The formal word for the flaw-filled, damaged, distorted appearance of the eye’s lens. It occurs when light does not meet all the same optical specifications when it passes through the lens, like a compromised camera lens or a water-stained window.

The absorbance value of the material is how much it keeps in. Higher absorbance value means that the material keeps more light in

Sometimes people want to be the center of attention, so they put special lights on themselves or their space and objects

It's like a camera. Its lens changes, and that makes it possible to see a very nearby object as well as a faraway one.

The eye is able to change its sensitivity over a wide range and adjust to different levels of light. This is achieved by contracting or dilating the pupils, and also by adapting the sensitivity of the retina's rods and cones.

Attaches spotlight or floodlight to track, mechanicaly and electrically

Additive colour mixing is a form of color mixing that produces light. In additive colour mixing, unlike subtractive color mixing, one adds colours together in order to make new colors. By mixing the three primary colors of light in equal amounts, one produces white light.

Ambient light creates the right ambiance for your home. The right light, in a smart way gives you more comfort, safety and well-being.

Ambient lighting is all about creating a cohesive look throughout your home, so you can have a restful night's sleep and wake up feeling refreshed.

The angle from which an object is viewed, measured in degrees.

This highly desirable surface coating is extremely durable and has high (luminous) reflectance. It’s basically an electric-powered way to make things shiny.

Anti-dazzle cap is an attachment for controlling the light from the lamp in the main direction of the beam. The beam is restricted and/or prevented completely.

Anti-dazzle attachment to improve visual comfort. The cross baffle partially conceals the reflector and the lamp.

Lighting systems that require special attention to design and engineering. The resulting light is not just decorative but functional; designed in conjunction with the architectural design.

A B Corp is a for-profit company with a societal or environmental mission at the core of its DNA.

Ballast is the term used to describe electrical devices that control the flow of current in discharge lamps. A ballast can be an inductive, electronic or magnetic device. It limits the current going through the lamp and improves lamp life by reducing wattage wastage. Ballasts may come with an ignitor or starting device for inefficient lighting.

Term used to describe rectangular anti-dazzle screens used predominantly with stage projectors

Light intensity distribution curve of a luminaire with especially wide-angled light intensity distribution characteristics. The name is derived from the batwing shape of the light intensity distribution curve.

Lighting concepts for the biological needs must meet several basic human needs to be effective. Specifically, lighting concepts for the biological needs need to provide enough light so that people can see what they are doing. This allows them to perform tasks correctly and safely, provides spatial orientation, reduces accidents and supports personal growth by allowing for good performance.

Bollards are lights that you see in the sidewalk on a street to give light to the ground.

The brilliance effect produces a rich, sparkling shine on glossy surfaces or transparent materials. Brilliance is produced by the reflection of the light source or the light being refracted; it is produced by compact, point light sources.

A unit of light intensity that is universally used to measure the brightness of a light source. 1 Candela is equal to one candle measured at a distance of 1 m.

It means to do things that don't make the air dirty. This includes burning wood instead of coal, and planting trees to clean the air.

You can use Casambi to control lights when you're at home or away.

The central field of vision is the part of your visual field that you can see straight ahead without moving your eyes. This area is used in your everyday life and it has the same significance as a working plane since you use it in day-to-day tasks such as driving, writing and reading. The peripheral or surrounding field is everything that lies outside of the central field of vision.

Circadian lighting sends signals to the master clock in the brain, telling our bodies when it is daytime and when it is night.

A Circular Economy is a new way to do business that helps the planet by reusing things rather than throwing them away.

Light adaptation is a feature of ocular physiology that allows the retina to adjust to a wide range of luminous colors. This adjustment allows us to see vaguely illuminated objects fairly well, even in the absence of light.

LED light bulbs can change color. They come in different shapes and sizes, and you can use them with smart technology things.

Humans perceive color because of the varying sensitivity of light receptors in the retina to different wavelengths of light.

The colour rendering index Ra is the dimensionless quantity that describes the quality of colour rendering. The higher the number is, the better the light source is able to reproduce colours.

CRI means colors look better under some lights than others. It's what people used to use to decide which kind of lightbulb to buy.

The colour spectrum is the collection of colours of different wave lengths that are produced when light is dispersed by a prism. The place where the most intense peaks occur in this spectrum is known as the spectrum band.

The colour temperature of a light source is a measure of the colour of its light. Described in degrees Kelvin, this informs you how much "warming" or "cooling" effect a light source will have on objects, people and your surroundings.

