We’re in the transition to a new generation of lighting_LED lighting. With the advance of technology, LED is toning up on its reliability for different brands and the cost is going down tremendously. Thus, it facilities the wide using of the LED lighting to save energy and reduce the carbon emission. The major and widely used LED chips brands are Cree(now Cree-LED), Osram, Samsung, Bridgelux and other joint ventures with these brands.

Unlike traditional halogen or incandescent lamps, now we use lumens as a basic criteria to determine a lamp. As the efficacy of LED lamps is far more higher than halogen or incandescent lamps, instead focusing on watts we shall eye on the lumens when we choosing a suitable lamp for a certain lighting project.

LED lighting products also produce tremendous heat as they're working. Overheat will bring damage LED and cause high lumen loss. As there is hurt to LED drivers due to overheat, electrical components will become unstable and result in problems of flicker, color shift, electrical component failures. Thus, as the commence of product development, overheat issue needs to be taken into consideration electrically and structurally.

CCT: Typical CCTs are 2700K, 3000K. But there're special needs for 2200K, 4000K, 5700K

RGBW: RGBW refers to RGB color changing and warm white. A RGBW lamp is using RGBW LED chipset and delivers manifold lighting: RGB color changing and 2700K or 3000K warm white Kelvin temperature.

RGBCW: RGBCW refers to RGB color changing and CCT tunable. A RGBCW lamp is utilizing a RGBCW LED chipset and has functions of RGB color changing and CCT tunable let's say from 2200K to 5000K tunable.

RGBW and RGBCW LED chipsets are generally used in smart lighting products(IR, WIFI, BLE enabled)

In an effort to reduce the inventory cost, the concept of beam angle adjustable LED lighting products is came up.In a lamp, by twisting the optic, you will get different beam angles.When we have different combinations of watts, cct, beam angles, distributors will need to buy a large qty of lamps to stock. If we have one lamp with watts/cct/beam angles adjustable feature, then we can save tremendous money on inventory.

Smart LED lighting refers to those with Bluetooth,WIFI,RF,IR,PLC enabled lighting products; perform with RGB changing/White color tunable or the combination of RGB changing and white color tunable. Smart LED lighting is often controlled by App on smart devices or remotes. It also connects to internet and realize long-distant control. Owing to the poor transmission of 2.4G signal underwater, we generally use PLC enabled smart lighting products for underwater applications.

There're too many different smart products with assorted control platforms in the market. For users, they have to endure the hassle to download different Apps or use different remote controllers. For a distributors, it makes no sense for them to carry different platforms. However, they will need diversified smart products from different vendors. If there's a protocol can break through different platform, it will save use hassles and simply use one platform to control all smart products. Thus, Matter comes into being. Matter is a new global, open-source standard that aims to simplify the smart home ecosystem by allowing internet-connected devices from different manufacturers to simply and securely communicate. This represents an important collaboration between competing companies working towards a common goal: to advance the smart home and make it more consumer-friendly. Until now, Matter has been a buzzword and nebulous vendor promises, but we're finally starting to see some real movement.   

Version 1.0 of the Matter smart home standard and certification program officially launched in October. In the month since its release, 190 hardware and software products have received certification (or are in the process of being verified) according to(Opens in a new window) the Connectivity Standard Alliance (CSA), the nonprofit that oversees the standard. That includes door locks, gateways, lighting, motion blinds, occupancy sensors, smart plugs, weather devices, platform components, and software applications.

What is full spectrum light? Full spectrum is not directly visible or observable

Contributing to the confusion among consumers is the fact that the "fullness" of a light spectrum is not directly observable to the human eye. In other words, a non-full spectrum bulb and natural daylight could have the exact same emitted light color and appearance, despite having significantly different spectral properties.

Full spectrum typically refers to the completeness of a light source's spectral energy, particularly when compared to natural light sources such as natural daylight. The exact spectral composition of a light source can only be determined by specialized photometric equipment, such as a spectrometer.

In other words, as a consumer, you have no practical way to independently verify or confirm that a full spectrum bulb you purchased actually has a complete spectrum.

How can that be?

Spectral speaking, there are many ways to create the same light color, and this also holds true for the color of natural daylight (commonly called daylight white).

For starters, let's take a look at the light spectrum for natural daylight. You will notice that the light energy is distributed evenly across the entire visible spectrum, without any gaps, dips, or spikes. Next, we take a look at the light spectrum for a daylight fluorescent lamp. Notice that despite its daylight color rating and emitted light color, the spectrum is very different from natural daylight. Specifically, there are numerous spikes and "valleys" as well as very little light energy emitted in the red wavelengths. What is very important to remember is that both natural daylight and this fluorescent lamp have the same apparent light color - daylight white. In other words, despite a significant spectral difference, the light color emitted from the fluorescent lamp is indistinguishable from daylight, to our eyes.

 If the color is indistinguishable, then what's the point of full spectrum light?

Broadly speaking, full spectrum light has two primary benefits:

1) Improved color rendition

Color rendition is concerned with the way objects' colors appear under the light source. In our example above with the daylight white fluorescent lamp, even though the emitted light color (daylight white) matches that of natural daylight, the fluorescent light shining onto a red apple, for example, would appear very different compared to natural daylight.

