Working Washes

Posted on May 24, 2017

Photo: National Cathedral

From tucking a small LED wash inside a scenic element on stage, to using battery powered uplights to bathe great columns in a rainbow of colors, designers have never had more options when it comes to choosing wash light fixtures, or devising ways to use them. Ford Sellers, Senior Product Manager at CHAUVET Professional sorts out the options and offers some insights into finding the most effective wash light for your next project.

A wide range of lights from battens and cyc fixtures, to pars and battery powered uplighters are used for washing. Can you give us an overview of when you would use each different type of fixture?
“Sure. Every type of wash light has a set of qualities and features that help it perform better in certain applications. This may not be the only light you can use as a wash in this specific instance, but you’ll find that other fixtures will not be as effective in that application. So, my advice is to select the wash fixture that was purposely built for what you have in mind. Different fixtures do better in different applications.” (Editor’s note: a list of fixtures and their wash lighting strengths can be found at the end of this article.)

In general terms, when you evaluate wash fixtures for a project, what are the things you should look for?
“For me, the key considerations are the colors, optics, brightness, and beam angle. For instance, if I’m using a fixture for front light in a small theatre, I’ll look for full color pars (preferably ones that can make convincing whites, as well as bright punchy colors). I’d also want them to have a wide beam angle and a slight center peak in brightness, so that I can easily overlap them in a wash.

“On the other hand, if I am lighting for video, I’d want to have fixtures that can change color temperature — either variable white like the COLORado 1-Quad Zoom VW, or full color fixtures with pre-built color temperature macros like the Ovation B-565FC. For video, you’ll also want to create an extremely flat field so that you don’t end up with hot spots in the image, so a Fresnel is a good choice for both blending, and for close-up camera work.

“Then if I were lighting an event, I might want a par with a narrow beam for creating columns of light along walls or to accent architectural elements. Battery lights are especially effective here, as events are not always held in areas with great power distribution. If I wanted wash lights for a rental inventory, a fixture with Zoom would be critically important, since it would allow it to be used in a variety of applications.”

Does the type of color you’re projecting with a wash fixture affect how you would use that fixture?
“Not really – while it is more common to see lighter shades of color spread over larger areas, this is beginning to change, because LEDs are more efficient than incandescent lights at generating saturated color.”

Why is that?
“This is because the incandescent lights use subtractive color mixing to block out the color they don’t want. On the other hand, LEDs use additive color mixing to add in more of the desired color. This is much more efficient.”

We are seeing more scenic elements being washed from the inside today. This often requires using a fixture that can fit in a tight space. Any advice on micro washing?
“A major thing to consider is heat. Using an LED fixture can generate significantly less heat than even a small incandescent fixture. This means LED is much easier and safer to use in tight spaces. Another major consideration is beam angle. If you are lighting the same element that you’re hiding your fixture in, you may need an extremely wide beam angle, whereas if you’re hiding a light in a piece of scenery which is lighting something else, you may need a tighter beam angle, to maintain brightness at a distance. Finally, how well the color blends is a major concern when you have lights directly against a surface. If the light you’re using has too much separation between the colors, you can use diffusion or holographic diffusion (in LED fixtures) to even out the distribution. This can be a lifesaver.”

Any advice on using a wash light when you have to cover a large area?
“When you’re lighting a large area, it is often preferable to use a few overlapping fixtures rather than one high-power light. Using multiple fixtures can give you more control over the distribution, so that you can either balance the output or make the edges fade away more evenly. It can also give the illusion of one distant light source (like sunlight), because the angle that the light is hitting the stage can be the same on both stage left and stage right. If you were using one bright fixture from above one side of the stage, the light would appear to come from the top on one edge and the side at the other edge of the stage. Or, if the light is hung above the center of the stage it will appear to come from the left on one side, straight in at center, and the right from the other side of the stage. This doesn’t look natural.”