Low power factor of discharge lamps combined with the inductive ballasts leads to a large amount of current which does not contribute to light output and is therefore called blind current. Power supply companies require the use of power factor correction capacitors to compensate this effect. The costs involved in these additional components must be taken into consideration when choosing an induction ballast.

The ability to distinguish the constant qualities of objects from changes in the environment, such as distance, position within space and lighting.

Without constant current LED power supplies, a lot of LEDs can't work well.

Difference in the luminance or colour of two objects or one object and its surroundings. The lower the contrast level, the more difficult the visual task

The contrast rendition factor is the ratio of luminance contrast of the visual task under given lighting conditions to that under reference lighting conditions.

Control gear is where it all happens. It's the equipment required in addition to the actual light source for its operation. Ballasts, ignitors and transformers are typical examples of control gear.

Convergence describes the alignment of the optical axes of the eyes to an object. In normal vision your eyes are converged when looking at objects at a distance similar to that of houses in the background, meeting at an angle when looking at something right in front of you like a computer monitor or face.

Cool beam reflectors are made from highly polished aluminum, or glass coated on one side with dichroic material. This can either be infrared reflective, or transparent to visible light and shiny on the backside. As a result, the heat generated by light is reflected away from the object and toward the ceiling.

Architectural element on the ceiling or wall that can accommodate luminaires (usually fluorescent lamps or high-voltage fluorescent tubes) for indirect lighting

The Cove reflector is a sophisticated tool used to shape the light of a linear light source. Its parabolic shape and its well-defined cross-section allow it to be set up at right angles to the longitudinal axis of the light source, where its refractive power ensures an ideal lighting effect

The cut-off angle of a luminaire is the angle above which direct reflection from the light source is no longer visible in the reflector. In most cases, this is identical to the cut-off angle of the lamp.

It is like the language robots use to talk to each other when they want lights on or off.

With daylight, you get the best of both words. It's a blend of natural lighting and artificial lighting that keeps your plants healthy and growing.

Daylight factor is a calculation that determines how much daylight illuminates a space and measures how well the lighting integrates with the daylight.

The Daylight simulator is a piece of technical equipment that simulates sunlight and daylight. It provides a brighter, more usable light than an ordinary fluorescent lamp.

A Dichroic reflector is used primarily as coolbeam reflectors, reflecting visible light and transmitting infrared radiation. They are also used for inverse effect outer envelopes on lamps to increase the temperature of the lamp (hot mirror).

Diffused light is soft light, even and free of hot spots, This can be achieved by using one or several diffused lights together to give a perpetual-even glow.

Dimmers are a device used to control the luminous intensity of lights. The most common LED dimmers are phase-cutting dimmers.
All phase-cutting dimmers work by switching the AC mains supply to the LED lamp on and off twice in every mains cycle. This has the effect of reducing the flow of electrical energy to the LED lamp or fixture, so reducing its light output.

This type of light has a single emission angle. By controlling the direction of emitted light, you can create modelling and brilliance effects that are used to achieve various specifications and architectural effects.

A light fixture that hangs in the ceiling and sends light down.

Dynamic White lighting systems provide full control of your LED lighting system and allow for a dynamic range of effects. By imitating the sun and circadian rhythm, Dynamic white can be used for creative impact and to enhance well-being.

Electrical surges are a kind of electricity that can get really big really fast.

Some lights that use too much electricity are being replaced by other lights that use less electricity.

EULUMDAT is a data file format used for specifying how lamp light looks, so people can see what kind of light a lamp will give off.

The amount of light that is visible to a person. Exposure, generally expressed in Lux (lx), is the product of the illuminance and the time it is being illuminated.

The eye is a sensory organ, composed of an optical system (the cornea and lens), a pulsating muscle controlled by the iris and two types of receptors (rods and cones) which transmit incoming light patterns to the brain via optic fiber bundles.

Fascias are detachable covers for the front of a light. They can be used to protect the cone from dirt and damage, but also if you want your light to have a certain look.

The light was moving in a fast back and forth way like a group of kids running around. The dictionary says it is also called flickering.

A Flood is a type of light fixture that provides wide-beam illumination to enable the user to see objects over a wide area.

A fluorescence substance is a chemical that absorbs ultraviolet, visible or infrared radiation, and subsequently emits light of a longer wavelength. Fluorescence is excited by means of radiation and made to produce light. The wavelength of the emitted light is always greater than the excitation wavelength.

A fluorescent lamp is a low-pressure gas-discharge lamp that uses a fluorescent material to produce visible light.