The reason is that objects' colors are determined by the wavelengths they reflect. Since the fluorescent lamp lacks red colors in its spectrum, there is a lack of red light energy reflecting off of the apple, giving it a dull red color instead.

As such, full spectrum light sources are indispensable for applications requiring accurate or consistent color appearance. For example, workers in artwork, photography and graphic arts all require full spectrum light sources so that inaccuracies in color perceptions do not hinder their work.

2) Improved health or biological benefits

The health benefits of full spectrum lighting are not directly related to the way we see light or color. Instead, it relates to other biological processes, such as the way pigments and hormones such as melanopsin in the human body react to various wavelengths and intensities of light. These processes are not directly related to the vision system, but instead provide signals to our bodies to promote alertness, sleepiness and regulate our overall moods.

These processes are not limited to humans. Plants, who also rely on light energy, will also react to different light spectra differently. Depending on the spectrum of a light source, a plant may perform photosynthesis more efficiently, or promote flowering or fruit production over vegetative growth.

Full spectrum light attempts to mitigate the effects of lacking natural daylight exposure. Artificial light sources will inevitably fall short of 100% replicating natural daylight, but the degree to which a full spectrum light source comes close to natural daylight plays a significant role in determining its effectiveness.

Color Rendering Index (CRI) is an often misunderstood metric of color quality. Yet, for any application where color appearance is important, CRI consideration is critical.

We've developed the following guide to help you understand what it is and how it can help you improve your quality of light.

What is the Color Rendering Index (CRI)?

Put simply, the Color Rendering Index (CRI) measures the ability of a light source to accurately reproduce the colors of the object it illuminates.

This is a seemingly simple definition, but there is a lot going on, so we'll help break it down into three parts

Part 1: Color Rendering Index (CRI) is a score with a maximum of 100

What does it mean to measure the ability of something? Like test scores, CRI is measured on a scale where a higher number represents higher ability, with 100 being the highest.

CRI is a convenient metric because it is represented as a single, quantified number.

CRI values that are 90 and above are considered excellent, while scores below 80 are generally considered poor. (More on this below).

Part 2: Color Rendering Index (CRI) is used to measure artificial, white light sources

Light sources can be grouped into either artificial or natural light sources.

In most situations, we are concerned about the color quality of artificial forms of lighting, such as LED and fluorescent lamps.

This is compared to a daylight or sunlight - a natural light source.

Part 3: Color Rendering Index (CRI) measures and compares the reflected color of an object under artificial lighting

First, a quick refresher on how color works.

Natural light such as sunlight is a combination of all the colors of the visible spectrum. The color of sunlight itself is white, but the color of an object under the sun is determined by the colors that it reflects.

A red apple, for example, appears red because it absorbs all colors of the spectrum except red, which it reflects.

When we use an artificial light source such as an LED lamp, we are attempting to "reproduce" the colors of natural daylight such that objects appear the same as they do under natural daylight.

Sometimes, the reproduced color will appear quite similar, other times quite different. It is this similarity that CRI measures.As you can see in our example above, our artificial light source (an LED lamp with 5000K CCT) does not reproduce the same redness in a red apple as natural daylight (also 5000K CCT).

But notice that the LED lamp and natural daylight have the same 5000K color. This means that the color of light is the same, but the objects still appear different. How could this be?

If you take a look at our graphic above, you will see that our LED lamp has a different spectral composition compared to natural daylight, even though it is the same 5000K white color.

In particular, our LED lamp is lacking in red. When this light bounces off of the red apple, there is no red light to reflect.

As a result, the red apple no longer has the same vibrant red appearance that it had under natural daylight.

CRI attempts characterize this phenomenon by measuring the general accuracy of a variety of objects' colors when illuminated under a light source.

CRI is invisible until you shine it on an object
As we mentioned above, the same light color can have a different spectral composition.
Therefore, you cannot judge a light source's CRI by simply looking at the color of the light.
It will only become evident when you shine the light onto a variety of objects that have different color.

How is CRI measured?
The method for calculating CRI is very similar to the visual assessment example given above, but is done via algorithmic calculations once the spectrum of the light source in question is measured.
The color temperature for the light source in question must first be determined. This can be calculated from spectral measurements.
The color temperature of the light source must be determed so that we can select the appropriate daylight spectrum to use for comparison.
Then, the light source in question will be virtually shone onto a series of virtual color swatches called test color samples (TCS) with the reflected color measured.
There are a total of 15 color swatches:We will also have ready the series of virtual reflected color measurements for natural daylight of the same color temperature.
Finally, we compare the reflected colors and formulaically determine the "R" score for each color swatch.The R value for a particular color indicates the ability of a light source to faithfully render that particular color.
Therefore, to characterize the overall color rendering capability of a light source across a variety of colors, the CRI formula takes an average of the R values.

When comparing lighting products, you will undoubtedly come across the metrics CRI and Ra to describe color quality. You may assume that there is no difference between CRI vs Ra, but read on to find out how this could be a mistake!

