Tasteful Lighting Effects

In Uncategorizedby tfwm

How to Create Lighting Effects with Basic Instrumentation

In doing research for this article I went to a book, “Modern Theatre Practice” written in 1939. I found it fascinating that the basic concepts for the effects we use today have not changed. The technology has improved in the quality but not he underlying concept. In this article I would like to introduce you to the world of effects using some simple accessories that are available for the faithful Ellipsoidal Reflector Spotlight. Before we start, we need to understand why this fixture can be so versatile while our favorite Par and Fresnel’s are limited to just color and size.

As I teach in my lighting classes, you can divide all fixtures into two categories: spot and wash. The wash category contains a selection of different fixtures that include Pars, Fresnel’s, Cyc lights, etc. The spot category contains only one type of fixture, the Ellipsoidal Reflector Spotlight. As the name implies, the spot category uses an ellipsoidal reflector, the wash category fixtures employ a variety of reflectors from circular to parabolic. The ellipsoidal reflector focus’ all of the light from the lamp that strikes it thru the second focal point of the ellipse. This focusing of the light rays keeps them in alignment as they pass through gobos and then are focused by the lens systems.

Any other reflector, while directing the light rays forward, does not focus them so that you can project an image. The old Batman show that has a searchlight with a parabolic reflector projecting an image to summon Batman is a TV fantasy. You can create some wonderful shadow images, such as tree shadows or window blinds by using real window blinds and fixtures placed a distance behind them. This effect works best by having distance between the fixture and the object used for the shadow. The effect is a recreation of nature.

Another effect you can create with wash fixtures is water reflections. This effect is created using real water in a shallow pan with a reflective bottom. If the pan bottom is not reflective enough, you can add a layer of shiny aluminum foil. You can also add some strips of gel on the bottom to provide shifting colors. By using the physics of mirrored surfaces, the angle of incidence will equal the angle of reflectance. So, by pumping enough light at an angle you can cast reflections onto the back of your set, and to add movement, just disturb the surface of the water; simple but effective. As you change the angle of the light you change the reflectance and the area of coverage.

Effects from Scratch

While the aforementioned are great effects, this article is about how to create effects without real elements. By using an ellipsoidal reflector spotlight you can create an impressive array of effects. All of these fixtures have an area in front of the reflector called the “gate”. This location is where you can place an image for focusing. In fact, the gate is where the shutters and a series of plates to hold the shutters in place are located. The plates perform two other duties; one is to block stray light rays, the other is to provide a circle pattern. So when you focus an ERS fixture, you are projecting a pattern.

The simplest effect is the projection of a gobo onto the stage. Start with an ellipsoidal and a gobo, or pattern (these two words are used interchangeably, so I’ll stick to “gobo” for the rest of the article), and you can project any image you want.

Gobos, focus and Plastic

First let’s examine the gobo. Gobos have been around for longer than I can remember. The first gobo was probably created soon after a lens system was designed for an ellipsoidal. The basic gobo in the beginning would have been crude and only good for breakup looks, or the effect of light through foliage. In the early ‘80’s I designed and made custom gobos as a sideline. I would start with thin sheets of aluminum or brass, depending on the fixture and how long the gobo had to last. I would draw the image on paper to size, then coat the sheet metal with an acid resistant material and transfer the pattern to the resist. The next step was to scratch through the resist to the metal. Now came the real fun: placing the prepared sheet into an acid bath until the metal etched thru to the other side. When the etching was complete, I would rinse the sheet and remove the pieces of excess metal, then file away the rough edges. If the image was to be sharp focused I would have to spend a fair amount of time on the filing because an image only 4” in diameter could end up as 15’ in diameter and any imperfections would be greatly magnified.

Soon after I started making gobos, the Great American Market started to sell gobos at a price I couldn’t compete with. Their process consisted of mass etching very thin steel in a fancy photo resist double sided spray etching process. This has become the standard for the basic gobo sold today by at least four major manufacturers and a host of smaller companies. Now you can order custom gobos and get them in 3 days or less. One company stocks over 100,000 gobos in inventory. When you go to order your gobos you will need to specify the size based on the fixture. There are eight different sizes available to fit standard ellipsoidal and moving light fixtures.

Along with the standard metal gobos, today you can get photo realistic full color gobos, either in standard offerings or custom versions of any submitted artwork. Gobos can be used for a range of effects— from out of focus breakups to realistic clouds. In order to get the most out of your focused effects, we need to understand that not all of the light rays go where you want. The optics in standard ellipsoidal fixtures is at best only medium on an optical scale.

Ever notice that your image isn’t quite in focus? Well, by nature of the beast, some light rays stray from perfection. To help sharpen the look of the image, you can place what is called a “donut” in the color frame holder at the front of the fixture to catch the stray beams. The gobo manufacturers all sell a one-size-donut-fits-all, but I remember the days before mass production when we would custom make donuts from aluminum pie plates. In order to figure out the diameter of the circle we would use a large iris. By placing the iris in front of the fixture we could ‘iris down’ until the image was well focused, then we would cut out a circle to match. I will mention at LDI 2005, ETC introduced the “Enhanced Definition Lens Tube”, which finally offers a good optic system for gobo projection.

