PRIMEX – Lighting Lexicon for LED Technology and Lighting Design


Our lighting glossary explains LED technology in simple terms. Modern LED systems are powerful, versatile, and energy-efficient. But behind every professional lighting solution lie technical specifications and terminology that are crucial for planning, design, and application. Our compact lighting glossary conveys the most important basics – practical, easy to understand, and technically sound.
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PRIMEX – Lighting lexicon for LED technology and lighting design
LED Technology Explained Simply: Modern LED systems are powerful, versatile, and energy-efficient. However, behind every professional lighting solution lie technical specifications and terminology that are crucial for planning, design, and application. Our concise lighting glossary conveys the most important basics – practical, easy to understand, and technically sound.

KELVIN (K) – Color temperature

The color temperature determines whether light is perceived as warm white (cozy) or cool white (activating).

The lower the Kelvin value, the warmer the light:

  • 2700–3000 K: Warm white – e.g., hotel, lounge, living room
  • 3500–4000 K: Neutral white – e.g., office, retail, exhibitions
  • 5000–6500 K: Cool white / daylight white – e.g., industry, medicine
  • Tunable White (2700–6500 K): Dynamically adjustable, e.g. for HCL applications

 

Luminous flux

Luminous flux refers to the light output (radiation) of a light source in all directions. The emitted light output is measured in lumens (lm).

Luminance

Luminance is the ratio of the size of the illuminated area to the luminous intensity. It is measured in candelas per unit area (cd/m²).

reflection

Reflection occurs when a light ray hits a surface and is reflected back from it.

CRI – Color Rendering Index

The CRI describes how naturally colors are rendered under a light source. Scale: 0 (poor) to 100 (daylight reference)

The lower the Kelvin value, the warmer the light:

  • CRI > 90: Very high color rendering – for showrooms, museums, and retail with colored products
  • CRI 80–89: Standard quality – e.g. for office, catering
  • CRI < 80: For industrial or outdoor areas with lower requirements

 

LUX (lx) – illuminance

LUX indicates how much light (lumens) falls on a specific area. 1 LUX = 1 lumen/m² Recommended illuminance levels according to application: Office workstation: approx. 500 lx Retail spaces: 300–750 lx Museums / Galleries: 200–300 lx (targeted) Entrance areas: 100–300 lx

Beam angle

The angle at which light is emitted from the light source is called the beam angle. It is given in degrees (°).

glare

Glare impairs vision and is perceived as a nuisance. Glare is tiring for the eyes and leads to fatigue and loss of concentration.

Light colors

Light colors influence not only our visual perception but also our emotions and feelings. By consciously choosing colors, we can deliberately shape the atmosphere of a room and thus create the desired ambiance.

Light itself is energy in the form of electromagnetic radiation that propagates in waves. The light spectrum extends from long-wave infrared rays through visible light to our eyes, all the way to short-wave ultraviolet rays.

Depending on the wavelength, we perceive different colors: red, orange, yellow, green, blue, indigo, and violet. The sum of all wavelengths results in white light; black light represents the absence of reflected light.

The associations we have with certain colors are diverse. Yellow quickly evokes thoughts of sunshine, warmth, and joie de vivre, while blue awakens memories of the sea. Red makes us think of fire and passion. Light, bluish tones create an impression of vastness, airiness, and coolness, while orange and red tones have a warm and stimulating aura.

The brightness or intensity of a color also plays a role. Dark colors make room contours visually disappear, blurring the boundaries of a space. In contrast, white lends rooms freshness, spaciousness, and clarity, conveying a feeling of openness and lightness.

Different lighting effects can be achieved by mixing colors. In lighting technology, there are two different methods for creating new light colors:

  • Additive color mixing (The primary colors red, green, blue are mixed; when the 3 colors are in equal proportions, white is produced)
  • subtractive color mixing (The primary colors yellow, magenta and cyan can absorb parts of the light spectrum)

 

Light intensity
  • Luminous intensity is a physical quantity that indicates how much light a light source emits in a particular direction.
  • It is measured in candela (cd) and depends on various factors, such as the power of the light source, the beam angle and the efficiency of the light source.
  • The brightness depends on the luminous intensity of the light source, as well as the distance to the light source and the reflective properties of the illuminated surface.
What is indirect lighting?

With indirect lighting, the light source itself is not directly visible. The light falls indirectly onto the illuminated surface through reflection or scattering. This results in a diffuse and even illumination of the room.

