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Do Blue River Digital's light boxes come with fluorescent bulbs?
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Yes, all Blue River Digital's light box models come with fluorescent tubes. Some models have the tubes pre-installed, while others come with the tubes packaged separately, for customer installation.
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Can I buy replacement fluorescent tubes for my light box, from Blue River Digital?
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Since all Blue River Digital light box models use standard, off-the-shelf fluorescent tubes, and since fluorescent tubes are fragile and difficult to ship safely, we recommend that you purchase replacement fluorescent tubes from a local hardware store.
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Do Blue River Digital's light boxes come with acrylic lens?
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Yes. Most models include 2 lenses: a white diffuser (to go behind your graphic), plus a clear front lens. A couple of models include only the clear lens, and are intended for use with Duratrans graphic prints that provide their own diffusion property.
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I received my new light box from Blue River Digital, and there is a blue (or white) film on the lens. What is that for, and should I leave it on there?
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The film on the acrylic lens of your new light box is there to protect the acrylic from scuffing during fabrication and shipment, and needs to be removed prior to use.
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I received my new light box from Blue River Digital and when I plug it in, it doesn't light up.
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Here is a short list of reasons why a new light box may not light up when plugged in, plus recommended solutions:
1. Occasionally during shipping, the fluorescent tubes may shift in their sockets, and need to be re-seated. Simply slide or lift the acrylic lens(es) out and re-seat the tubes.
2. Some models are shipped with the fluorescent tubes un-installed, for safer transit. Un-installed tubes are usually packed inside the light box, behind the acrylic lens. Slide or lift the lens(es) out, locate the tubes and install them into their sockets by hand.
3. Many Blue River Digital light box models include an opaque, protective film on the acrylic lens, to protect it from scuffing during fabrication and shipment. If not removed by the customer, this film will prevent the light from showing through the lens.
4. Check to see if your light box is configured with an on/off switch, that needs to be toggled. Some models have a switch on the back or side of the unit, while others have an in-line switch on the power cord.
5. Occasionally, a freight carrier may drop a cartoned light box during transit, causing one or more fluorescent tubes to fracture. Inspect the tubes for cracks and if found, submit an RMA.
6. Confirm that the power spec of your new light box matches that of your local utility. All Blue River Digital light boxes are designed for use with 120 volts AC at 50-60 Hz, unless custom-ordered otherwise.
7. Use another, working appliance to test the socket you're using to power the light box, to confirm the socket is working properly.
On the rare occasion that your new light box still does not light up, there may be a defective ballast or wiring in the unit. In this case, please submit an RMA to Blue River Digital for prompt replacement or repair.
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On the specs for the fluorescent tubes, what does T5 (or T8, T12 etc.) mean?
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This designation is the diameter of the fluorescent tube, in eighths of an inch. So T5 is 5/8" diameter, T8 is 1" diameter, and so on.
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What are ways to increase the uniformity of light diffusion in a light box display (that is, how can “hot spots” and/or shadows in the backlit graphic be minimized)?
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There are several factors influencing the diffusion in any given light box. Some are engineered into the various light box designs, while others can be altered post-fabrication:
1. Content of the graphic. Artwork that contains large light-colored, solid areas is the most susceptible to visible hot spots and/or shadows. If you have control over the artwork, and if uniform diffusion is critical, then try to minimize solid, light-colored areas. Variated, dark textures with intermittent light areas will yield the best apparent diffusion, and also the most contrast and visual appeal.
2. Distance between graphic and light source. The best way to achieve solid, uniform diffusion is to increase the distance between the display graphic and the source of light. Conventional fluorescent light box models that have a case depth of 5" or more will produce the most uniform diffusion, almost regardless of what other measures are taken.
3. Diffuser layers. The most common diffusion configuration is to place a graphic that is printed onto a diffused film (such as Duratrans), on top of a single "sign white" or diffused white acrylic sheet, for a "double-diffusion" effect. Common alternative diffusers to acrylic include styrene, polycarbonate, and PETG or APET plastics. Although styrene yields effectively the same diffusion as acrylic and is less expensive, it is more susceptible to cracking and yellowing over time. Polycarbonate is generally more expensive than acrylic and extremely crack-resistant, but for some discriminating applications such as fine art display, its diffusive properties are not as desirable as acrylic. PETG and APET plastics also generally cost more than acrylic, and are less available, although they are more crack-resistant, and yield nominally better brightness.
The second-most common design, is to place a diffused graphic in front of the light source, with NO acrylic or other additional diffuser in between. This is common in outdoor applications where the case depth of the light box is 5" or more, which minimizes the need for an acrylic diffuser.
Adding diffuser panels (in addition to the first panel) behind a backlit graphic display, and/or increasing the thickness of the diffuser, are also methods that can yield a slight decrease in visible hot spots or shadows.
