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How to Make
Transmission Holograms
By
Alec Jeong and Dr. T. H. Jeong
Copyright © 2005 Integraf LLC. All rights
reserved.
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1. INTRODUCTION
Transmission holograms are actually quite easy to make and
have unique features
that can truly dazzle any student, teacher, or viewer.
Making transmission holograms requires the same materials as those needed
for making a reflection hologram. In fact, many of the methods and processes
for making transmission holograms are also exactly the same as those for
making reflection holograms. The only real difference lies in how you
position the materials on your work table.
If
you have not already done so, we recommend you familiarize yourself with the
basics of making reflection holograms prior attempting to make transmission
hologram. Simply read our short article “Simple
Holography” or download our
step-by-step instructions. These articles will give you some background
on the materials involved, basic preparation, how to choose the subject,
steps for exposure and development, etc.
All
the essential materials for making transmission holograms can be
conveniently found in
Integraf’s HOLOKIT hologram kits, or purchased separately.
2. TRANSMISSION HOLOGRAMS
Transmission holograms constitute one of the two major types of holograms, the
other being reflection holograms.
All other holograms (rainbow holograms, computer generated holograms,
multi-channel holograms, computer-generated holograms, etc.) are actually
hybrids of these two types of holograms.
The
typical transmission hologram is viewed with laser light, usually of the same
type used to make the recording. This light is directed from behind the
hologram and the image is transmitted to the observer’s side. The virtual
image can be very sharp and deep. For example, through a small hologram, a
full-size room with people in it can be seen as if the hologram were a window.
Of course, making holograms of people requires a more powerful laser and
significant safety precautions, but you get the idea. Transmission holograms
are like a window to another world. Remember Alice in Lewis Carroll's
Through The Looking Glass?
Unique Features of Transmission Holograms
There
are some unique features of transmission holograms that"wow" the viewer:
-
Captures an image of a subject much bigger than the holographic plate or
film sheet that records the hologram. Reflection holograms cannot do this
easily.
-
Have an image can be projected onto a screen or other surface with a laser.
-
Can be broken into small pieces whereby each piece still contains the entire
image. Yes, that's right. If you were to smash a hologram with a hammer and
then shine a laser
through just one piece, the entire image can be still be projected and
viewed.
-
Can record more than one image on the same holographic plate of film sheet;
in effect, adding a “channel” for subsequent images. When viewing the
finished hologram, you can “tune” to different channels by rotating the
hologram and see your different images!
Drawbacks of Transmission Holograms
Notwithstanding the unique features above, transmission holograms are usually
not the first hologram of choice for artists, hobbyists, and first-time
holographers. The main reason for this is due the fact that transmission
holograms must generally be viewed with laser light instead of white light.
Practically speaking, this makes transmission holograms less convenient
than reflection holograms to display.
2.
EQUIPMENT AND MATERIALS
FOR MAKING TRANSMISSION HOLOGRAMS
To
make transmission holograms, you use the same equipment and materials you
use for making reflection holograms, as explained in “Simple Holography”.
Essentials
|
Material |
Notes |
|
Holographic Plates (or Film) |
PFG-03M and PFG-01
emulsions both make excellent holograms, but PFG-01 is especially good for
transmission holograms. |
|
Diode Laser for Holography |
Red sensitive (650nm)
3mW to 5mW (Class IIIa)
Removable collimating
lens
Stabilized power and
frequency
Coherence length of
approximately 1 meter |
|
Clothespin |
To hold the laser |
|
Chemical developer & bleach |
Use JD-2 or JD-3 kits
(with PFG-01)
Use JD-4 kit (with
PFG-03M) |
|
Five developer trays |
Three small ones, and
two large ones |
|
Photoflo solution |
To help avoid smudges on the finished
hologram |
The
above materials can all be found in the
hologram kit or catalog provided by
Integraf. While the HOLOKITS come standard with PFG-03M, you can request to
substitute this emulsion with PFG-01 (with JD-2 developer).
Other
accessories generally recommended are
a computer mouse pad, a
cup of sand (salt or sugar will also work), a hardcover book (or piece of
cardboard) to serve as a shutter, coins (or other appropriate object as the
subject for your hologram), distilled water, and a hair dryer
(optional). Again, please see
"Simple
Holography" or the downloadable
step-by-step
instructions to understand how these items are used.
Now,
your ready to
set up to
make transmission holograms . . ..
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