Topic Name: Creation Of Special Effects
Category: Optical imaging
Research persons: 4engr.com
Location: NIST, 100 Bureau Drive, Stop 1070, Gaithersburg, MD 20899-1070, United States
Slides of the special effects
How to create an explosion? Which techniques are employed to put in scene
dinosaurs with men? The cinema uses many special effects to captivate the
spectators fully. The Net surfer shows you the back of the decoration.
Realization of explosions
Explosions of cars, flames spouting out of any share, not doubt you are well in
a film of action. Objective: to surprise the spectator while sticking to more
close with reality. How the bomb disposal experts proceed? Various techniques
are at their disposal.
Use of explosive truths
So that the deflagration is most credible possible, the realizers do not haggle
over the means and leave heavy artillery. The pyrotechnics, professionals of the
explosives use to reduce in crumbs cars or another decoration of studio of the
explosives known as deflagrating. There exists breaking but they are too much
dangerous to handle because their compounds are unstable. The least shock can be
transformed into drama.
The more known blasting powder to be employed formerly in the guns is an
excellent fuel and it is quite homogeneous thus stable. But how does an
explosion function? All rests on chemistry and more particularly on a reaction
of transfers of electrons .An oxidant and one reducer are put in presence and
interact. The oxidizing compounds, nitrates, chlorates or per chlorates are used
as fuel while releasing from oxygen. It will be collected by the reducers,
sulphur, carbon or magnesium called fuels. But which causes combustion? Fire,
from where the recourse to wicks. The firing can be carried out remotely year
connecting of electric wire to a central order or by detonators connected to the
same system release. Combustion generates a matter in overpressure then. While
turning over to balance with the atmospheric pressure, it creates a deflagrating
Amplification by models
For large buildings or official buildings, a model is created. Do you believe
that for the film Independence Day, realizer A really destroyed the Empire State
Building or the White House?
Generally, the model makers work out the support in plaster and plastic. The
small loads are placed on all the model, at strategic places so that the
deflagration is total. To be sure of their blow, the specialists perforate
materials following of the lines of break. Result: the model is entirely
The difficulty resides then, not in the explosives but in the film techniques.
Several cameras film the action at high speed and under various angles. Then
with the assembly or in post-production, images of the scene sontt slowed down
at a speed of 24 /second images. The explosion takes very an other dimension and
the remains circle everywhere for an incredible effect.
Smoke screen or fog
Michaël Jackson in person used of this special effect for its Thriller clip. A
means simple to generate a mysterious environment, of fear or suspense. And you
will see, to produce smoke or fog, anything simpler. It is enough to observe
nature and the turn is played.
The fog is generally formed with the top of water, often colder than the ambient
air. Photograph © COPIOUS Patrice (galleries photographs of the Net surfer)
When physics is interfered
In winter, it is common to observe with the first gleams of the day, of the fog.
From which does this phenomenon come? Physics is at the origin of this
demonstration. The fog is formed same manner as the clouds. A mass of air passes
to the top of a cold surface. The air contains water molecules in gas form. In
contact with the cold air, the temperature will fall and cause a change of state
water. The molecules will pass from a gas state to a liquid state, condensation.
Fine droplets in suspension or small crystals of ice, accompanied by microscopic
particles cantatrice of moisture, will pile up generating a thick cloud on the
level of the ground or a river, the fog.
Beyond that, an ambient temperature lower than 0° C, water still changes state
and is transformed into ice or white frost and will settle on the ground. And
well, the professionals of the special effects base themselves on this purely
physical natural phenomenon to reproduce smoke or fog with the cinema or in
“Smoke-producing” compounds naturally
There still nature offers on a plate the compounds necessary to the clothes
industry of smoke. Is enough to have some concepts of physics.
Carbon dioxide present in our atmosphere exists in gas form but also in solid
form: carbonic ice or dry ice. It is obtained by compacting dry ice, CO2 is
present in the liquid state there. Its temperature of surface east of -78° C. to
create smoke leaving for example a magic potion, the technicians plunge a
pastille of dry ice in hot water. With its contact, it starts to melt and
releases gradually from carbon dioxide, heavier than the air. Contrary to the
steam, it does not go up and goes down causing a thick smoke.
This effect can be also produced by liquid nitrogen. It is very often used in
the medical field to treat warts either to freeze embryos or ovules. This liquid
nitrogen is a gas diazotizes cooled in lower part of its point of boiling to
-195,79° C. Stored in isothermal bottles, the gas is maintained at this
temperature. While opening the bottles, the liquid nitrogen comes into contact
with the ambient air and cools it instantaneously. This fast condensation causes
a cloud made up of fine water droplets.
