Category: Industry

What is CRI?

Developed well over 50 years ago, Color Rendering Index (CRI) measures the ability of a light source to reveal the colors of various objects in comparison to the ideal (daylight) source. In other words, how similar an electronic light source (like an LED luminaire) renders colors compared to natural light. 

CRI indexes eight standard colors and how these are represented by a specific light source compared to natural daylight. 100 is the optimal ‘best’ score. The average CRI for modern LED lighting is between 80 – 90, and are considered a “good” color representation, relatively true to nature.

Why a New Metric?

Well, since around 1974 the method for measuring color rendering has been largely unchanged – unlike the advancement of lighting and technology. With LED lighting now so common, lighting designers and scientists strongly feel CRI is becoming less effective at achieving desired results in the real world. While many lighting professionals will continue to work with CRI, TM-30, developed in 2015 by the Illumination Engineering Society (IES), provides an alternative, more comprehensive color index.

What’s the Difference Between CRI and TM-30?

CRI has some limitations:

• Only eight color samples are tested for CRI.
• CRI only uses color fidelity to base its index score, ignoring other spectral values.
• When comparing CRI values, Correlated Color Temperature (CCT) must be identical. 
• Two separate light sources with the same CRI score can render colors very differently.
• A high CRI measured rating could produce or represent a low TM-30 score.

CRI measures just 8 color samples. TM-30 uses 99 color samples – quite a difference! The use of 99 color samples versus just eight allows for  a more statistically representative and reliable metric.

CRI is measured using a light fidelity metric ONLY. The TM-30 rendering index uses a more comprehensive range of three color metrics:

• Color Fidelity (Rf – “same-ness” index)
• Color Gamut (Rg – saturation index)
• Gamut Shape (visual description on hue and saturation)

Color Fidelity: Enumerates the accuracy with which the color appearance of surfaces and objects under a given test source match their appearance under a reference illuminant.

Color Gamut: Enumerates the average increase or decrease of the chroma of surfaces and objects when viewed under a given test source relative to when viewed under a reference illuminant. As an example, an Rg value below 100 indicates that, on average, the light source renders colors as less saturated than the reference source, and an Rg value above 100 indicates that, on average, the light source renders colors as more saturated than the reference source.

Color Vector Graphic: Provides a visual representation of hue and saturation changes occurring in surfaces and objects when viewed under a given test source relative to when viewed under a reference illuminant. The addition of the Color Vector Graphic provides a wealth of color rendering information beyond averages, showing us at a glance exactly where the hue and saturation shifts are taking place on the color spectrum.

A Better Way to Measure Color Accuracy

With TM-30, a light source can be measured using both fidelity and gamut, together these provide the preferred or intended outcome for many designers and those considering lighting for specific areas.

The advantages of TM-30 really come into play when representing specific items or products – say, in a retail or fashion environment. A CRI score might be high, but that doesn’t mean it’s ideally suited for certain colors, in certain environments, or for the desired look & feel. This is where a vector graphic helps a user choose the right lighting for a given situation based on the colors they wish to accentuate.

While there’s no single “best” TM-30 score, you’d see near-perfect overlapping on a color vector graphic – ideal when you need to mimic natural sunlight. 

The Future of Color Rendition – the Standard?

TM-30 was introduced with the intention to provide a new way of measuring light fidelity and help users analyze the color characteristics of both modern and traditional solid-state light sources. This brings greater fairness and accuracy of the measurement.

As an improved and more comprehensive color metric, we can see its value for those who need more accurate detail to measure the color representation of several light sources.

With CRI, it seemed simple, a higher CRI score = better, more accurate color representation for a given light source. However, TM-30 provides users/designers with more information, critical to making informed decisions for the optimal light source.

At DMF, we continue to explore TM-30 results as a tool to develop new sources, further increasing options for both designers and end users, and can provide TM-30 results for any product upon request.

Focused on innovative quality – we continue to turn decades of R&D performance into the elegant luminaries of the future.

Learn more about TM-30:
Department of Energy FAQs

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The average home owner only pays attention to their recessed downlights when one goes out. The savvy home owner takes careful consideration when evaluating existing lights and planning upgrades.

At DMF, we don’t think you or anyone else should have to settle for lousy lights. In this guide, you will learn some simple visual tests to determine whether it’s time for you to upgrade your lights.

Room temperature

Color temperature can significantly influence the ambiance of a space. For example, areas that require high detail visibility, including a home office, restroom, or workshop, should utilize cooler lighting. In a living room or den, warm, yellower hues promote relaxing and entertaining.

