ARRI 300 with a sheet of Rosco Tough Spun Diffusion.
In recent issues, MicroFilmmaker Magazine has begun introducing our readers to lighting concepts and practical techniques to polish the look of their productions. In this installment, we’ll take a look at two types of tools that will significantly augment the look of the lighting scheme and allow users to not only add creative flare, but also compensate for and correct lighting problems. Just as I recommended that you invest in quality lighting hardware, such as the ARRI 300/650 Fresnel Combo Kit we reviewed in our December double issue (which we are also using in this test), I also highly recommend that you invest in a few gel filter and diffusion kits. The versatility you will gain when employing these tools far outweigh the modest financial cost of purchasing them. While there are a number of diffusion and gel companies, in today’s article, we’re using gels and diffusion provided by Apollo Design Technologies, Inc. and Rosco, Inc. (Apollo tends to specialize most in live venues such as stage and concerts, while Rosco specializes in television and film supplies.)
Apollo's selection of gels tend to be designed for theatrical and concert stage shows, but can be used by filmmakers easily enough.
Gel filters have two primary purposes. One purpose is to provide a means of raising or lowering the color temperature of light sources. Usually the source is either tungsten (emitting an orange tint) or daylight (emitting a blue tint). However, there are other sources such as fluorescent lamps (emitting a green hue) used in many office spaces, mercury vapor sources used in street lamps or warehouses, and sodium vapor or metal-halide sources. Applying gel filters in varying colors and combinations will easily and effectively create several variations in the color temperature of light emitted. The other purpose of gel filters is to change the visible color of the light altogether. This is particularly advantageous in film and theatre scenarios in which the lighting sets the tone or emotion of the scene. Both Apollo and Rosco manufacture kits that include a range of gel filters to address these purposes. While Apollo categorizes their product by theme (Theatre Pack, Concert Pack and Variety Pack), Rosco groups their gel filters according to intended use. Those received by MicroFilmmaker include Cinegel Sampler, Color Correction, Color Effects and Calcolor (calibrated color) kits. Both companies' kits include red, green, blue, yellow, magenta and cyan.
Because Rosco specializes in cinema and television, they have a wide array of gels for everything from color correction to color enhancement to diffusion.
When considering which gel filters are appropriate in a given scenario, the goal is to balance all other light sources to the reference source—the primary light source exposing the main items of interest. Equally, it is important to recognize that gel filters should be used to provide color correction or effect to specific elements within the scene. Overall color correction and/or color scheme effects for a scene are most commonly created using lens filters affixed to the camera or, more commonly, in post-production. Recognizing the purpose of gel filters should free the gaffer from added pressure to address problems not intended to be solved by these products. If gaffers are unsure in general about using gels and the principles involved, they will find the Rosco Filter Facts booklet included in all Rosco gel kits extremely valuable. Inside are instructions and formulas that will quickly enable users to determine the appropriate selection. The Apollo kits do not contain a handbook, but a gel swatch book is available including usage guidelines.
Swatchbooks can help you find which color gels are right for your project and even let you cheat the white balance on your camera if used creatively, like this one from Apollo.