Focal glow provides enough light to see details in darker areas, but lets the background remain in the shadows. The result is a dramatic effect that draws attention to what's important in an image.

A full spectrum light is just a special kind of light that comes from a light bulb. It has different colors than a normal light.

Functional requirements are based on the visual tasks that need to be performed, such as reading or sewing. The aim is to create optimum perceptual conditions for all activities that are to be performed in a specific area.

Gas lights were the first commercially successful, high-intensity electric lights. An early form of lighting using a bare gas flame, ignited by an electric current, to produce light and heat.

Ambient lighting is the type of lighting that fills a room with a soft glow and gives the room a sense of space, without defining any specific visual task.

Our visual system searches to satisfy expectations that are built into our brain. A good example of this is the Gestalt effect: we perceive a group of random dashes as a group, not as individual elements. This works well in many situations, but it makes things like optical illusions so effective as well.

These lights can move to shine light in the direction you want it. They are useful in the places on sloped ceilings.

Glare is the degradation of visual performance or the subjective disturbance felt by perceivers caused by excessive levels of luminance or luminance contrast in a visual environment. It can be divided into physiological glare, which is objective and not dependent on contrast, and discomfort glare, which involves a subjective disturbance factor arising from the incongruity of luminance and information content.

A gobo is a piece of equipment used in stage lighting to produce a shadow on a wall or other surface. The word comes from the Japanese "gobo-pachi" (meaning window cut).

Compact incandescent lamp with additional halides in the gas compound, which prevents deposits of the evaporated filament material forming on the outer envelope. In contrast to general service lamps, halogen lamps have increased luminous efficacy and a longer service life

You can connect your house to the Internet. Then you can control your home with an app on your phone.

Lighting can help people feel healthier and more comfortable. If a room has the right kind of light, it can help people work better and more comfortably.

The acronym IC stands for Insulation Contact. An IC rating, as a result, is essentially a measurement to determine if a downlight is suitable and safe to come in contact with insulation or not.

IES files are three dimensional representations of the intensity of light between points on a spherical grid.

IFTTT is a software platform for connected devices. The company's name comes from programming code. It works with many companies to connect their devices and make them work better.

It's like a rating system to show how strong something is. It's a standard used by different countries.

Illuminance is the measure of light intensity on a surface. While luminous flux relates to the total amount of light emitted, illuminance only refers to the intensity on a particular area.

Interference is a phenomenon which occurs when two or more waves interact with each other. The interference of two waves can be constructive or destructive, depending on the phase difference between them – this determines whether the peaks of one wave coincide with the troughs of another to produce a greater combined amplitude (constructive interference), or whether they cancel each other out completely (destructive interference). Interference results in a range of effects including beat frequency, standing waves and diffraction.

A filter is a device that modifies the properties of a light source, or the light itself. The reason for using a filter is often to make it easier to acquire a desired exposure level.

Ingress Protection (IP) rating is an international standard that indicates the level of protection against the intrusion of solid objects and water.

The isoluminance diagram is a two-dimensional plot of luminance versus retinal illuminant angle recording the brightness of colors on a particular background.

This diagram illustrates the horizontal and vertical components of illuminance on a plane. The values can be measured in lux units to illustrate just how much light is present.

The Kelvin scale has a unit of temperature too. That unit is called a kelvin (no capital letter K in kelvin).

This is a type of light which is the most diffused and has an even light tone. The Lambertian radiator is usually used in light bulbs to provide even and uniform illumination.

A curve that describes the distribution of light through a lens, typically when a single pixel of an image is shown on the screen.

A circuit that uses two out-of-phase devices, such as lamps or motors to improve power factor. The wiring of an inductive fluorescent lamp in parallel with an over-compensated fluorescent lamp can cause the phase difference between the two appliances to be small and thereby improve the overall circuit's power factor.

The leading edge dimming of light control system is to reduce the power to the lamps in series, at the same time, use a variable resistor as a control signal.

LEDs are used to light up buildings. These LEDs are usually housed and protected in profiles, which are made of aluminum. The profiles come in many different shapes, sizes and depths.

The LED driver is a self-contained power supply which has outputs that are matched to the electrical characteristics of the LED(s).

A long thin piece of metal can be used to hold some lights inside of it, and the metal is usually made of aluminum.

LED lights help plants grow with the right colors in the right amounts.

A light beam is a directional projection of light energy radiating from a light source. Sunlight forms a light beam (a sunbeam) when filtered through media such as clouds or foliage.