Creative machine of smoke
To optimize to the maximum this phenomenon and to produce smoke in large
quantity, the technicians use a smoke-producing machine. The majority of these
guns with smoke function starting from glycol or of glycerin. Inside, the fluid
made up of water and glycol/glycerin, is pumped and sent towards a heating
system. The liquid phase changes then into gas, evaporation. The volume of
produced gas generates a certain pressure in the machine which expels the cloud
at the exit. The ambient air being colder than gas, this one condenses and
creates a fog.
This process functions very well but the technicians generally use it in an open
space or then ventilated well because the glycol or oils can have effects on
else blood and wounds
The films of horror use and misuse hemoglobin at the point to nauseate the
spectators of them. Fear anything, no actor is not bled with white during
turning. A small very simple formula that you can reproduce on your premise is
concocted before each scene.
A very sweetened formula
As opposed to what one believes, it is not necessary to have a diploma of
chemistry “to cook” false blood. By preoccupations with a realism, the scenario
writers used ox blood which butcheries gave them readily. Only concern: this
blood coagulates too quickly and becomes maroon. Not practices when many catches
should be carried out. Then, the technicians created each one their secret
formula to develop their hemoglobin.
All the ingredients are easily in the trade. It is enough to mix chocolate tubes
some that one puts on the ices with carmine food dye and water. Attention should
be paid not too much not to dilute the mixture and to keep a viscous aspects
stick to more close to reality. You can easily replace the chocolate by potato
flour or flour. The important thing is to use a product which homogenizes. Small
indication: do not use toxic dyes because the mixture is in direct contact with
Techniques of dissimulation
How to reproduce cuts truer than natural or a “sticking” in rule? The
technicians redouble ingeniousness to prevent the spectator from finding
trickery. And you will see that these special effects inevitably do not require
large means nor of advanced technology.
To simulate a cut, the accessories supplier takes a traditional knife from which
it eliminates the effect slicing while passing it to the grinding machine. It is
necessary imperatively that when it passes on the skin, he does not wound the
actor. On the internal face of the blade, a hose connection filled of false
blood is fixed. At its end, a syringe is positioned to make squirt blood. And
there, the realizer enters in scene while playing with his camera and uses
various plans so that the assembly is not seen. At the time of the cut, the
scenario writer carries out a large furtive plan and at the same time, a person
presses on the syringe to make leave blood. So that all is perfect, a
synchronization is essential. Without what, the effect of surprise falls flat.
At the time of scenes of fight, the actors can hide small capsules in their
mouth and crunch them at the time to make ooze blood on the level of commissars.
As for the impacts of balls, a hecatomb is hidden under clothing and a small
load explodes it remotely.
Special effects all that there is of simpler but the plays of camera take part
largely in the desired effect.
The laser saber
Arm worship with the trilogy of George Lucas, the Star Wars, the laser saber is
a pure illusion. In reality such a tool does not exist. How the technicians
began there it to work out and m^me to improve it at the time of the last three
An impossible reality
Who forever dreamed to be caught for Luke Skywalker or Dark Vador with their
incredible “laser sword”? Everyone of course. And well unfortunately, these
weapons are only pure fiction and this for physical reasons well defined.
The laser is propagated in a direction and is invisible with the naked eye what
is not the case in film. To be able to observe the pencil of light, it is
necessary that particles interact with him. The best example is of soupoudrer
chalk and the ray appears. Another problematic case: finite of the laser. The
ray does not stop like that. It diffuses read further possible until absorption.
To obtain an effect similar to the sabers of Wars Star, would have to be applied
a reflective mirror with the end but it is all the same difficult to maintain it
in the air. Last element which definitively eliminates a possible existence from
this laser saber, the “shock” and noise produced at the time of the engagements.
The laser is a light made up of photons. In physics, the light is known as
immaterial. It is thus perfectly impossible of entrench queer two beams laser
In our Universe, the only compound able to fulfill such a function would be
plasma, a heated gas where the atoms are uncoupled from their (S) electron (S).
