Heat Waves can be desired or a problem. The factors involved are the temperature
of the ground or surface under the lens between the lens and object, the height
of the lens from the surface and the wind. You can increase or decrease the
effect by varying these factors. Heat from Sterno can work, but can be very
uneven if there is much wind. A black or white card under lens can effect the
amount or waves. Moving the camera up or down on a crane or short linear dolly
can vary the effect during a shot. And a video finish could give a similar effect.
Reflections in water can be created with very shallow pools of water in black
visqueen. Keeping it clean and getting a believable edge can be a problem. You
have to look at it at a very shallow angle to not see the bottom.
We have simulated the light from a moving train windows with mirrors on a long
pipe between two dollies behind camera. Mirrors on a 4' diameter plywood turntable
simulated reflections from car roofs driving by a bright theater entrance.
A mirror can move a light pattern easier than moving the light itself. Patterns
of any light other than the sun get larger further from the light. (Sun light
off an imperfectly flat mirror gets larger too.)
Slide projectors are well-collimated and economical light sources. Making a
bale from an old 2K-freznel light makes them easier to adjust. A 14" square
piece of plywood screwed to a 3/4" pipe floor flange with a 4" piece of 3/4"
water pipe makes a flat platform for a 2 K 1-1/8" stand. Wedges allow adjustments.
Mattes can be drilled or cut to fit where a slide usually goes. Consider shooting
high contrast patterns to project on a scene. If you want to project a large
pattern you will need a bigger unit than 500 watts.
Mee Fog. There are commercial units for sale and rent to make real fog from
water. The commercial units use regular water filtered inside and need electricity.
On location pressure washer pumps will create the minimum 1000/2000-psi. needed.
The water has to be filtered to prevent the very small holes on the fog heads
from getting clogged. 3 stages of filters will keep the last and finest filter
getting clogged too fast. Regular household filter units will work fine, but
they need some intake pressure to keep their relief valves closed. Raise your
water supply above the filters.
The fog heads can be ordered on 10-foot long pipes that can be connected with
high-pressure hose fittings. The fittings can not be disconnected under pressure.
Pipes have to be drained and dried after use to avoid corrosion and rust. Use
all brass fittings and copper tube if possible.
Compressed air bottles can be pressurized with nitrogen to provide a small amount
of fog for portable use. CO2 at 800 psi will dissolve in water but is safer
to handle than nitrogen at 2000 psi. Using distilled water and keeping tanks
clean and rust free is necessary to avoid head clogging.
The heads are very fragile and have to be stored and handled carefully. In Hollywood,
Roger George has quite a collection for rent.
Dust can be made reliably with an industrial size flour sifter and a small DC
gear motor to turn the handle.
Larger dust effects can be made with Penburthy steam injectors and large quantities
of air or compressed gas. A large funnel can supply the dust material to the
Penburthy injector. A Penburthy injector is a brass venturi that sucks liquid
or powder with a stream of air or liquid. DEALING WITH COMPRESSED GAS AND FULLER'S
EARTH IS DANGEROUS. DO NOT BREATH FULLER'S EARTH. USE ONLY HIGH PRESSURE HOSES
AND FITTINGS WITH COMPRESSED GAS.
I have avoided "cracked" oil fog effects because the effect on crew and talent
is questionable. Mee Fog is pure water, but gets a set wet and doesn't last.
It will create great ground fog.
Ground fog can also be created with fog machines and dry ice. It has to be dead
calm. Spraying small fog machines into wet grass can cool the fog enough for
it to "hang" low to the ground.
Working with large foggers can be frustrating as the wind seems to shift a lot.
Radios or monitors with noise reduction headphones are very helpful to give
the fog machine operators instructions. Give instructions of what you think
will get the right effects. Don't expect the operator to see your desired results
from his perspective. It is usually calmest at sunrise.
Propane insecticide sprayers will work with "fog juice", but they are very temperamental.
The Electric Mole types are much more reliable but need 110-volt power.
A good way to apply a coat of dust to cars, windows and large shiny objects
is with water and Fuller's Earth in a paint spray gun. You can "dull spray"
large areas. If you don't like the effect, wipe or wash it off and try again.
Windshields look great. You can run the wipers after it dries for a realistic
look. Don't spray a second coat until the first coat dries. Clean and dry the
spray gun after use. Water will remove the fuller's earth. AVOID BREATHING THE
If is difficult to make realistic mud splatter around wheel wells. It can save
time to dig a mud hole and drive through it.
To darken pavement and wood, water works fine. Water fire extinguishers can
be pressurized with spray nozzles fitted where the stream nozzle was. You have
to be careful to not make puddles that reflect light. For large areas a large
fire fog nozzle and a fire hose will work. Water fire extinguishers can touch-up
smaller areas at they dry. Applying subtle effects takes people with experience
or training. Don't expect a kid new on the set to handle subtle effects. Hire
experience and intelligence. Most effects are perfected by observing the results
of an action and modifying the treatment to give the desired look. It's called
problem solving. Testing beforehand is very wise.
Water fire extinguishers can also apply poster paint to cover white lines on
pavement etc. Poster paint can be then washed off. Clean the extinguisher afterward.
Hudson sprayers also work, but the fire extinguishers are better although they
need a source of air pressure.
© Copyright 1999-2004 Ron Dexter. All Rights Reserved.