Polymers in Film Production

FILM LIGHTS SOUND CAMERA EDIT

LIGHTS Director: LIGHTS!

One of the most important ingredients in a movie besides the film is LIGHT. Lighting is one of the least noticed and most critical elements in a film. It is what determines what images will be recorded on all that expensive film stock, so it has to be right before we shoot a single frame. Each kind of film is sensitive in different ways to the color and brightness of lights. To make the lights suit the film stock we use, we employ filters or gels. Filter and gel materials are made of... you guessed it - gelatin which is tinted with very specific colors or diffusion to change the mood of a scene or to simply make the light match the type of film we are shooting.

If we shoot indoor film outside we have to use an orange 85B filter in the camera or on the camera lens or else the whole scene will look blue due to the "hotter" color temperature of sunlight. And if we use outdoor film inside, we use an 80A blue filter to give artificial lights the same color temperature as the sun. The best way to change the temperature of artificial lights to match daylight is to put the filter material directly over the light source, since putting a dark 80A filter in the camera cuts down the speed of the already "slow" outdoor film. The colored transparent filters are clipped to the "barn doors" of studio lights to filter the light to the right color, or they can be put into a ring that fits over the light as in theater lighting, but the lights are very hot and can melt through the gelatin before too long, so a lot of the modern filter sheets are made from polyester. We also use gels to change the mood of a scene. We can use a lot of dark blue gels to get the look of a moonlit night. Or we can use a gold gel to warm everything up for a sunset. Or we can soften the light with a frosted diffusion gel.

The lights themselves have few polymers on board except as insulators for the power cords which carry very large currents. This small light is 500 watts! And it takes a current of 5 amps, hence those big fat rubber cords. And lights, being pretty delicate with all those bulbs and filaments, are best transported in foam casing. Polyurethane foam works great for making form-fitting transport material. And a lot of equipment cases are also made of thick high-impact polystyrene or polyurethane composited with nylon fibers that make them durable and much lighter than the older metal boxes.


Now we need a light meter to test the brightness of our surroundings. Light meters come with a variety of features and cases made of metal or plastic, but they all have a photoelectric plate that uses the light energy striking it to measure how much light is hitting a surface. To simulate 3-D surfaces the light is usually filtered into the meter through an opaque globe at the top of the meter, which is most likely made form polyester. The "3-D" and light transmitting qualities of the globe give a more accurate reading of the light hitting objects in the shot, and the meter is calibrated to properly read the diffuse light coming in through the globe. In some cases the globe can be changed out for a disc that gives a better measuremetnt if one is photographing a flat surface such as a sign or a wall.

Speaking of light, it's a good idea to make sure that absolutely no light gets into the camera. Even the slightest light leak can ruin tons of beautiful cinematography. Even though cameras and magazines are made to be light proof the added precaution of GAFFER TAPE is often emplyed. This stuff is specially made for film production and has a number of uses. It comes in two different widths and a stunning array of neutral colors - black, white and gray - And though it's name implies that it should be used to tape light fixtures and gels (The GAFFER is the head lighting guy on a film set.), another popular use for it is taping around the camera door and film magazine lid to be sure that no light gets in. Due to this alternate use, the smaller widths of gaffer tape are ususally called "camera tape." It is also used in the change bag to retape film cans closed after the exposed film is removed from the camera. The tape is made of cotton mesh (cellulose, a natural polymer) with a water-resistant polymer coating and a copolymer adhesive which makes it easily removable like masking tape, though it is much more durable.



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Special thanks to the University of Southern Mississippi Department of Radio, Television, and Film for the opportunity to get all the pictures on these pages and to Gregory Brust for aiding in the idetification of all these polymers.