A faking which evolved/moved
With each turning of a new shutter of his saga, the realizer George Lucas and
his team of technicians developed various easy ways to create these famous laser
In the very first episodes, dating from the Seventies, technology was not at the
current level. To make the sabers luminous, the accessories suppliers had made
swords assembled on a motorized handle. Along the blade, three mirrors were laid
out so as to return by phenomenon of reflex ion the light projected by a spot
beside the camera. Proving not very effective, this system was abandoned with
the profit of a process of animation developed at the point by Dave and max
Fleischer in 1914, the radioscopy. It consists of the incrustation of an image
on the video already recorded. How?
Actors moment the scene of combat with simple rods all. Progressively with the
episodes, the materials used for their clothes industry evolved/moved, while
passing from aluminum to the sophisticated fiber ultra carbon. Before the
appearance of data processing, the radioscopy was done by a show of hands.
Maintaining with digitalization, this process takes much less time and the
realizer can directly incorporate sabers laser of different color without
difficulty. It is just enough to have the good software.
In the Co and Star Wars, the radioscopy was especially used for the battles
between the spaceships. Models of vessels were manufactured. The cameras filmed
them on all the sides. Then, the technicians added them on a star bottom drawn.
The images amalgamated and all appeared real.
As for the mythical noise of the laser sabers which are entrench opulent at the
time of the engagements, the sound-effects men are in the beginning. Without
them, the desired effect would not be obtained. This its private individual was
invented by Ben Burtt. How did create? It just mixed the noise of a lamp of
projector with the sound emitted by the interference created by a television on
an audio cable not armored.
Technique of the holograms
Of Trek Star while passing through Wars Star, all the films of science fiction
call upon holograms. Remember the way in which the Emperor with Dark Vador
A three-dimensional image
As opposed to what one could believe, this technique of creation of the
holograms, holography, is not of nothing recent. The first to have
included/understood the transformation of an image 2D into 3D is the Hungarian
physicist Dennis Gabor in 1948. How? It developed mathematical equations
materializing a three-dimensional photographic system. From these theoretical
principles was born the first hologram in 1965.
The holograms are photographs 3D which seem as suspended in the airs. How to
obtain this effect? It is physical quite simply. But this technique could be at
the point thanks to the appearance of a monochromic source of light, the laser.
Without it, the effect is not possible.
An object which one wishes to represent in hologram is sandwiched between the
laser and the photographic plate where will print the image. That functions like
a film. The laser emits a pencil of light which will be divided into two thanks
to semi-reflective mirrors. One of the rays illuminates the plate located in
background and the other lights the object; it is then considered on the plate.
Automatically, the two beams meet and create interferences. They then will print
the three-dimensional image of the object on this plate by taking account of the
To restore the image, the printed plate is lit by the laser under. The object
appears in 3D. Magic!
Reality or fiction?
Of course, this result is not comparable so that one observes in Retour towards
the future or Wars Star. At present to carry out such a prowess, the technicians
polish the holograms thanks to data-processing software and resort for much to
synthesized images. But soon, science fiction will not be so any more far away
from reality .
Researchers of the USC (University of Southern California) developed the very
first holographic screen in 3D which projects in the air a hologram. This device
functions thanks to a horizontal mirror turning at high speed and a projector.
But the system is still little succeeded and requires fuller research.
The Japanese of the AIST (Advanced Industrial Science and Technology) have
advanced largely in the holographic imagery. The technique rests on the cross
use of several beams laser. Result: a luminous plasma in relief appears and
floats in the air. The infra-red beams release from the luminous points in space
and are reflected by mirrors laid out except for the micron. An image takes
shape then right in the middle of this device. Small secrecy: so that this image
plasma appears, it is necessary that the environment is charged out of vapor
concentrated in electrons and ions but whose exact composition remains unknown.
Sure that the cinematographic technicians go ruer above as of its marketing
A film stripped of all emotions is unquestionably missed. Imagine Jurassic Park
with dinosaurs out of paperboard paste or many scenes of action without
explosion on all the sides? Unthinkable.
The objective of a scenario writer is to divert the spectators and of their
putting full the eyes of them. The special effects fill this role and this of
various manners. Models, make-up, prosthesis, sound effects, accessories,
puppets, data processing… the world of the illusion contains an incredible
number of technique.
The true revolution with the cinema took place with the appearance of data
processing and the numerical one. Previously, the special effects were already
remarkable, with the image of Wars Star of George Lucas, success with the box
world office. Thanks to software, realism is multiplied by ten and the facility
of realization is much more important. Radioscopy, morphing, warping, motion
control, etc work to create astonishing virtual decorations. Moreover, the world
of publicity uses more and more with these technical processes.