Feature Story

Mouth Watering Exhibits

by Ruth Ellen Miller
President
NoUVIR Research
Seaford, DE

“Presentation" describes the color and beauty in the appearance of a fine meal. A gourmet chef is never interested in just taste. He goes far beyond flavor. Using all his knowledge and skill, a top chef pays close attention to how the food is presented.

The reason is simple. Each course must look spectacular. The color and composition must be right. Every detail is displayed to make the food look like it's worth the price. The food can have superb taste -- but if it doesn't have proper presentation it has all the appeal (and apparent value) of a "blue plate special." So a gourmet chef spends years not only learning the mechanics of cooking, but the very art of food appearance -- presentation.

The same is true for exhibits. The whole idea is to attract, entertain, educate and motivate viewers. Motivate. If you are a museum, you want to motivate viewers to come back, bring their friends, and become supporters and museum store customers. If you are a commercial retail store, you want to motivate the viewers to buy merchandise. If you are at a trade show, you want to motivate attendees to stand three deep in your booth.

You have a choice in how well you motivate, which is tied to your decisions on lighting. Unfortunately, many exhibits of outstanding artifacts are like the blue-plate special -- you see them with basic "cookbook" lighting. They are devoid of true beauty and excitement. The footcandles are there, but the presentation is missing.

Ordinary lighting can make outstanding artifacts look ordinary, even boring. The explanation is obvious. If you have an exhibit full of multi-million dollar artifacts, but no light, you are in total darkness. What do you see? Absolutely nothing!

Now what happens if you turn on lights that produce unnatural, color-distorted illumination? Since the only thing you see is the distorted light reflected from the exhibit, the only thing you will see is a color-distorted exhibit. The unnatural light fails to communicate the beauty. You fail to motivate. Therefore, superb presentation requires pure-white light.

Next, what if each object in the exhibit is sitting on a spotlight aimed directly into your eyes? Again, what do you see? Absolutely nothing. You are blinded by the glare.

What if the exhibit is surrounded by sources of uncontrolled glare? Many exhibits have backgrounds and ambient light levels that are too bright. They have reflected light sources, images of other artifacts, and often even your own image, as uncontrolled reflections in the enclosure glass. All these glare sources mask your view of the artifact. Therefore, in addition to white light, superb presentation requires precise control.

Presentation is as vital to exhibit designers as it is to a five-star restaurant. In display lighting, it is the difference between $2.95 Beef Stew and $29.95 Beef Wellington. Fortunately, in lighting there is no secret recipe -- just three simple ingredients: 1) Perfect color rendition; 2) Excellent color balance; and 3) Precise control.

1) Color rendition.

Lamp manufacturers advertise the CRI (Color Rendition Index) for their products, with 100 being perfect. The CRI test is just a rating of how many slightly different colors can be identified by a viewer. A perfect CRI of 100 is found in all incandescent lamps, such as halogen lamps. It means every color can be seen, because every color of light is generated by the lamp. However, a CRI around 87 is typical of gas discharge lamps, such as fluorescent and metal halide lamps. For fine presentation, a CRI of 87 (87% correctly identified colors and 13% unidentifiable) is a failing grade of F.

2) Color balance.

Few lighting designers understand color balance unless they are involved in film and photography. In those areas, it is such a common term that every one-hour photo print machine is calibrated against master color balance negatives every day...that's right, every single day.

This assures the print colors will look like the objects in the photographs and assures no distortion. Perfect color balance is light that closely matches natural sunlight. It is light with every color in the same amount. No colors are weak. No colors are dominant. It is all true colors in perfect balance.

3) Beam control.

Glare disables vision. To enhance vision the light must be controlled. The human eye sees the entire 180 field of view. It responds and adjusts the iris to the average light level over that entire field of view. Thus, a bright surround, or intense spots of glare, even if it's not where you're looking, constrict the irises. It makes you partially "snow blind." That glare can be anywhere in the field of view. So all those bright tin cans pointed down from the ceiling, all that extra spill light splashing on the wall, all those reflections in the case fronts, and even those brightly-lit signs reduce vision and inhibit enjoyment.

Look at the contrast. Note the presentation. You may ask, "Do colors really look that different to a viewer?" The answer is: "They certainly do!"

The next question is: "Which photo shows the true colors?" If you did not have the strip of the background color above the photos, you would not be aware of all the beauty you're missing. This strip is the same gray-brown velour floor and back wall in all three pictures. The correct color may only be seen in the beam on the case floor encompassing the saucer using the fiber optic light. Notice the dramatic distortion from the fluorescent and halogen lamps. It's awful!

Another clue the colors are off is the deep lavender pattern borders. The lavender looks brown under the halogen lamp and light blue under the fluorescent light.

Obviously, fiber optics is the only source that shows the real colors. The difference is dramatic, but you don't notice the missing colors unless the exhibits are seen side-by-side in a room all illuminated with halogen lamps, your vision adapts to the excess red and yellow light. It's like wearing amber-tinted glasses.
After a while the world looks natural, even though it is a far cry from natural light. It's a phenomenon called chromatic adaptation. Why do these exhibits look so completely different? The answer lies in the visible content or "spectrum" of each light source.