How about when you’re washing a super high area?
“When you’re lighting a distant or super high area, you may want to use one or two very bright fixtures with tight beam angles, and combine this with some small internal or hidden accent lighting. If the object is very far away, the audience will not be able to see it in as much detail. Slight differences in the angle of the light will be less important than having enough brightness to make it clearly visible. So, it may be easier to hide fixtures in the scenic elements and combine this with a bright wash fixture for overall toning. This can give you more control over how your audience sees the target.”

Has the growth of LED video panels affected how wash lights are used?
“Video panels are very, very bright. They tend to visually dominate any environment. Part of the reason for this is because you are viewing the light sources directly. This is like looking straight into the lights instead of looking at the stage where the lights should be focused. So, many designers are finding that they need to either separate the LED screens from the performance space (by moving them up above or far out to the sides of the stage), turn the brightness of the screens way, way down, raise the brightness of the other lights in their rigs, or some combination of all three of these strategies.

“This is one of the major reasons that the beam fixture has become a staple of live performance. Beams are the only thing that are bright enough to compete with the LED walls that are being used in major tours and productions. What does this mean for wash lights? Well, it means that some LDs are tending to increase the overall brightness in their designs that use LED video walls.

“On the other hand, some of the leading LDs have started to limit the brightness of their screens, use more subtle video content, or find other ways to separate the video panels from the visual picture on the stage. This is allowing them to still use subtle washes in their lighting and not become a slave to high brightness video content.”

Along those lines, can you dial up a wash light to be too bright?
“Contrary to popular belief, there can be too much of a good thing. The best LDs out there are masters of controlling the dark, as much as the light. Subtle changes in intensity and angle of light can have far more effect that just making everything brighter. Our eyes can get fatigued if there is too much light. So, be careful when you’re trying to make something appear brighter. Often the better approach is to turn the surrounding light down a little. This can give the same effect, without causing eyestrain in your audience.”

Is there a common mistake designers make in regards to evaluating wash lights?
“I don’t know about mistakes, but to me the best way to evaluate a wash fixture, or any other light, is to get a demo in my hands, so I can see how it performs in the environment that I plan to use it in. Comparing units based on specs can be very confusing, and possibly misleading.

“For instance, the lux reading of a fixture is a measurement of how bright a light is at a given distance. However, there are two areas where end users can easily misunderstand what the lux readings are telling them. First is the distance that the measurement is taken at. Second is the relationship between the beam angle and field angle.

“At CHAUVET Professional, we list the lux measurement for all of our units at 5 meters (about 16 1/2 feet), since we think that this is a reasonable throw distance for many applications – not from the lighting pipe to the stage, but from the fixture hanging below the pipe to the performer’s face. Beam fixtures are the only exception to this rule. They are so bright; we measure them at 15m to get a number that isn’t just ridiculously large. We don’t generally list lumens, as this tells us the total amount of light that a fixture is generating, but doesn’t say anything about how much of that light is getting to where the fixture is focused.”

So, it’s important to compare the lux of fixtures at the same distance?
“Yes, absolutely! Measuring the lux of all of the fixtures you’re evaluating at the same distance means that you can easily compare the readings. When you measure lux at short distances, you can get misleading results. For example, which fixture do you think is brighter? One that measures 1000 lux at one meter, 440 lux at three meters, or 40 lux at five meters? This is a trick question, they are actually all the same brightness.

“Brightness at a distance is governed by something called the ‘Inverse Square Law,’ which means that every time you multiply the distance by a given number, you’re decreasing the brightness by the square of that number (twice the distance is ¼ the brightness, 3x the distance is 1/9th, etc.) So, suppose your fixture is positioned one meter from your target and your light is making a two meter circle, when you measure your brightness it reads 1000 lux. If you moved to three meters away, your lux would drop to 111. Then it would fall further to 62.5 lux at a four meter distance and down to 40 lux at five meters. So, paying close attention to your throw distance when you’re looking at specs is critically important.”