4. Type of light source. There are several backlit technologies in commercial use, and each provides a different level of diffusion (please also see What types of lighting are available?"):
a) Fluorescent Backlit — good diffusion, because the tubes are long and have their own soft, diffusive property.
b) Fluorescent Edgelit — great diffusion, except at the very outside edges (where the image is brighter), and in display sizes over roughly 36" x 48", in which case the center of the image may be slightly less bright.
c) Electroluminescent (EL) — excellent diffusion, although not as bright as fluorescent, and fading over time.
d) Cold Cathode Fluorescent (CCFL) — same diffusion pattern as Fluorescent Edgelit, because CCFL uses the same lamp-and-carrier arrangement, except that CCFL is brighter.
e) Light-Emitting Diode (LED) — depends on the layout and spacing of the lamps, since individual LED lamps are small and very bright, and therefore more focal and concentrated.
5. Etching. Some of Blue River Digital's fluorescent edgelit light box models include a special etching on the diffuser panel, which helps to scatter the light more uniformly.
6. Bulb tape. Some of Blue River Digital's low-profile light box models include a special translucent tape pre-installed on the fluorescent tubes, to further promote uniform diffusion.
7. Interior surface treatments. White paint, as well as various specialized finishes and textures are applied to the interior surfaces of many light boxes, to help the light reflect randomly and uniformly.
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What types of lighting are available, for backlit display light boxes?
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There are currently a total of 6 different lighting technologies being used in the backlit display light box industry:
1. fluorescent backlit - this is the most common backlit technology, due to economy of materials and manufacturing, low heat output, resistance to vibration, and relatively uniform light distribution across the face of the light box display. Also, broken or worn out fluorescent tubes are usually easy and inexpensive to replace with common, off-the-shelf tubes.
2. fluorescent edgelit - using 2 small-diameter fluorescent tubes (typically T-5 size), one at each opposing edge of the graphic window, plus a special light-diffusing film running edge to edge behind the light box display window, "edgelit" light boxes create a soft, mostly uniform backlit environment that allows for very shallow case design, under 1.5 to 2" total depth. The downsides to edgelit light boxes are that (a) the overall brightness is less than that of common fluorescent; (b) the 2 edgelit, outer edges of the display are often brighter than the body of the display; (c) most edgelit light boxes can introduce a slight bluish cast to the displayed graphics, depending on the content and color of the artwork; and (d) the brightness of edgelit drops below acceptable levels for commercial backlit display, when the display size exceeds 36 to 40 inches in the shorter dimension.
3. electroluminescent or LEC (light-emitting capacitor) panel - a flat and flexible film resin first developed by Sylvania that glows when charged, this material is not as bright as fluorescent but results in an even shallower overall depth of light panel, as low as 0.02" total thickness. Electroluminescent technology requires special inverter hardware, which results in a much higher cost per square inch. Electroluminescent yields highly uniform light distribution across the backlit display surface. Electroluminescent panels not only start out with a softer, less intense light level, but also begin to fade in intensity within 1500 to 3000 hours and eventually fade to a less than acceptable level for even the softest backlit applications, requiring replacement of the entire panel (there are no "bulbs" or elements that can be changed out).
4. cold cathode fluorescent lamps or "CCFL" - this is a brighter, more intense form of fluorescent. Cold cathode technology is more expensive than fluorescent, although the lamps are claimed to last up to 30,000 hours or more, as compared to a few thousand hours for normal fluorescent tubes. Replacement CCFL tubes can be difficult to acquire and expensive to replace. Also, many CCFL light boxes have soldered (low-temp welded) connections, rather than plug-n-play sockets as normal fluorescents do.
5. light-emitting diode or "LED" - this technology promises to deliver a cleaner, brighter lighting alternative to the backlit display light box market, with almost no heat generation, and with a longer life expectancy than any standard light source. Although quite a bit more expensive than fluorescent when compared square inch for square inch of lighted display panel, the cost of LED is expected to continue to fall in the future, and LED uses just a fraction of the power that other lighting technologies use. Also, depending on the design, LED light boxes can generally be fabricated in thinner case depths than standard fluorescent. Very few LED light boxes are available on the market at this time, and almost no LED light boxes are being offered at display sizes over 18-24 inches.
6. studio lighting - specific to the media and photography industries, many backdrops and scenics are backlit using various in-house studio lighting configurations. The main advantages to this approach are (a) you can light a much larger area for a much lower unit-area cost, because you're not paying for a metal housing (light box), only the imaged backdrop material itself; and (b) increased control over the intensity, focus and hue of the lighting. The downside, other than the obvious fact that you have to provide your own lighting, is the creative planning necessary to "mask off" the outer edges of the backlit display, to prevent stray light from coming around the edges.
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It seems that halogen and/or incandescent lamps can be extremely bright, as well as relatively inexpensive to replace. Why aren't either of these light sources used in backlit display light box applications?
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Both halogen and incandescent sources (a) generate high heat; (b) consume excessive energy; (c) don't easily produce uniform light distribution [diffusion]; and (d) are highly susceptible to filament damage from vibration or impact.
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What about neon, or fiber optics for backlit display light boxes?
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Fiber optics and neon are of course being used in various sign and display configurations, but neither has the intensity or diffusion properties necessary to produce bright, uniform light distribution on a large backlit display panel, as other lighting technologies do.
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