SMJE 1032
Introduction To Electronic
System Engineering
Oral Presentation
Holography
Nur Syamimi Bt Mohd Jafri
Nurul Waahida Bt Mohd Shah
Tew Yan Fen
Introduction
HOLOGRAM
Hologram is a three dimensional imaging technique. It uses laser light to record
the pattern of light waves reflected from an object onto the emulsion of light sensitive
film (or glass plates). When that film is developed and re-exposed to laser light (or
normal incandescent light like most holograms today), it recreates in space all the point
of light that originally came from the object. The resulting image, either behind or in
front of the holographic film , has all the dimension of the original object and looks so
real that you are tempted to reach out and touch it. There are two types of holograms
which is reflection and transmission. They can distinguished by the way in which they
are illuminated. Reflection holograms are light from the front, reflecting the light to you
as you view it, like painting or photograph hung on the wall. Different film emulsion
produce images with different characteristics. Silver halide is the emulsion of choice for
most artist and holographers who use silver halide glass plates to achieve the higher
quality images. Holographer use silver halide film which is cheaper, less fragile and
easier to handle but does not produce the depth, resolution and projection possible with
glass plates. However, film is used successfully for longer production runs. Besides that,
dichromated gelatin(DCG) is a chemical gelatin mix that is coated onto a piece of glass.
Dichromates produce very bright images in a golden yellow color. The images have the
least range of depth, but they are viewable in normal light without special spotlights. This
makes dichromates suitable as small gift products for consumer gift market or the
premium and incentive industry. Photo polymer is the newest of the recording materials.
Photo polymers have a plastic backing and are suitable for long production runs. The
image depth of polymer is slightly less than that of silver halide, however the images are
brighter with a wider angle of view. In addition, transmission holograms are light from
the rear (like a photographic transparency) and bend light as it passes through hologram
to your eyes to form the image. Laser transmission holograms are made with lasers, like
all holograms but also must be light with laser to be viewed. Therefore the image appear
in color of the laser used in illuminating them for viewing usually red(helium neon laser)
. Other types of holograms use a laser transmission hologram as the master, from which
copies are made. White light transmission are illuminated with incandescent light (white
light) and produce images that contain the rainbow spectrum of color. The colors change
as the viewer moves up and down and are often called rainbow holograms.
Methodology
In making transmission holograms, some materials have to be prepared. Those are
holographic plates or film, diode laser for holography, clothespin, chemical developer
and bleach, five developer trays, and photoflo solution. Holographic plates or film are
used to record the holograms. Diode laser is used to fully illuminate the object. Next,
clothespin functions to hold the laser while chemical developer and bleach are for the
developing process of the holographic plates. Five developer trays which three are small
and two are large in sizes are also needed for the developing process. Photoflo solution
helps to avoid smudges on the finished hologram. It is a wetting agent that helps
holograms turn out cleaner and clearer. It also reduces streaks and promotes more
uniform and quicker drying. Although Photoflo solution is actually not required to make
a hologram, it does help them look better.
The methods used to produce transmission holograms are much similar to the
steps used for reflective holograms. First, the diode laser is adjusted in its holder so that
the beam spreads out horizontally. The chosen object is placed at a distance of 35 to 40
cm from the laser. Then, a white card is placed behind the object and the laser is adjusted
while looking at the shadow on the card. The position of the laser is adjusted until the
object is optimally illuminated. After that, the white card is removed. Next step is that an
opaque cardboard is placed near the laser to block the light from reaching the object. This
will serve like the shutter of a camera. Another step, a holographic plate is removed from
its container in the darkest part of the room and close it back. The holographic plate is
leaned on the object, making certain it will not slip or move; the emulsion should touch
the object. Time for the object to settle is about 10 second which means the room has to
be hold still. After that, the cardboard is lifted slightly off the table while still blocking
the laser light, and wait 2 seconds for the vibration to subside. The cardboard is then
lifted all the way up to expose the holographic plate and object for 10 seconds and the
light is blocked again soon after that. Lastly, the exposed holographic plate is processed
by using the chemical developer and bleach such as JD-4. Optionally, the holographic
plate can be placed in the Photoflo solution for 20 to 30 seconds.
After the drying process is completed, the hologram can be viewed with a point source of
incandescent light such as the light from projector, flashlight of the sun. Diffused light
sources such as frosted bulbs and florescent lamps cannot be used to view the hologram.
For the best results, the emulsion side can be sprayed paint with a diffuse black paint to
protect the emulsion and provides a dark background to enhance the visibility of the
image.
Application
Security and product authentication
As a security devise, holograms are widely used on tax stamps of many countries. Tax
stamps are issued by governments principally on alcohol and tobacco to ensure duty is
paid and to distinguish genuine products from fakes. There are two varieties of
holographic tax stamp—hologram tax stamp with security paper and only hologram with
or without serial no. Hologram use to indicate the authenticity of certain product. The
presence of hologram becomes a powerful obstacle to counterfeiting. Hologram usage on
documents, anti-counterfeiting, tamper-proofing, customizing ticket protection,
identification documents including credit and phone cards, drivers licenses and so on to
minimize counterfeiting.
Entertainment
Various Hollywood movies, especially the science fiction films, have used holographic to
make some special effects. Even movie posters are made holographic. Holograms are
also used as promotional tools on records and CD covers. Some of the popular movies
also using holographic effects. Like Star Treks' Holo deck, Star Wars' Princess Laya,
Hologram Man and Escape from LA.
Packaging (Consumer Goods Brand Protection)
Hologram packaging includes flexible packaging, board packaging, rigid box, pack
packaging and so on. All this type of packaging will increase the product attraction by
provide eye catching impact, authentication, added value and hence increase the product
sales. In addition, it also enhances the company’s image.
Labels and Tapes
Holograms are also used in labels, tapes and stickers. They are provided with a self-
adhesive backing. They are also provided as hot stamping foil. Label applications include
direct mail, promotional products, advertising pieces, and point purchase displays.
Medical applications
Holographic technique is also used in various medical applications like CAT scans, X-ray,
MRI, Ultrasound, ophthalmology, endoscopy, otology, orthopedics and many more.
Art and Interactive Graphics
Holography is an art in itself as it deals with making some kind of visuals. By using
holographic effects for the background of over printing lithography, some of the in-store
lighting problems of holograms can be overcome. Color printing combined with
holography form stunning interactive visual effects.
Professional Photographers
Professional photographers can also use holographic technique as add-ons or alternatives
to regular two-dimensional portrait photography products.
Optical Devices
Holographic lenses, diffraction gratings are optical devices in which the "object" is a
mirror or a lens. They can be used to perform more specialized functions like making the
panel instruments of a car visible in the windshield for increased safety. Holographic lens
system to read bar codes is widely seen in supermarket and department store scanners.