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Monday, 24 August 2009

Lifting Fingerprints~

Super Glue Fuming~

Although it may sound odd, the fume of superglue is one of the three basic things used to find fingerprints. Research proves that the fumes of superglue in a small closed environment, with the object that has the invisible prints, will not only show one the outline of the fingerprint, but it will also clearly show the print, leading the police closer to the criminal. The fumes from the super glue, or Cyanocrylate Ester, helps find prints on many different smooth surfaces including glass or plastic.

Powder~

Powder is usually used when fingerprints are visible, bought are not clear. The color of the powder must always contrast with the surface color. For example, a black table usually calls for the use of Talcum Powder, which is white. Or, on glass surfaces Carbon powder, which is black is most likely used. After the powder has been sprinkled onto the print, the excess powder is brushed away and a piece of tape is placed on the print and lifted, capturing the design of the print. There are also dyed powders that can also be used, depending on the color of the dry, nonabsorbent surface. Furthermore, there are also fluorescent powders, which are a fine powder, used to detect prints with low UV rays.

Chemical~

Although using chemicals to visualize fingerprints is highly effective, it is usually only done in labs. One of the chemicals used is iodine, and just as superglue, it is the fume used which discovers the print. Iodine is a solid crystal that when heated, skips the liquid phase and immediately becomes a vapor, called sublimation. This vapor then combines with the print allowing it to become visible. The only downfall is once the process is complete, the print becomes invisible once more; therefore, during the process, a picture of the print is usually taken or starch is sprayed onto the surface leaving the print visible for months.

Information:
http://www.csigizmos.com/products/latentdevelopment/processing.html

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