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A check containing a fingerprint impression on an Authentiprint fingerprint sticker was submitted for comparison to a known forgery suspect. The comparison was completed, and a positive identification to the suspect was established. Reports were written and a case file was created containing the original check. The check and case file were filed away.

A year after the original comparison was made, the case was being heard in court. However, the examiner who originally made the comparison was no longer working for the department. As our standard procedure, if the original examiner is not available to testify, the verifier is called upon to take the case. After the verifying examiner received a subpoena, the case file was retrieved and reviewed. At this time, it was discovered that the fingerprint on the Authentiprint sticker had completely faded. The area was completely blank.

During an alternate light source (ALS) training session, an ALS (Omnichrome 1000) had been used to visibly improve inked fingerprint impressions that were either too light, smudged, or obliterated by the background on the document. We decided to try an ALS on the faded Authentiprint fingerprint. All of the ALS’s light settings were used in combination with orange, yellow, and red barrier filters. The best fluorescing fingerprint impression was achieved at 570 nm with a red barrier filter.

Several photographs of the Authentiprint label, fingerprint, and check were taken. The photographs were taken using a 35mm Minolta X700 camera with a Minolta MD 50 mm macro lens. Kodak Professional T400CN Black & White 400 ASA film was used. The film was developed using C-41 processing (standard color film process). The camera was set up on a copystand using two daylight balanced fluorescent lights (normal light).

A photograph was taken to show the overall front portion of the check placing the exact location of the Authentiprint sticker (Figure 1a). The exposure setting for this photograph was f-8 @ 1/60 second.

Another photograph was exposed to show both the overall front portion of the check and a faint fluorescing fingerprint image on the Authentiprint sticker. It was taken by using a double-exposure technique. The first exposure was taken using the ALS set at 570 nm. The ALS light wand was placed approximately 15 inches from the check. The exposure setting was f-8 @ auto-setting. Three bracketed exposures were taken. One exposure was taken at the auto-setting; the other two were taken at one-and-one-half stops over- and under-exposed (from the auto-setting). After each exposure with the ALS, each of the bracketed photographs was re-exposed at f-16 @ 1/60 second using normal light. The best photograph was taken at one-andone-half stops underexposed (Figure 1b).

A close-up view of the blank Authentiprint sticker was taken with normal light. A Minolta 1:1 auto-extension tube was used with the macro lens (Figure 2)

A photograph was taken to show the bright fluorescing fingerprint impression on the check and the slight ghost image of the check (Figure 3). The same exposure procedures were used as with photograph 1b, except that the emphasis was placed on the ALS exposure. A very short normal light exposure was used.

A final photograph was taken to show the close-up fluorescing fingerprint impression on the Authentiprint sticker. This photograph was taken using the ALS set at 570 nm. The ALS light wand was placed approximately 10 inches from the check (exposure setting was f-8 @ auto-setting). Three bracketed exposures were taken. One exposure was taken at the auto-setting; the other two were taken at one-and-one-half stops over- and under-exposed (from the auto-setting). The best exposure was taken at one-andone-half stops over-exposed (Figure 4). This photograph was printed to produce a 1:1 image of the fluorescing Authentiprint fingerprint. The suspect’s fingerprint was recompared to the life-size image of the fluorescing Authentiprint. The examiner arrived at the same positive conclusion as previously obtained on the first comparison. During the trial, the suspect plead guilty to the charge of forgery.

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