Lumistrips LED Lighting Blog

Recommended color rendering index CRI base on your project

The CRI, colour rendering index, is a one-number quantification that indicates the performance of an artificial light source in terms of colour rendering compared to a reference standard light source modelled on daylight. The highest number is 100, for daylight and incandescent/halogen lamps, while gas discharge lamps range from 17 to 96, with even a negative value for low sodium pressure (the yellow type used in street lamps).

Due to this variation in the ability to reproduce colour with the white light emitted by the many types of gas lamps on the market, CRI index was introduced in 1974 by the International Commission on Illumination (CIE). 

Today, with more than 40 years of use, the CRI index is firmly rooted in the lighting industry and among professionals. However, it has not been very well understood by the public. The reason was that such knowledge was not really useful as most lamps were built for specific applications that required a minimum CRI value, so one could not go wrong when choosing a lamp.

For example, for office or other linear lighting, the lamps of choice where Tri-Phospor linear fluorescent tubes on the market since the 1970s, all with a CRI value above 80. For domestic lighting, there was a mix between incandescent and halogen lamps, both with CRI100, for retail and other high intensity spot lighting, metal halide lamps with CRI min 85. Street lighting was reserved for high intensity and very efficient sodium vapour lamps, which had a poor CRI but this was considered not important.

From the year 2000 this changed with LED technology, the first light source that can be used for any application while having a broad performance and quality level, including the ability to reproduce colours accurately. It is therefore essential that you choose LEDs with the right CRI level for your application.

CRI comparison

The picture above shows how colors can look different based on the CRI of the light source that illuminates them. A vibrant red under sunlight or a high CRI light can look dull or even orange under a low CRI light.

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Tips on how to build the best lines of light or linear light fixtures with LED strips

Lines of light are a new trend in lighting design and are usually made with an LED strip inside an aluminum profile that has a translucent white cover. The attraction of using such a linear light fixture is that it can be personalized. You can choose as you desire the pattern, place of installation, length (up to many meters), geometric shape or a combination of these elements.  

Line of Light with LED strip inside a profileBecause of their way of construction lines of light are a type of direct lighting. Compared with coves that are indirect lighting, lines of light are more energy efficient but can have greatly increased glare. For this reason lines of light should be designed with care and almost always be dimmable. 

Let's see how we can achieve the best results with lines of light.

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Tips on how to have the best illuminated stretch ceiling with LED modules

The illuminated ceiling or stretch ceiling is very interesting trend in interior lighting. By using a translucent material many square meters in size with a backlighting system, a diffuse, even and relaxing illumination of interiors can be created. The main advantage of this type of lighting is the absence of glare, as the light sources are distributed over a large area and hidden behind the material.

The backlight source is usually low or medium brightness LEDs (5 to 50 lumens) mounted on strips or modules. Since the illuminated surface has a large area, such low power illumination is the best choice.

Illuminated stretch ceiling with LEDs, inside an office

Illuminated stretch ceilings can have personalized shapes and even feature translucent images. They can therefore influence the overall design of a room much more than other lighting fixtures. From a lighting design perspective, uniform light should be supplemented by spotlights or lamps that can draw attention to specific areas or objects.

The proper design and installation of a luminous ceiling has a number of unique challenges that we will address in this article.

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Cove lighting with LED strips: HOW TO

A Cove light is a line of light can obtained via a LED strip hidden from view inside a cove in the wall or ceiling that illuminates an adjacent surface. Light is reflected from this surface into the space that has to be illuminated. That is why lines of light are commonly known as cove or indirect lighting.

Cove lighting is beneficial trend to design lighting, with focus on human nature and how natural light behaves. It is today widely adopted, with lines of light as a principal way to illuminate interiors.

The allure is the similarity with natural light. With the proper light source used, we could imagine that the cove is actually a hidden window to the outside from where sunlight flows in.

Lets explore how we can have the best results with cove lighting

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What does IP wateproof rating means and what value are recommended IP levels for the bathroom

WHAT DOES IP PROTECTION MEAN?

The IP protection index is an essential feature of most electrical equipments and indicates the degree of protection of the device against external factors such as solid objects or liquids. This protection is expressed by the word "IP", followed by 2 numbers that indicate

  • The first digit describes the degree of protection against solid objects, dust, solid particles and bodies
  • The second digit describes the degree of protection against liquids

The IP rating is relevant when the environmental conditions are standard; in special cases and hazardous environments, special protection is required.


Although there are numerous combinations of IP ratings for LED strips, the most common are IP67, IP65, IP44, IP20. In general, all LED strips have IP20 protection,  IP44 can be found for LED strips within an aluminium profile with closed end caps and IP65 or more is normally used for waterproof LED strips.

The first digit – protection from foreign bodies

  • 0 – no protection from foreign bodies;
  • 1 – protected against solid objects greater than 50mm(e.g. accidental touch by hands);
  • 2 – protected against solid objects up to 12mm(e.g. fingers);
  • 3 – protected against solid objects greater than 2.5mm(e.g. tools and wires);
  • 4 – protected against solid objects greater than 1mm(e.g. small tools and wires);
  • 5 – protected against dust, limited ingress(e.g. no harmful deposit);
  • 6 – totally protected against dust.

The second digit – protection from liquids

  • 0 – no protection from liquids;
  • 1 – protection against vertically falling drops of water(e.g. condensation);
  • 2 – protection against direct sprays of water up to 15 degrees from vertical;
  • 3 – protection against direct sprays of water up to 60 degrees from vertical;
  • 4 – protection against water sprayed from all directions – limited ingress permitted;
  • 5 – protected against low pressure jets of water from all directions – limited ingress permitted;
  • 6 – protected against high pressure jets of water (use on ship deck) – limited ingress permitted;
  • 7 – protected against the effects of immersion between 15cm and 1m;
  • 8 – protected against long periods of immersion under pressure.

