page_title: Holography
section_title: Holograms vs. photographs
hierarchical_section_title: Holography / Holograms vs. photographs
caption_attribution_description: English: A transmission hologram which was recorded on photographic emulsion
context_page_description: Holography is a way of making three-dimensional picture made with a laser. It allows the holographer to make a more exact image than with photography. The holograph seems to move and change slightly to look as if it were three-dimensional. Holography uses the wave aspect of light.
context_section_description: Holograms can be compared to photos. Holography records both the intensity of light, like photography, but also records the difference in the phase of light. Holography records all of information from the light that the object reflects.
  A hologram records (writes down) the light that comes from many places, so a person looking at it can see it from many angles.
  A photo can be made with normal light, like light from the sun or a lightbulb, but holograms can only be made with lasers.
  A hologram needs a second laser (the reference beam) to go onto the plate or screen where the hologram is being made.
  When a photo is cut in half, each piece shows half of the photo. When a hologram is cut in half, the entire holograph is shown in each piece. This is because each piece of a photo shows only that part of the photo, but each point on a hologram shows light from all over.
  Close up, holographs look like a random bunch of bumps.
caption: Close-up photograph of a hologram's surface. This is a hologram of a toy car.
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