An often overlooked aspect of luminaire design, light control can make all the difference in a commercial space. Reflectors and lenses used in lighting systems have a big effect on the way we use light - from large architectural projects like concert halls to smaller areas like offices.

Light fastness (light resistance) is a measure of the light-induced colour change, fading, or bleaching of a dyed textile; an indication of how much time it will take for its colour to be affected by exposure to light.

The light loss factor, often referred to as ‘the conversion factor’, quantifies the reduction in performance of a lighting installation due to the ageing of lamps and luminaires.

Light pollution is the disruption of natural light patterns, creating a loss of ecologic biodiversity, hazard to wildlife and human health,erosion of societal quality of life,as well as wasted energy.

It's like doing medical therapy, but instead of doing it with medicine, you do it with lights.

Lighting control allows you to control the lights in your space with greater accuracy and efficiency. For example, you can schedule the lights to dim when you go to bed, or turn on when you get home before you even get into the door.

They have long lights so the light can spread out over a wider area.

LitG is the German Lighting Engineering Society, founded in 1903. It is an organization for international cooperation between lighting engineers and practitioners. LitG awards a prize for the most promising concept in lighting design every year, and publishes relevant material on lighting technology.

A luminaire designed for linear fluorescent lamps, frequently equipped with specular, prismatic or anti-dazzle louvres.

Low-pressure sodium lamps are a type of streetlight. They produce yellow light and do not emit ultraviolet or infrared radiation, making them difficult to illuminate with other types of light sources.

A low-voltage halogen lamp is an extremely compact tungsten halogen lamp operated on low voltage (usually 6, 12 or 24 V). They are frequently used for applications that require long life, high efficacy and a high color rendering index.

Luminaire classification is a classification system for luminaires in the form of lamps, tubes and incandescent lamp that are used to illuminate an area. The first letter indicates whether the luminaire emits light upwards or downwards.

A ratio of the luminous flux emitted by a luminaire to the luminous flux of the lamp. It relates to the actual lamp lumens in the luminaire, and is measured as a percentage.

Luminance is the amount of light emitted from a source, measured in candles per square foot or candelas per square meter. In other words, it’s one way to measure brightness.

A method for evaluating the potential glare of a luminaire using different beam spreads. The luminance of the luminaire with different beam spreads is entered into a diagram, in which it must not exceed the luminance limit for required glare classification.

Luminescence is a term used to describe the phenomenon of light emission. Luminescence can be caused by chemical reactions, physical changes, or electrical properties. These processes can be divided into thermal and nonthermal luminescence.

There is a unique set of colours that can be perceived by the human eye. These colours are called 'luminous' colours and are grouped together in the standard colourimetric system, with each lumi- nous colour being given x and y coordinates as chromacity coordinates. In addition, warm white (ww), neutral white (nw) and daylight white (dw) luminous colours have their own specified temperature value - a 'colour temperature' TF

The luminous efficacy is a measure of how well a lamp converts electricity into light. The lamps, which have the highest luminous efficacy are called high-efficiency bulbs.

Luminous flux is the total amount of light emitted by a light source.

A measure of the total amount of light emitted by a source and per unit solid angle.

It is the curve that shows how much light a light bulb makes in every direction. It is important when designing the light of spaces like offices and theaters.

The reciprocal value of the light loss factor is called the maintenance factor. The value is a decimal instead of a percentage, because to find it, you have to set up and solve an equation.

Light is measured in a new way called Equivalent Melanopic Lux. It's a better way of measuring it based on how the eye actually works, not just what it can see.

The range of light intensity in which we see a combination of cones and rods in our eyes.

Protection against ingress of water is rated for the type of liquid, e.g., water, rain, spray, and also for temperature conditions within a certain range.

The emphasis on three-dimensional forms and surface structures can be explained by the term shadow formation. This term is used in modeling language to describe the use of light from point sources.

Luminaires designed to take tubular fluorescent lamps, with some or all of their sides covered with a transparent louvre.

Monochromatic light is the purest form of light. It has a very narrow spectrum and therefore offers the best possible color rendition and visual acuity.

Mood lighting creates the perfect ambiance for many occasions. It’s a great way to add style and drama to your design, complement your existing fixtures, and set a distinct mood.

Use of light guides to convey light is the preferred method for applications requiring the transport of light around corners, bends and similar obstacles.

Outdoor lights are the perfect fix for lighting up your yard, driveway, and garden. They make great additions to decks, patios and walkways making them safe for nighttime use.

Oyster lights are a type of ceiling light that are easy to attach to the ceiling. They can make the ceilings look higher than they really are.