CRI defined

CRI is an acronym for Color Rendering Index, and is the world's most widely accepted metric to describe a light source's ability to accurately reproduce color.

The general concept involves using a set of 15 predefined colors called test color samples (TCS) and determining how accurate a light source would make each of these colors appear.

"Accurate" is defined as similarity to natural daylight or an incandescent bulb, depending on its color temperature. (This is a bit of a simplification - for detail, see here).

Each of these TCS scores is called Ri, where R stands for Rendering Score, and i is the TCS index number. For example, the score for TCS4 ("Moderate yellowish green") would be calculated and labeled as R4. Once each of the R values is calculated, two types of CRI, called General CRI and Extended CRI, can be calculated.

General CRI

General CRI is calculated as the average value of R1 through R8. Formulaically, this is often referred to as Ra, where a is an abbreviation for "average."

Note that only R1 through R8 are used, and R9-R15 are NOT used in the calculation of Ra.

Extended CRI

Extended CRI is calculated as the average value of R1 through R14. Sometimes the symbol "Re" is used, where the letter "e" represents "extended."

Notably, extended CRI captures the influence of saturated colors such as deep red (R9) and strong blue (R12) that general CRI does not.

This is one of the criticisms of the general CRI, and it is therefore always a good idea to look at extended CRI and the specific R values when working on a project where color quality matters.

What is Ra?

Technically, Ra is just a symbol in the formulae for general CRI calculations, but has become widely used as a synonym for general CRI.

In other words, Ra is also the average value of R1 through R8.

Lost in translation?

In the United States, the term CRI is used to refer to general CRI (R1-R8), while this is not necessarily the case in other regions of the world. In China and Europe, for example, CRI is typically used to describe extended CRI (R1-R14).

Depending on who you are speaking to, CRI can take on a very different meaning.

Our recommendation is to be explicit when discussing these metrics with manufacturers and customers. When discussing general CRI, it is best to use the term "CRI (Ra)" or general CRI (R1-R8). When discussing extended CRI, use the term "CRI (e)", "Re" or extended CRI (R1-R14).

Typically, extended CRI is used less frequently than general CRI, but when in doubt, it is always best to clarify!

CRI R9 is one of the test color samples (TCS) used in the calculation of extended CRI. Many manufacturers will only report general CRI, however, which does not include the CRI R9 score. (See CRI extended vs CRI general). CRI R9 is therefore oftentimes a useful supplemental score to judge a light source's color rendering ability, specifically as it concerns objects whose reflectance spectra contain red wavelengths.

A closer look at how R9 is calculated, along with  its corresponding test color sample (TCS9) is a common recommendation for anyone who needs to know about a light source's color quality.

What is CRI R9?

R9 is the score that represents how accurately a light source will reproduce strong red colors.

"Accurate" is defined as similarity to daylight or incandescent bulbs, depending on the color temperature.Just like each of the CRI R value calculations, R9 is calculated by calculating the reflected color from a theoretical object with the reflectance profile defined as TCS9. 

What is notable is that the TCS9 spectrum is almost entirely composed of red light. Spectrum-wise, we see this as wavelengths longer than 600 nm.

This means that if there is not enough red light in the light source, it will make red colors appear "off" or different.

As a result, the CRI R9 value for this LED is at -1.4. (That's right, a negative number!) This is in spite of the fact that the general CRI (Ra) comes in at 79.

Why is CRI R9 important?

CRI R9 is a very important metric because many light sources will be lacking in red content, but this fact will be hidden due to the averaging out of CRI calculations which do not include R9.

A closer look at the R9 value, however, reveals that the light will perform very poorly for red colors in particular.

What is a good CRI R9 value?

Although the maximum possible value of R9 is also 100, unlike average CRI numbers, R9 should be judged a bit differently.

Mathematically, R9 is far more difficult to achieve a high score compared to the other R values that comprise the CRI calculations, and is far more sensitive to spectral variations. Therefore, an R9 score of 50 or above would be considered "good" while an R9 score of 90 or above would be considered "excellent."

You will therefore find that most lighting products available in the market will rarely specify the R9 value, and when they do, rarely will they guarantee anything higher than 50. Even at Waveform Lighting, we specify R9 > 80 or R9 > 90, and are unable to guarantee anything higher than R9 > 95 due to this sensitivity.

This is due to the fact that CRI utilizes the CIE 1960 uv color space, which is skewed in a way that exaggerates color differences in the red region of the chromaticity diagram. Since CRI is a calculation that quantifies color differences between a light source and a reference source, a larger calculated color difference will result in a larger decrease in the R score.

Why is red such an important color?

Red is a crucial color for many applications including photography, textiles and reproduction of human skin tones.

Many objects that do not appear red actually are a combination of colors, including red. Skin tones, for example, are very much influenced by the redness of the blood that flows right beneath our skin.

Therefore, a light that lacks red will make a person look pale, or even green. This can be problematic for medical applications where color appearance is critical for accurate diagnoses. In other applications such as photography, aesthetic appearance is crucial and many times cannot be corrected for even in post production and digital editing.

When searching for a high color quality LED, be sure to inquire about the CRI as well as its R9 value.