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Introduction

Vibrations

Processing

SB Transmission

Exposure

Recording

SB Reflection

MB Transmission

MB Reflection

Lighting

Resources

Lighting Techniques

I produce white light reflection display holograms because the images are monochromatic (gold in color), lend themselves to a more realistic representation of the original object or scene, and do not need a laser to view them. Because of the diffractive nature of holograms (each atom in the object scene recorded in the emulsion acts as a diffraction lens), keeping the image close to the plate plane enhances the image's monochromatic effect (single color reconstruction) and resolution (sharpness). As the image is moved away from the plane of H2, factors come into play that decrease monochromaticity and resolution. This can cause the image to no longer be gold in color and start showing multiple rainbow colors. These multiple colors are actually multiple colored images of the object scene being created as the white light starts to spread into a rainbow the further the reconstructing light moves past the plate. The actual term for this phenomenon is called white light dispersion.

My normal method of illuminating display reflection holograms is by hanging the hologram on a wall and using track lighting on the ceiling to illuminate the hologram (overhead lighting or overhead reconstruction) as shown in Figure 90. Figure 86 would be the appropriate optical setup for this. Figure 89 would be the appropriate optical setup to illuminate the hologram with the light source on a desktop (underneath lighting or underneath reconstruction) as shown in Figure 91. The reconstructing angle for both types will be the recording angle which is 56 degrees.

white light reconstruction overhead image
    Figure 90: Lighting arrangement showing
  ceiling illumination (Figure 86 optical setup).

white light reconstruction underneath image
    Figure 91: Lighting arrangement showing
desktop illumination (Figure 89 optical setup).

In the following two photographs, both the skull and the human brain are projected 3 inches out in front of the plate. You'll notice that you can project fairly far out in front of the plate without getting any dispersion.

8 x 10 white light hologram of human skull image
Figure 92: Close-up of an 8" x 10" hologram
                    of a real human skull.

8 x 10 white light hologram of human brain image
      Figure 93: Close-up of an 8" x 10" hologram of a
                sagittal section of a real human brain.

I use Halo or Hampton Bay brand halogen lamps. Specifically, I use the L2710 MBX lamp holder or equivalent for overhead track lighting as shown in Figure 90. For desktop illumination, I use the Halo Fixture Fitting L1974 to hold the lamp as shown in Figure 91. The lamps that plug into the holder should be at least 50 watts to 65 watts and have a narrow beam designation [ (Sylvania brand 65MR16Q/NSP(FPA) ]. All lamps should have a clear, glass envelope, not frosted.