hinder examination. When the ink causing interference is transparent to near infrared light, it can be eliminated by conducting the examination at this wavelength. After the VSC5000 converts the infrared image to a visible one the ink will appear to vanish while the infrared shadow remains. Both the VSC5000 and the VSC4^PLUS enable such examinations to be made at wavelengths in the near infra red up to 1000nm.

Although the shadow casting technique is useful for examining deep indentations and embossing, shallow indentations or those not visible at all, are more effectively examined using an electrostatic imaging technique.

See details of the company's product ESDA².

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