Photo: Garou Blancan of Montreal’s XYZ Technologie Culturelle washes Theatre St-James with a collection of CHAUVET Professional fixtures

You mentioned beam and field angle influence lux readings, can you elaborate?
“Sure– two fixtures putting out the same amount of light can still have very different lux readings if their beam and field angles are different. I had a wise teacher once who explained this concept by using paint as an analogy. If a unit has a tight beam angle (you don’t spread out your paint very much), it will have a higher lux reading (be a thicker coat of paint), but it will not cover as much space. If your beam angle is very wide, then you will spread the light out more, but it will not be as bright (you will spread the same amount of paint over a larger surface).

“If your beam and field angles are close to each other, that means that you have a very even distribution (the paint is the same thickness at the center as it is near the edges), but you will have lower lux readings at the center (because the light is spread evenly all the way out to the edges). If your beam angle and field angles are very different, that means that you will have a peak in your distribution and a bright center, but the edges of your light will be dimmer. Understanding beam and field angles, and the inverse square law, will really help you get a better understanding of manufacturer specs when evaluating wash lights.”

Any other advice?
“Like all advice, anything I said here needs to be taken with a grain of salt. Every application is different, and it can be the unusual or unexpected use of light that ultimately is the most creative and eye-catching. There is nothing to say that you cannot use a cyc light as a downstage foot light, or a par to light your backdrop. Some of the most interesting and innovative lighting that I’ve seen used lights in a way that I did not expect. That’s what makes lighting design so special.”

Wash Light Fixture Guide
Par Fixtures – These are general use wash fixtures. Pars get their name from the type of reflector (Parabolic Anodized Reflector) that was used in the incandescent versions of the lamps. The old incandescent pars came in fixed beam angles from VNSP (very narrow spot), to VWFL (Very Wide Flood). LED pars usually have a round output, and come in a variety of beam angles. Some even include a feature to zoom from narrow to wide. The beam angle that you need is usually dictated by your application. A narrow angle is good for washing targets at a distance, or for accent lighting on a wall or cyc. A wider angle is used for more even washes of color when your fixture is hung closer to your stage, or when you’re trying to spread your light over a larger area. You can also purchase “linear diffusion” which can be used to emulate the elliptical projection that the old incandescent fixtures produced.

Fresnels – These general use wash lights get their name from the type of lens that is used (the Fresnel lens was originally developed for use in lighthouses!). They have a more diffuse output than a par, and are often used in systems (multiple units hung together) to provide very even washes of top light, or key-light for video. You see them used extensively in television and film to provide even, diffuse light for close-up camera work.

Battens (Or Strip Lights) – Named after the pipes that run across the width of a stage, these linear wash lights are commonly used for wall or cyc grazing, and as top/backlight fixtures, where they often fill a batten (thus the name). They’re also occasionally hung sideways to provide powerful sidelight (designers refer to this usage as Vertical Toning Strips). Many production companies like to use battens as foot lights because you can line the front of a stage very quickly by using fixtures that are so long.

Cyc Lights – These are fixtures that have been specially designed to provide very even washes of color across a cyclorama or backdrop. They’re designed so that units hang just a few feet from the cyc above, or at the bottom, to provide an even amount of light across the entire height of the surface. This is extremely difficult to do with a regular wash light, unless it is hung directly in front of the surface.

Battery Powered Uplighters — Designed to provide accent lighting in areas where it may be difficult to access power, these fixtures behave like a par with a tighter beam angle. This makes them well-suited for making columns or streaks of color across a surface. They are extremely useful for events where you want to introduce color across the entire environment. They can also be used as pars in events where you cannot run cables on the ground, or where you have limited (or no) access to power, like outdoor or tent events or museum galas. They are especially useful for events where time is limited for setup and teardown. In addition to battery power, they need to have wireless control to be useful in most applications. The WELL fixtures from CHAUVET Professional all use W-DMX from wireless solutions (in addition to the IR remote), so that they can be easily controlled from any lighting console.