The advantages of indirect lighting

  • Indirect lighting has a glare-free and pleasant effect. It is particularly suitable for areas such as hotel rooms, hallways, lobbies, and restaurants.
  • The diffuse lighting creates no harsh shadows or sharp reflections, but rather soft and even light.
  • The room appears visually larger.
  • Contrasts in the room are softened and an atmospheric ambiance is created.
  • Often, the light sources of indirect lighting can be dimmed to adjust the brightness and create an individual lighting atmosphere.
  • By selecting the light color, a customized design of the room can be achieved.

What is meant by reflectance?

Reflectance indicates what percentage of light striking a surface is reflected (emitted). Reflectance depends on the surface's properties and color. Light-colored surfaces generally have a higher reflectance than dark surfaces.

  • A reflectance value of 1 means that the surface reflects all incident light.
  • A reflectance of 0 means that the surface does not reflect any light and either absorbs or transmits it completely.

Here are some examples of the reflectance of different surfaces:

  • A white ceiling or wall reflects up to 85% of the light.
  • A reflectance of 0 means that the surface does not reflect any light and either absorbs or transmits it completely.
  • Red bricks reflect up to 25%.
  • A black floor reflects no light (0%).
What does dimmable mean?

A dimmable light source allows you to regulate the intensity of the light. This is usually achieved by using a dimmer switch, which controls the current flowing to the light. Dimming the lighting can significantly influence the atmosphere of a room. Depending on mood, activity, or personal preference, the brightness of the light can be adjusted.

What are the advantages of dimmable LEDs?

  • Flexible brightness control. In restaurants and hotels, it allows adjustment to different times of day and moods. In offices, the brightness can be individually adjusted to the needs of employees, which can have a positive impact on productivity and well-being.
  • For offices or reception areas, dimming allows for the adjustment of optimal workplace lighting in accordance with the workplace regulation DIN EN 12665.
  • Dimmable LEDs contribute to extending the lifespan of the light sources. Reducing the brightness decreases heat generation, which in turn reduces the stress on the LEDs and extends their lifespan. This results in a longer service life for the light sources and lower maintenance costs.
  • Room lighting can be adjusted according to need and occasion. For a cozy evening at home, you can dim the lights to create a warm and relaxing atmosphere, while brighter lighting may be necessary for reading or working.
"Flicker effect" in film recordings of lightboxes

Primex uses low-flicker LEDs in its lightboxes. For a considerable surcharge and significantly longer delivery times, special flicker-free LEDs can be sourced and installed. In practice, these are usually only used in light sources for illuminating photographic subjects or filming.

The camera's aperture and exposure settings have a significant impact on the flickering effect in video recordings. Optimized settings can minimize flickering or, ideally, eliminate it entirely.

However, this requires appropriate expertise, as ambient lighting and other factors also have an influence.

When filming lightboxes, it is recommended not to use dimming, as experience has shown that dimming increases flickering.

Workplace lighting

The effect of light in the workplace

A work atmosphere conducive to concentration and increased well-being

Well-designed workplace lighting has a positive impact on employee health and performance. Light directly influences our mood, concentration, and productivity.

Therefore, you should consider several key factors when designing workplaces: Brightness and color temperature: A bright, neutral white (3,300–5,300 K) to cool white (> 5,300 K) light color is particularly recommended. Bright light has a stimulating effect and inhibits the production of the sleep hormone melatonin. Instead, bright light promotes alertness and concentration. It is also advisable to include daylight in the lighting, as it acts as a natural energy booster and has a positive effect on mood.

A mixture of direct and indirect lighting: Indirect lighting creates an even illumination of the room and reduces shadows, while direct lighting of the work surface provides targeted light for specific tasks.

Avoiding reflections and glare:: Avoid reflections on screens and other reflective surfaces, as they impair vision and disrupt concentration. Using glare-free lighting and carefully positioning the lights can effectively minimize this problem.

Consideration of age and eyesight: The age of employees should be taken into account when designing workplace lighting. While 500 lux is sufficient for younger employees, the lighting requirement for older employees increases to 750 to 1,500 lux to prevent eye strain.

Legal regulations and standards:

The standard DIN EN 12665 (ArbStättV) contains guidelines for workplace lighting. It establishes criteria for a safe and healthy working environment, such as...

Illuminance, uniformity and glare control.

The effects of inadequate workplace lighting can be serious. Poor lighting can negatively impact the health and performance of employees, thereby increasing error rates and the risk of accidents.