Sometimes it's hard to see in the dark, especially if you have to walk in a park or a forest. PathLighting makes it easier to see where you're going on the ground by putting pools of light on the ground for you to see.

A hanging light is a light that hangs down from the ceiling on a string, chain, or rod. It's like a necklace for the ceiling.

The field of perception studies how the brain receives and processes information from the senses. It’s our brains that make sense of the information, giving us both shape and color.

Perceptual psychology is the study of how humans detect, perceive and interpret information. It focuses on the psychological processes humans use to make sense of what they see, hear, taste, smell and touch.

Phase dimming is a smart way to save electricity. The electricity comes in as a wave. Phase dimming cuts the power out of one part of the wave.

Light meters are a tool that allows you to measure the light in your environment. They measure lumens, which can be used to figure out if a room is properly lit or if you need to dim the lights for movie night.

The photometric distance of tolerance must be at least ten times the maximum diameter of the lamp or lumi- naire; in the case of optical systems the photometric distance of tolerance is esta- blished by experimentation

Also known as "daylight vision", this is a type of visual perception that occurs via light-receptors in the eyes during or when exposed to light. This type of vision is dependent on the cones of your retina, which are concentrated around the fovea.

Point illuminance expresses the actual illuminance at a specific point within a space. Average illuminance is an average of the illuminance levels in the entire space

The most desirable light source of all times, point light source is bright and easily adjustable, so you can focus the beam onto your subject no matter where or how it moves without fighting the distance.

The power factor is the ratio of real power in watts to apparent power in volt amperes (VA) or kilovolt amperes (kVA).

In many cases, power factor correction is a simple way of increasing the amount of energy you can harvest from your solar panels by converting the worst case scenario (where you are drawing high voltage and low current), into something better suited for harvesting.

Three-phase power is electricity that changes its direction three times. In a home you usually have one of those. In a big, roomy building they usually have three of those.

The Ripple, a power supply that keeps you safe from harmful AC power, delivering clean, safe and constant DC voltage to your devices.

A power surge is when there is an unexpected short burst of electricity. It usually happens when the electrical grid is overtaxed.

Prismatic louvre is a light diffuser and heat insulator that gives a stylish look to your home, office and restaurant. It's made of high-quality acrylic and can also be used as a decorative element.

Classification of luminaires with regard to the rate of protection provided against electric shock

The Re-ignition lamp is a classic function of your light switches. When you turn the light on and off again after a specific time, it is being restarted by its ignitor. This process can be accelerated by modern high-voltage ignitors.

Reflected ceiling plan provides a perspective view of the ceiling from above, giving an overview of how many lights, chandeliers and other fixtures are installed on the ceiling.

The reflection factor of a material is the ratio of the reflected light to the incident light and gives an idea of the ability of a material to redirect light. The higher the reflection factor, the stronger is its ability to reflect light.

A reflector is a device used for lighting. This thing has a special shape to gather light from another source. Some specialize in collecting the light form a particular direction, or a point source of light.

Light shines like a rainbow as it goes through glass. The light bends different amounts in different kinds of glass. That is called refraction.

The bending of light as it passes from one material to another. The refraction of different parts of the spectrum to different degrees gives rise to the formation of colour spectra."

Reflection in rectangular reflector systems (triple mirrors) or transparent spheres, by which the light is reflected parallel to the incident light.

Revit is a building information modeling (BIM) program by Autodesk that is used to create 3D building designs for floor plans, elevations and sections.

Strip lights can change colors and produce white light. Colors are made by mixing the colors red, blue and green. The strips are a rectangular shape with small lights inside them.

The room index helps you easily visualize the geometry of a room to ensure correct illuminance measurements.

SAD lamps are used by people who are sad during the winter. They can also be used to help people who have trouble sleeping and to help people adjust when they travel.

Scallops are produced by grazing wall lighting from downlights, which produces a beautiful texture that resembles a shell found on natural walls in nature.

Scotopic Vision is your ability to see in the dark. It's strictly for darks and my dear ones, not for sunny days.

Some people get depressed when the days get shorter and colder. This happens at the same time every year. If you are one of these people, you have Seasonal Affective Disorder.

The Secondary Reflector technology allows you to direct, or not direct light into a specific area, increasing your control and flexibility over the light output.

A measure of how well a lighting system models the space it is illuminating. Modelling can be described as the ratio of average vertical illuminance (cylindrical) to the horizontal illuminance at a given point in the space.

