Forensic Dentistry, Second Edition

224 Forensic dentistry

unpredictable and vary to a great degree in intensity and quality. Second, the

exact amount of focal shift to produce a sharp photograph must be determined.

With viewing screens on the newer digital cameras designed specifically for

nonvisible imaging, focal shift can be determined long before the image is

acquired^36 (Figure 11.27). Developing confidence and getting predictable

70 Kodak 18-A UV Pass

60

50

40

%T

30

20

10

0

0 200 400 600 800

Wavelength (nm)

1000 1200 1400 1600

Figure 11.23 the transmission curve of the Kodak wratten 18-a uv filter. note
the small peak in the ir range of light that contaminates the uv image, prevent-
ing this filter from being used (by itself) for digital uv photography. (source:
http://www.beyondvisible.com/Bv3-filter.html.))

100

90

80

70

60

%T^50

40

30

20

10

0

300

Baader Venus 1.25" UV Transmission Fi lter

(o nly 0.15% IR leakage at 737 nm, 0.3% at 813 nm and 0.1% at 872 nm)

Baader U

400 500 600 700 800 900 100 110 120 130 140 150

000000

nm

Figure 11.24 the transmission curve of the Baader venus uv filter. notice
that predominantly uv light is able to pass through this filter with negligible ir
transmission spikes.