Poor Color Rendition
The standard of excellence in spectral distribution is natural sunlight, shown superimposed on the light curves. The spectral curve of a lamp lets you predict how accurately a light will show true colors ...or how badly it will distort them.

The first curve shows the relative intensity of sunlight at each light color (wavelength) compared to a cool-white fluorescent lamp. The fluorescent lamp has very poor color rendition, because it has gaps in the colors. The curve is not smooth. Instead it has peaks and valleys, and it doesn't look anything like sunlight.

To make fluorescent lamps more energy efficient, manufacturers by law must use "tri-stimulus" phosphors. Thus the lamps emit RGB (Red, Green, Blue) light. But it's actually three separate colors mixed as a "metamer" in your brain, not in the exhibit. "Metamer" has the same root as "metaphysical," meaning it's all in your head.This light really plays with your mind. But the object is not faked into believing it's full-spectrum light. Only half the colors in the spectrum are present. The other half are missing. The colors have gone AWOL. The object cannot display 50% of its colors. Yikes!

That's why the background turned green. There were no colors like the background in the light, so this is gross distortion. You can see the presentation stinks. You can't correct it. You can't filter it out...and you can't cover it up with gravy.

This is true with all gas discharge lamps. They are very cost-effective. They are good for business offices, discount stores or conference rooms. But they are the junk food of exhibit lighting.

Poor Color Balance
The halogen incandescent light spectrum is continuous, without the gaps of fluorescent lamps. You can identify two slightly different colors, so the CRI is 100. But the color is out of balance. You can see there is only a little blue, but a ton of red. Compared to the even balance of sunlight, all the colors are shifted toward the red end of the spectrum. There is six to ten times more red and yellow than blue and violet.
So the red swamps the object. You can't tell what the true colors are. The lavender glaze borders on the china pattern look brown. The tan case lining is yellow on the floor and orange on the back. The light looks like a mess hall cook saturated the presentation with red dye #3 brown gravy.
But halogen light fixtures are really easy to use. It's a no-brainer. Just screw lighting tracks to the ceiling and position halogen fixtures by trial and error...providing you really like saffron-colored light. Halogen light is roadside diner fare. It's sit-down, get-waited-on, pay-at-the-register food. It's nourishing, but it won't impress your date.

Natural Light Spectrum

The spectrum of acrylic fiber optic light is continuous with a perfect CRI of 100. But, unlike the unbalanced halogen lamp spectrum (its source in the projector), the fiber optics is carefully filtered to suppress the excess red and yellow light. Good fiber optic illumination has natural sunlight's color balance. This is gourmet presentation. There's one last ingredient you need for a five-star exhibit.

Beam Control
Quality exhibit presentation also requires precise control. You want to enhance the viewer's vision and help it work at its best. You do not want to disable it with glare. Remember, the human eye sees a 180 field of view and adjusts the iris to the average light level over that entire field. If you have bright surroundings, the eyes shut down their iris f-stops and people complain the artifacts are dim. If there are bright lights or glare from windows, they cannot see details. The artifacts should be at least two times brighter than anything else in the 180 field of view for the observer to clearly see the colors and details. This means if you have a limit of 10 footcandles on an artifact, everything else should be 5 fc or less (5 x 2 = 10).
When you remove glare, you win. People see better because their eyes let in more light. Viewers who see clearly become customers. Light sources must be controlled or hidden. Make sure your artifacts are the brightest objects in the room. Use parabolic snoots, baffles, barn doors or any control to keep the viewer from seeing the light sources.

The ultimate in beam control is the acrylic fiber optic luminaire. It is the only light that can be safely installed inside an exhibit case, providing heatless light with no external reflections. This precise light control adds drama to the presentation. Great presentation motivates. It sells. It's the gourmet feast of exhibit building.
Look at these examples. A 24" high figure of a red-tailed hawk is shown illuminated with three fibers of 4-watts each on the hawk, one fiber on the artificial flowers and one fiber on the background. This is a total of only 20 watts. Compare the same object lit with the 50-watt halogen light. Both are nice displays. But fiber optic lighting shows the true color and detail. Especially notice the eye, the white breast and the flowers.
Now check out the blue pitcher. This glass artifact is lit with a single 4-watt fiber. The control is so exact, the pitcher is precisely framed. Light refracts through it, making it glow and creates spectacular patterns.

This is the kind of presentation that motivates viewers to become customers. Of course, acrylic fiber optic lighting is new technology. Certainly lighting designers will have to learn some new rules. But there are no secrets, no mysteries and no surprise results. The lighting design is simple and logical, with precise photometry that will produce predictable results every time.

Superb presentation is a powerful tool to show the color and beauty of a display. State-of-the-art lighting design goes far beyond mere illumination. Displays can now be presented to look spectacular, appearing to glow with their own true colors.

Exhibit lighting is more than the mechanics of selecting and positioning light fixtures. It's the art of revealing the essence of displays, so the viewer appreciates their beauty and value. In a museum, a boutique, a retail store or a five-star restaurant, that art is exhibit presentation. eb