HCL

Human Centric Lighting

Human Centric Lighting (HCL) focuses on the effects of lighting on humans. It includes not only visible light but also ultraviolet and infrared radiation, which can trigger biological reactions in the body. Humans typically regulate their circadian rhythms around the sun. The so-called internal clock synchronizes with the presence or absence of sunlight. However, as our lifestyles increasingly change, it becomes more and more difficult for the body to maintain this balance.

Human Centric Lighting can be divided into 4 different categories:

Circadian lighting: Determined by the change of day and night and the seasons.

Activating lighting: It serves to increase attention and activity.

Relaxing lighting: Promotes relaxation and recovery.

Emotionally appealing lighting: It creates certain emotional moods.

What are the advantages of the HCL concept for interior lighting?

  • Strengthens and supports the natural biorhythm.
  • Can prevent sleep disorders
  • It promotes well-being, strengthens the immune system and thus health.
  • Improves concentration and performance
  • It increases quality of life and vitality
Light in old age

Vision and orientation in old age

To meet the needs of older people, it is advisable to increase the lighting levels in the home. Experts recommend twice the lighting level for seniors as for younger people to achieve the same perceived brightness. The lighting level should be increased by at least one-third above the usual standard values of 300 to 500 lux.

  • Lighting for seniors should always come from multiple sources. This ensures pleasant and balanced illumination and an even distribution of light throughout the room.
  • This reduces shadows and dark corners and prevents glare. The light can be directed so that it does not shine directly into the users' eyes, which improves vision and reduces discomfort caused by excessively bright light.
  • A mix of ceiling lights, skylights, wall lamps, floor lamps or table lamps is suitable for a pleasant and functional environment.
  • The even and contrast-free illumination of the rooms ensures better orientation for the elderly and prevents falls.
  • Due to the natural fluctuations in daylight and seasonal variations, interior lighting should be dimmable to flexibly compensate for insufficient daylight. Dimming the lights can also create a cozier atmosphere in the evenings.
Melanopic efficacy of light

Light affects us in a variety of ways: visually, emotionally, and biologically. The melanopic effect refers to the non-visual physiological effect of light on humans. The term comes from the hormone melanopsin, which makes people sleepy. Light can stimulate or suppress the production of this hormone; this process is then called the melanopic effect of light. Even in earlier times, people's lives were governed by daylight. Today, light still determines the human sleep-wake cycle and can be influenced thanks to new technologies. However, it is not the visual aspects of light that control our circadian rhythm.

The retinal ganglion cells of the eye Researchers have discovered light-sensitive ganglion cells in the human retina. These receptors process exclusively non-visual, biological stimuli from light. Among other things, the ganglion cells are responsible for the release of the hormone melanopsin and thus determine the circadian rhythm (24-hour rhythm).

The dynamics of the time of day should also be replicated in artificial lighting control. A high proportion of blue light suppresses the release of melanopsin, thus promoting concentration and increasing performance. A red light component, on the other hand, increases the release of melanopsin and thus relaxes the body.

Spatial distribution of light The direction and spatial distribution of light also affect our circadian rhythm, as the melanopic effect depends on the angle of incidence of the light. The retinal ganglion cells are located in the lower posterior region of the retina, which is why light should reach our eye diffusely from the upper hemisphere. This is also related to the natural light of the daytime sky. Large illuminated surfaces, such as light ceilings that resemble the celestial sphere, achieve particularly good biological effects.

Effects of light on age With increasing age, not only does eyesight deteriorate, but less light also enters the room through the smaller pupils. For this reason, older people need more light than younger people. To achieve a melanopic effect in older people, almost four times more light is required than in a young person. The importance of proper lighting design is enormous for stabilizing and strengthening the body's internal clock and the associated sleep-wake cycle. By considering melanopic light, concentration, regeneration, mood, and emotions can be promoted and regulated.

PRIMEX – Expertise in lighting technology

  • Experience & manufacturing expertise: Development and production in Germany – complemented by production partners in Europe and Asia for customized project solutions.
  • Sustainable production: Recycled aluminum profiles, water-based printing technology, resource-saving processes
  • Flexibility & special solutions: From single frames to curved formats to complex luminous ceilings or special constructions
  • Comprehensive service: consulting, planning, construction and logistics from a single source

Light is a design element – PRIMEX makes it precisely usable. Whether retail, trade fairs, architecture or special construction – we deliver the lighting solution that works.

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