These lights are smarter than regular lights because they contain sensors that can tell when you have turned them on or off. They also connect to other smart devices.

SmartThings makes devices that let you control your house just like magic.

An angular measure that is equal to the ratio of an area on a sphere to the square of its radius. Similar in concept to a solid angle, only without the actual measure of length.

A spectrometer is a scientific instrument used to separate, measure and identify matter by its spectrum. A spectrometer which works with visible light is called a spectroscope. Spectroscopes are used in astronomy, physics, chemistry and industry.

The spectral distribution of a light source is like the luminous color or the color rendering of a light source that depends on the type of light you have.

Spot is a term used to describe the beam of light from a flashlight.

Spot Lights shine bright, but not so far. Perfect for illuminating your stage set, or creating a smaller niche in your larger space, these lights are smartly designed to help you light up your performance

This is the system for measuring colors with numbers. It will help color scientists to make things look prettier.

A little box used to make lamps light. When you turn on a lamp, the igniter box heats up the lamp so it will light quicker. When the lamp is warm enough, the igniter box stops making heat.

A striplight is a type of bright lamp with colored glass in it. The lamps are wired together and put into a unit. Then you can use dimmers (basically switches for lights) to control the color of the lamps.

When lights blink fast, it makes it hard for people to drive cars and see where they are going. The faster the lights, the harder it is to see. There's a new way to make lights that don't do that anymore.

A surge protector is a thing that protects your stuff from going kaput. Without it, your stuff can get messed up if there is a big zap of electricity, bye-bye!

Surge protection devices help protect your electronic equipment from the damaging effects of an electrical surge.

For all the detail work, task lighting is a necessity. Use Task Lighting to illuminate your workspace and make sure you have the right light to complete any given task.

Task lighting is the obvious solution to your near-sightedness, or lack of concentration. It shines a brilliant, focused beam of light on all your useful stuff, so you can see what you're doing and make it happen.

TM-30 is a way to evaluate the color of light sources.

A track light is a light that moves back and forth, like in a roller coaster.

The ability of a material to allow light to pass through it. This ability is expressed as a percentage, which is defined as the ratio of the amount of light that gets through a material to the amount of light that hits it.

TRIAC dimmers are electronic devices that turn incandescent lights on and off.

UV lights are mostly invisible to the human eye. They make things like black light posters glow. UV light also causes tans and burns. We use it to make food, but too much of it is unhealthy.

Short wave light is invisible radiation. It can fade colors from things like clothing. Wearing sunscreen will keep your clothes from fading. Clothing can be made to protect it from short wave light with chemicals called nylons that act like a sunscreen for clothes.

UGR is a metric that is used to calculate level of glare in certain applications. It will determine how much glare you are exposed to at your desk and make adjustments accordingly.

Utilance is a relation between the light of a luminaire and the room surroundings. It helps to decide, what type of light you want in your home.

The utilisation factor method of calculating illuminance is based on light output ratio (LOR), the utilizable lumens from the lamps and the ceiling surface area.

Ultraviolet light is used to fight germs. It's better than other methods.

VDT-approved luminaires comprise a complete range of halogen and LED type luminaires, each specially designed for the wide range of applications found in offices equipped with visual display terminals.

The Visible Light Spectrum is the segment of the electromagnetic spectrum that can be viewed by the human eye. The visible light spectrum consists of all light we can see and separates into different colors.

The term acuity refers to the ability of the eye to perceive details. It is measured in minutes of arc or degrees. For example, 20/20 vision is equal to 20/10 visual acuity, or having the ability to see something at a distance of twenty feet that an average person with normal vision can see at ten feet away

Quality is a measure of how comfortable we feel when we look at lights. Visual comfort is a special kind of quality that experts invented to help us with lighting.

You have to have enough light or the image is hard to see. The harder it is to see, the lower the grade of difficulty for the task.

When an electrical system has a short burst of energy, it is called a voltage spike.

A wall light is a special kind of light. It doesn't stand up; it hangs from the wall. It's kind of like a picture frame on the wall, with a light in it.

Wall washing is the perfect solution for smooth-walled rooms, making it look like they have been recently painted.

A Home Surge Protection Device, or SPD, is something you can install on your house to protect it from power surges.

The useful working plane is a standardised plane to which illuminances and luminances are related, usually 0.85 m in the case of workplaces and 0.2 m in circulation zones.

Zigbee is a good way to make wireless Internet-things without using a lot of electricity. It uses less electricity than other ways of doing that.

Zoning refers to the division of space into different areas relating to its function.