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Seoul SunLike LEDs improve sleep patterns ease eye strain, two research studies find

Seoul SunLike LEDs ease eye strain and improve sleep patterns, two research studies suggest

The positive health effects of the full spectrum SunLike LEDs from Seoul Semiconductor have been confirmed in two independent studies, by universities from Switzerland and South Korea.

The new SunLike LED technology brings a major improvement to the spectral power distribution (SPD) of LED lights, which now mimic the SPD of the sun within the bounds of the human visual range. The SunLike LEDs use a three-phosphor mix and a violet emitter to achieve the SPD. Seoul has said that the LEDs can be used in a variety of applications including in human-centric lighting or lighting for health and well-being where tunable lighting can be applied to improve human well-being.

SunLike LED Desgin 

A study published by the University of Basel in Switzerland titled “Effect of daylight LED on visual comfort, melatonin, mood, waking performance, and sleep” found that volunteers had better visual comfort, more alertness, and happier moods associated with exposure to SunLike LEDs compared to other LEDs. 

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Nichia Optisolis LEDs light art museums across Germany

The innovative Optisolis LEDs from Nichia natural spectrum LEDs that emit light which closely matches the spectrum of natural sunlight.

The extraordinary result is achieved by using a revolutionary new phosphor technology and special blue LED chip. The spectrum of the 420nm blue chip contains almost no UV emissions and in combination with the phosphor achieves a CRI value of 98+, an ultrahigh number considering sunlight has CRI 100.

The high quality of light from Nichia Optisolis LEDs renders colors accurately and adds the benefit of increased awareness of contrast and texture. In combination with their very low UV emissions, Optisolis light fixtures are particularly suitable for use in museums and art galleries where the highest possible CRI value is preferred without damaging the valuable works of art with UV rays.

The first to implement Nichia Optisolis lighting are museums in Germany: Zeppelin Museum in Friedrichshafen, the Ludwig Museum in Koblenz and the Picasso Museum in Münster.

Zeppelin Museum Friedrichshafen: LED lighting (left) and Optisolis LEDs by Nichia / Lumitronix (right)

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Seoul Semiconductor SunLike Natural Spectrum LEDs reveal color and depth of artistic works

The new SunLike LEDs from Seoul Semiconductor are the world’s first natural spectrum LEDs, as they produce light that closely matches the spectrum of natural sunlight. This is made possible by using a the TRI-R technology new LED architecture, with a purple emitter in combination with a red, green, and blue (RGB) phosphor mix, unlike conventional white LED that use a blue emitter and yellow phosphor. 

Spectra comparison Sunlike LEDs, sunlight, ordinary LEDs, fluorescent light

This new design makes possible for an LED to render colors very accurately, almost as sunlight, with the added benefits of increased awareness of contrast and texture.

Sunlike LEDs will make art have the same colors and contrast as under sunlight


The high quality of the SunLike LEDs light spectrum is expressed both by the traditional color rendering index (CRI) and the new Color Fidelity Index. Therefore, SunLike LEDs have CRI 97+ and  Rf 96(TM30 Fidelity Index), values that indicate the high accuracy of reproducing the original color from 99 representative color indexes.

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Innovative LED technology: SunLike Natural Spectrum LEDs by Seoul Semiconductor

SunLike LED techology from Seoul Semiconductor and Toshiba

The innovative SunLike LEDs from Seoul Semiconductor are the first natural spectrum LEDs on the global market. For the first time an LED can emit light that closely matches the spectrum of natural sunlight.

SunLike LED package design


The special ability to have a spectrum close to sunlight comes from using a new LED design, with a purple emitter in combination with a red, green, and blue (RGB) phosphor mix, unlike conventional white LED that use a blue emitter and yellow phosphor.  By removing the blue LED chip and replacing it with a purple light one, lighting technology is fundamentally transformed. For the first time it is possible to render colors accurately with very low energy use and positive effects on health. Compared with other LED lights, the new SunLike Series do not have a blue energy peak associated with eye discomfort and poor sleep patterns.

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Casambi light control and Seoul Semiconductor SunLike LEDs for true human-centric lighting

SunLike Human Centric lighting via Casambi app

Casambi, a pioneer in Bluetooth Low Energy (BLE) wireless lighting control, has teamed up with LED technology specialist Seoul Semiconductor to offer lighting designers precise control of LED strips, modules and luminaires that use the new SunLike technology that matches the spectrum of sunlight. For the first time, this development puts true human-centered lighting in the hands of designers.

Users can use Casambi's Bluetooth-based wireless control system and app with products that include SunLike series LEDs to precisely adjust the light level, knowing that the spectrum reflects real sunlight, a key ingredient for Human-centric lighting

Human-centric lighting describes lighting designed to work with the natural rhythms of the human body. It is based on the well-known fact that the human eye recognizes the presence of a certain wavelength of blue light in the spectrum of sunlight and derives the time of day from this. In this way, light helps to regulate our sleep-wake cycles and other physical rhythms and has a significant impact on our mood and well-being.

Human-centered lighting takes advantage of this effect by adjusting its brightness and color temperature during the day to mimic natural light.

With Casambi you can now set the color temperature at specific hours of the dayCasambi allows control of the lights through a timer or a variety of presence/movement sensors and daylight sensors. It can control lights that change colour temperature over a very wide range, and designers have the freedom to configure dimming and create scenes or animations for the application.

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