Consistency is key

Not all LED chips are created equal. The output from two identical light sources may not match one another despite having the same listed color temperature and brightness. And the difference may appear even more apparent if the inconsistent light bulbs are installed next to each other.

Individual LEDs are extremely difficult to manufacture identically. To minimize variance, manufacturers group similar performing LEDs together in groups, or “bins”, utilizing the Standard Deviation of Color Matching (SDCM). Simply put, SDCM, or MacAdam ellipse, is a system of color measurement. The larger an LED’s SDCM, the larger the variance between LEDs within its bin, resulting in greater fluctuation in performance from fixture to fixture.

DMF only sources high quality LED from suppliers, selecting chips that have been binned by both color and brightness. This means that all our lights perform as advertised, delivering its listed lumens and CCT so you won’t see the difference from one to the next.

True colors

Have you ever noticed an object’s color appearing differently under different light? The Color Rendering Index (CRI) measures how well a light source brings out the actual colors of a surface or object being illuminated. Your downlights should exceed a minimum of 90 CRI. Low CRI lights can mute colors and wash out details, which could result in eye strain.

Beyond the light

It’s not just the light itself that matters when auditing your downlighting. The construction of the fixture and trim is critical to creating a visually pleasing, functional room.

When checking fixture quality, start by looking for light leak. Light leak occurs when recessed downlighting trims are not flush with the ceiling, creating ray patterns on the ceiling, or when the LED module produces light that escapes above the ceiling line.

Next, look at the design of the trim to determine whether or not the style matches the design of the space. Trims come in a variety of shapes and colors, and today’s buyer should not have to settle for a black cone type trim.

Finally, consider where decorative trims or hanging cylinders might better serve the style of the space. Most traditional downlight locations are also suitable for a hanging cylinder, so keep this in mind.

If you’ve found that your lights aren’t serving your space well, send us an e-mail or give us a call at 800.441.4422. We’d love to work with you.

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Properly lighting a room requires more than just picking a few bulbs to screw in. Today, lighting design lives in three distinct layers: Ambient, Task, and Accent Lighting.

LED technology has vastly expanded the forms and options available to today’s lighting designer or homeowner. Following a few simple guidelines can help ensure beautiful and effective lighting for your space. The guidelines set forth in this article draw heavily on a base knowledge of color temperature, lumens, and center beam candlepower.

The Ambient Layer

Also called General Lighting, the ambient layer provides the illumination required for occupants to see the space in its entirety. Most often, this layer is constructed through downlighting, with the initial layout set when the architectural plans are finalized.

When selecting downlights for the ambient layer, first consider delivered lumens. Larger areas or rooms with higher ceilings require more lumens to sufficiently light the space. Once the total lumens matches the size and shape of the room, space the lights for even coverage of all horizontal surfaces. Finally, the color temperature of the lights should align with the décor and purpose of the room. Bathrooms, office areas, and kitchens commonly utilize cooler color temperatures, whereas bedrooms, dens, or eating areas tend to be more warmly lit.

In the case of the ambient layer, the most logical choice is the DRD2 General Downlight, with a 78 degree beam angle and evenly distributed light. Available in four color temperatures, the DRD2 functions perfectly in the OneFrame System.

The Task Layer

Once the ambient layer sufficiently illuminates the space, use the task layer to enhance function of specific areas. In an office, this might be the desk workspace. In a kitchen, task lighting illuminates cooking surfaces or countertops.

As with the ambient layer, factors like color temperature and beam angle are also important when building the task layer. For areas where safety is important, like a cooking surface in a kitchen, a tighter beam angle and high center beam candlepower would be appropriate.

The DRD2X Apex Series Downlight is a popular choice for task lighting, as its tighter beamer angle and higher center beam candlepower make for a great spotlight over surfaces like work tables. Like the DRD2, the DRD2X integrates with the OneFrame System and all OneFrame compatible trims.

With both the ambient and task layer in place, any room should be fully functional for its intended purpose. The final layer will take the functional bases of the ambient and task layers and add artistry and style.

The Accent Layer

The accent layer adds a decorative finish by complimenting the other two layers and highlighting architectural features like columns, floral arrangements, and wall art.

This layer is the most subjective of the three but offers the most opportunity for artistic influence. A great lighting designer can use the accent layer to blend the other two and tie the space together.

The natural fit in this layer is the DRD4 Adjustable Downlight, which pivots smoothly and locks in place to perfectly illuminate the features of the room.

