Fuming Cabinet

Suspend the items to be treated in a cabinet at the upper portion. Place the iodine crystals in a clean evaporating dish inside the cabinet. Close the door

Figure 5.35 Pink fluorescent powder results on nonporous object utilizing an alternate light source.

to the cabinet. The crystals are then heated within the cabinet. Keep the items in the cabinet under observation to monitor the development of latent prints. When maximum contrast has been achieved, remove the remaining crystals from the cabinet. Then remove the items from the cabinet and, as soon as possible, photograph the prints on the item.

Ninhydrin Method

Ninhydrin is a solution that may be applied by using a spray, swabbing, or dipping method. Ninhydrin may be commercially purchased or can be prepared by the investigator. Ninhydrin reacts with the amino acids, peptides, and protein contained in the print. This chemical is used on items such as paper, cardboard, and unfinished wood. The reaction of the chemical produces what has been termed Ruhemann’s Purple. This is a pinkish/purple color print that appears on the item revealing the presence of fingerprints. The processing of an item with this method should be completed in a controlled laboratory setting. Appropriate breathing apparatus and proper ventilation should be utilized as well as thick rubber gloves. This chemical should not be inhaled, nor should the chemical be allowed to contact the skin. The preferred method of application of this chemical is by dipping or swabbing. This alleviates the possibility of accidental inhalation. To enhance or provide optimal development of ninhydrin prints, the item should be placed in a chamber where the temperature and

Figure 5.36 Latent tape on results for lifting purposes.

humidity are sufficient. The desired temperature is approximately 80°F, with a humidity rate of approximately 80 percent. For quicker results utilizing a warm iron will help. However, be sure to place clean white paper above and below the item to prevent contamination of the item.