Another problem with older fixtures was getting your cross to be level, or straight. The first innovation was to make a gobo holder that would hold a round pattern in a tight fit. Of course you have to be careful when you make adjustments, as the temperature at the gate of the fixture is very hot and the pattern can burn you even after a short exposure. The next innovation came from the fixture manufacturers; they figured out that they could make the barrel of the fixture rotate from the gate forward. So now you can rotate your pattern without burning your fingers, and before I forget, gobos are inserted upside down and backwards.

One last innovation that is available in the gobo market today is the use of plastic slides as gobos. Rosco Laboratories offers a device called the ImagePro that allows you to print a slide with an ink jet printer onto a polyester film. This means any image in any color, in your timing. There are some restrictions on which fixtures and durability. They claim 15 to 50 hours of use without degradation at 100% intensity in the fixtures they recommend. The unit contains a fan to add cooling and makes use of infrared reflection and thermal barriers to protect the plastic slide.

Going Through the Motion

Static images are nice for some effects, but for a little more ‘wow factor’ we add movement to the arsenal of effects. We can introduce movement in two locations, at the gate and in front at the color frame. At the gate, the simplest effect is to spin the gobo in either direction with a variable speed motor. Now you can turn people’s stomachs with psychedelic spinning wheels. The latest of these gobo rotators allows for a range of effects, simple rotation, indexed movement, and shake effects.

Now if I can get one gobo rotating, what about two? The double gobo rotator has been around for a number of years. Stomachs will turn even faster with the implementation of this innovation. You can get these units in two versions. The inexpensive version has one motor so both gobos will rotate all the time, with the option of which direction they are going. The more expensive version comes with two motors that allow for complete independent control over direction, speed, and position. I could go on about the varying effects here, but I want to cover more ground so I suggest you go to the manufacturer’s websites, where they offer recipes for how to create different effects. By combining fixed gobos with rotating patterns and color, you can achieve startling effects for very little money.

The second location that I mentioned for movement is at the color frame slot in front of the lens. This is a very old method of creating an effect. My introduction to a device in this location was a “Lobster-scope”. This device produced a strobe like effect by rotating a disc at high speed. The disc was mostly solid with only two slits cut in 180 degrees opposite from each other. This device available was before strobe units were affordable. Today the units are designed to work by rotating at slower speeds and breaking up the static gobo image so that it appears to move or sparkle.

Making A Scene

The last device I would bring to your attention is a scenic projector. In my “Modern Theatre Practice” book they show a fascinating effect machine called the “Sciopticon”. This machine used a large lamp body about the size of a followspot, with a round motorized section and then a lens tube. In the round section you would place a disc made from thin mica, onto which you could paint an image which would then move (to make an effect such as clouds). Today we can get a scenic projector insert for the ETC Source 4 ellipsoidal from two different companies. City Theatrical offers the EFX Plus2 unit which is a large format disc projector, capable of having two discs, and complete control over each disc. The unit also has a slot for Art Glass that allows for a static pattern that will enhance the feel of movement.

The benefit of a large format disc over a rotating gobo is for the image to appear to move continuously. You can now project the image of clouds moving across the sky, or have flames continuously move up, and not just twinkle. The effects are mainly geared towards clouds, flames, water, and rain; although they also offer a Lobster Scope and a Flicker Wheel.

Scene Machines

The Great American Market or GAM has been offering a scene machine for over 25 years. The Scene Machine is a modular unit modeled after the Sciopticon of years past, with major improvements. The unit is still an ellipsoidal fixture, although it is one that comes in pieces. This unit has been used for years in major theatrical productions around the country, and it is expensive. What the Scene Machine offered was not only the large format disc, but also film loops made from steel. The film loop eliminates the look of the clouds always rising on one side and falling on the other as happens with a disc.

A few years back, in order to meet the growing demand for effects at a less expensive price, GAM came out with the SX4 unit which fits an ETC Source 4 or Altman Shakespeare unit. They offer four different trays, Loop, Disc, Six Gobo, and Four Gobo, along with options for shutters with each tray. The trays are interchangeable in the housing so you don’t have to take the whole assembly apart to change effects.

While I’ve mentioned color briefly, I wanted to make sure I cover the importance of color in creating effects and some of the fun toys available beyond the standard gel. Starting with standard gel, in a previous column I detailed the use of split gel or multiple gel colors taped together to create an effect. This works very well when creating fire and water effects, as well as the simple garden scene with leaf patterns. Also available are colored glass patterns that can be used at the gate of the fixture either by themselves or with a pattern. By placing the color at the gate you maintain the individual colors in the pattern so that you create images such as a stained glass window.

I hope I have opened your eyes up to some of the effects you can create for a small amount of money that will enhance your productions using a fixture you are probably already familiar with, the ellipsoidal reflector spotlight. I would encourage you to go check out the websites listed below for more ideas and recipes. As always, have fun and happy lighting!

Quick Links

Rosco Laboratories – www.rosco.com

GAM – www.gamonline.com

Apollo Design Technology – www.internetapollo.com

City Theatrical – www.citytheatrical.com