Unlike the ambient and task layers, the accent layer would include more artistic aspects, such as decorative trims. Specialized wall wash trims also serve to convert a traditional downlight into an accent light.

Tying it All Together

DMF Lighting offers modular downlighting to allow streamlined specification of all three layers of light via its patented OneFrame System. The award-winning OneFrame allows downstream design flexibility for lumen output, beam angle, and color temperature.

With all three layers, the room should be safe to navigate and operate in while comfortable and beautifully accented. The specification of the OneFrame System helps ensure simplicity and reliability throughout the duration of the design process, even as requirements change.

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If you’ve been keeping up with our recent articles on downlighting photometrics, you’ve already read about how the lighting industry now universally uses lumens, rather than watts, as the broadest distinguishing metric between light sources. You’ve also read that delivered lumens is a better measure of a light’s useful output than total lumens. Now, we’re going to look at another aspect that’s key to improved lighting design and fixture selection: Center Beam Candlepower.

Center Beam Candlepower (CBCP) is a measure of the luminous intensity at the center of a directional light source. Unlike most omnidirectional light sources, such as table lamps, downlights emit light from a single point, in a given direction. Depending on the beam angle, the CBCP could vary greatly, even among fixtures with the same delivered lumens.

Lumens are measured as the total light emitted from a source, at all angles from that source. For this reason, CBCP offers a more use case specific metric for determining lights in a given space.

Depending on the angle of a flood or a spot, the Center Beam Candlepower could vary greatly, even among fixtures with the same delivered lumens.

How to Shop for DMF Lighting Using CBCP

Let’s compare two DMF downlighting products, the DRD2 and DRD2X, to better understand how CBCP practically comes into play when selecting a module for your space.

The 750 Lumen DRD2 is a general downlight, with a 70° beam angle. The 750 Lumen DRD2X is a spot/flood downlight, available in 20°, 30°, or 40° beam angles. With the same trim, DRD2 has a CBCP of 518 Candelas whereas a 20° DRD2X has a CBCP of 3949! The graphic representation below shows how the distribution of the light greatly affects the CBCP.

In practical terms, this means the DRD2 would deliver the same amount of light in a wider pattern, whereas the DRD2X would deliver the same amount of light in a tighter, more concentrated beam.

To apply CBCP as you select the right lights for your space, consider the working surface and use case. For example, in a living room, you might place several DRD2s with their broad beam angle and lower CBCP to generally illuminate the entire area, but you might select the DRD2X to highlight a particular feature of the room, like a work desk, aquarium, or dining table. The DRD2X might also be preferred for spaces with higher ceilings.

Center Beam Candlepower provides another valuable metric to better inform both lighting design as well as manufacturer selection. By taking CBCP into account, you can be sure that you have the right light distribution for your application.

To learn more about other factors in choosing the right lights for your space, see these valuable companion posts:

Color Temperature
Delivered Lumens
Color Rendering Index

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People used to buy light bulbs using wattage. Today, with the expansion of LED lighting, the industry now uses lumens, a measure of the light itself, when shopping for lighting. Let’s start by exploring how watts and lumens differ.

Wattage is used to measure energy consumption and has made sense as the go-to metric for light comparison when using incandescent technology. A 100-watt bulb is brighter and consumes more power than a 60-watt bulb. LED technology allows us to produce light much more efficiently, so the industry has shifted to using lumens as the new standard.

The lumen is a unit of measure for the total quantity of light emitted by a source.

Using lumens is closer to measuring the actual brightness of a light, rather than how much energy it consumes.

Today’s lighting buyer must familiarize themselves with how lumens compare to wattage when lighting a space. Below you’ll find a table created by EnergyStar that serves as an initial guide when switching from an incandescent solution to LED.

To learn more about other factors in choosing the right lights for your space, see our primers on Delivered Lumens, or Color Temperature.

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As manufacturers shift away from watts (a unit of power) to measure light output, take note of the units advertised. While lumens are a more accurate measure, there is an important distinction between total and delivered lumens.

Total vs. Delivered

As the name suggests, total lumens measure the total light emitted from a source in all directions. This can include light emitted into the ceiling or within the fixture. Delivered lumens takes into account additional factors, such as reflection or refraction, to only measure the light in the space. The light exiting the fixture into the space (delivered lumens) can measure 20% to 50% less than the light generated (total lumens).

Delivered lumens measures how much light you are actually buying for your space, rather than how much light the module produces in a lab.

