Transmission holograms are viewed with the light source on the opposite side of the hologram from the viewer, so that the light is transmitted through the hologram. They are viewed with laser light, since white light gives a rainbow "smear."
Reflection holograms are viewed with the light source on the same side as the viewer; the light is reflected off the hologram.
Transfer holograms are made by using a holographic image from a "master" hologram as the object of a second hologram. By using this technique, the object can appear to be behind, in front of, or straddling the plane of the hologram.
Rainbow holograms are transfer transmission holograms where the original "master" hologram has been masked off through a horizontal slit. This reduces the vertical parallax, but enables the hologram to be viewed by white light without causing a rainbow smear. The object appears to change colour as the viewpoint moves vertically.
Multiplex (or Cross) holograms are stereoscopic holograms made by taking a series of photos with the camera tracking past a subject. This series of photos is then transferred to a hologram through vertical slits. The viewer sees a series of stereo pairs as he moves across the hologram.
Animated holograms are made in a similar way but using time-lapse photography, allowing the subject to move between exposures. When the hologram is made from these photos, the subject appears to move as the viewpoint changes.
Pseudo-colour holograms can be made by pre-swelling the photographic emulsion before making the exposure. The amount of pre-swelling determines the colour of the image. By making two or more different exposures with different amounts of pre-swelling, different parts of the image can be recreated in different colours.
Embossed holograms, such as are seen on credit cards, are made by a manufacturing process which uses a metal replica of a master hologram, which can then be used to print the relief pattern onto plastic.