Light Source: The Illusion of Diffusion (page 2)

Diffusing Gel

One of the most useful tools for light diffusion is the gel. There are more than 20 different types of gels you can use for diffusion. Gels are usually placed in five categories: frost, spun, diffused white, silk and grid cloth.

A frost is a soft diffusion gel that spreads the light beam evenly yet maintains a center and a defined light edge. It is ideal for spreading the beam of a light source while maintaining its characteristics. Frost gels are helpful when duplicating room lighting, such as lamplight. You will still get the round throw of what looks like the lamp's light, but with get a softer shadow. Frosts comes in a variety of thicknesses so you can vary the effect to meet your needs.

Diffusion material, or "tough spun," is made of a heat-resistant material that looks like spun glass. You can drape it over the front of lighting instruments using a technique called "diapering." By clipping diffusion material over the front of a lighting instrument, you can spread the light's beam without changing its shape, getting a more diffused but defined light source. Use tough spun on the front of an instrument to soften the light for younger actors who do not need as much diffusion to soften their looks. It is great material to work with because you can shape or drape it over anything. This material also comes in a variety of thicknesses.

Diffused white gels are thick, translucent gels that spread the light beam to create an even splash of light with no defined center or edge. These gels are ideal for creating soft shadowless light, much like that on a cloudy day.

Silk is a type of gel material that has a definite linear texture. Silk gels spread light in one direction, ideal for sending light across a set or specific object. Because it diffuses light in a particular direction, you can use it on several lights to eliminate the scallop effect created by spacing between the lights. Silk is also useful in controlling the light coming into the set at extreme angles.

Grid cloth is a diffusion material that has a built-in grid that creates a material strong enough to sew or grommet. This material is ideal for making lighting tents and butterflies.

Butterflies, Tenting and Softboxes

Attaching gels to the front of front of lighting instruments is the simplest way to diffuse light. There are however, a number of ways you can expand diffusion characteristics to light large or intricate settings.

A butterfly is a large diffusion tool that stretches over a solid frame. Directors usually suspend a butterfly over the object or subject they are taping and illuminate it with a number of lighting instruments hung above. Commercial directors use the butterfly to provide a large, even light over a shiny new automobile. They suspend the butterfly over the car and use the soft white reflection of the butterfly to give the car a three-dimensional look as well as make it look smooth and powerful. The light from the butterfly is almost shadowless, so it can evenly light an area and provide a soft, glowing ambience to the scene. Butterflies are also used outdoors (be careful, though they make great kites). If placed between the sun and your subject, you can use the sun's light without having to deal its harsh shadows.

Tenting provides a soft, diffused light throughout the shot. You can drape grid-cloth like a tent over your subjects to surround them with a shadowless soft glow. This technique is often used to light objects for commercials.

A softbox is perhaps the most used diffusion tool in the industry. The softbox is a large box that fits on the front of the lighting instrument and diffuses the light in a very specific direction. It provides a great way to turn a 6-inch light with a very hard beam into a 24-inch light with a soft, diffused beam. This is ideal for people, because it softens and evens out skin tones. Directors also use softboxes when lighting shiny surfaces, so the reflected light sources aren't just little spots of light.

Final Thoughts

Using diffusion is as simple as placing a gel in front of a light. However, you need to experiment with a variety of diffusion materials to learn what works best for your lighting situation. Remember that shadows are not bad, you just have to control them. With diffusion materials and techniques, you can control the amount and intensity of the shadows. By learning the ins and outs of diffusion, your talent will look younger and your products will sparkle.