Engineered to Deliver

With each light reflection, some of the light gets lost, resulting in wasted power. At DMF Lighting, we’ve specifically designed our recessed LED downlights to maximize the delivered lumens of the light output. Our engineers include premium reflectors, diffusers, and lenses to enhance optical control. They design sleek, unobtrusive trims without dramatic cutoffs. And, they ensure all components of the luminaire work together to minimize wasted light.

When reading labels or spec sheets, it’s important to know whether you are reading total or delivered lumens. For simplicity and accuracy, DMF distinguishes between delivered and total lumens. This way, specifiers, architects, and lighting designers can properly light a space. Make sure to check spec sheets carefully to know which metric is used.

(DMF DRD2 Spec Sheet example)

If you’re struggling to pick the right lights for your space or have any questions, please send us a message.

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Today’s leading builders and customers are all moving in one direction: towards adopting LED lighting. It’s more energy efficient and easier to maintain than conventional lighting and renders color more accurately than before. And retrofitting LED lamps into existing fixtures is the fastest, most economical path.

If you’re looking to upgrade your recessed lights, here’s everything you need to know.

What is retrofit?

In general, retrofit is the process of adding a new component or accessory to an existing item. In the case of recessed downlighting, retrofit specifically refers to upgrading the lamp source, usually to a newer technology like LED, while retaining the existing above-ceiling fixture and lighting layout.

Why should I consider retrofitting recessed LED downlights?

Upgrading to LEDs not only provides highly accurate color rendering and a greater spectrum of color temperatures, it does so for less. LED technology is more energy efficient and lasts longer than traditional lamp sources like incandescent and compact fluorescent. The reduction in energy costs and maintenance can save as much as $942* over the lifetime of the LED.

Also, additional savings come from the retrofit process. Without the need for new fixtures and skilled labor, retrofitting allows you to improve your lights without remodeling the space.

What size do I need?

Before considering what new recessed light you want, first determine the size of the existing lights. Recessed downlights are offered in three traditional sizes, 4”, 5” and 6”, and the new trim must match the existing size. You cannot retrofit a different size into the current housing.

To determine the size of the existing recessed lights, the trim must first be removed. Nearly all trims utilize either coil springs, tension clips or torsion springs. Remove the old lamp and unhook or compress the springs or clips to remove the trim, then measure the diameter of the ceiling cut out to determine the size.

What specs do I need for my LED module?

LED modules offer outstanding illumination along with a host of options, including light output (lumens), warmth of color (color temperature) and color rendering accuracy (CRI). These lighting characteristics can dramatically change the look and feel of a room. Which specs work best for your application depends on the usage of the space. Be sure to consider the type of room, its usage, interior design and ceiling height when specifying LEDs.

What connector do I need?

Check your existing light source to determine which connection you have. The new LED module may not be directly compatible with the existing connector, so an adapter may be necessary. There are three common connection types. Edison screw is traditionally used for incandescent bulbs, GU24 is used by some CFL and LED lamps, and Ideal connectors are commonly found on LED modules.

What trim to pair it with?

Most recessed LED modules are engineered to work exclusively with the manufacturer’s trims, providing a better fit and additional features.

Once you’ve determined the correct size, choose the trim shape, style and finish that matches your environment. You can even angle the direction of the light with a Wall Wash Trim.

Installing your new (and improved) DMF LED downlights

Now that you have the proper LED retrofit kit (module, trim and connector), it’s time to install it. If you’re installing a DMF retrofit kit, the process couldn’t be simpler. We design and engineer our products to be easy to install without the need for tools.

1) Be sure to turn off power at the electrical service panel

2) Remove existing lamp source and trim from housing 

3) Attach appropriate connector to existing housing (Edison shown)

4) Connect DMF module to trim with Twist & Lock feature

5) Attach the green ground wire (factory installed) to the housing using existing screw inside the housing

6) Connect module IDEAL female connector to male connector

7) Snap module and trim into place using tension clips or torsion springs

8) Reconnect the module to power – and that’s it!

It’s time to flip the switch on your new recessed lights and enjoy the accurate color rendering, vivid colors and efficiency benefits of LED lighting. Feel what a difference quality lights make.

Learn more about color rendering.
Learn more about color temperature.
Watch our retrofit installation video.

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To send feedback or learn more, please contact the DMF Lighting Marketing Team.

*based on single DRD2 LED module over its lifetime, assuming 8 hr/day operation at $0.11 kWH energy rate