Common Lighting Terms
A | B | C |D |E |F |G |H |I |J |K |L |M |N |O |P |Q |R |S |T |U | V | W | X | Y | Z
A

ADHD (Attention-deficit hyperactivity disorder): Is a behavioral condition in which children have difficulties paying attention and focusing on tasks. This common disorder begins in early childhood and can continue into adulthood. If not recognized and treated, it can cause problems at home, school, and work and with relationships.


Amperage: The strength of an electrical current measured in amperes


Amp: The basic unit of electric current adopted under the System International d'Unites; "a typical household circuit carries 15 to 50 amps"


Anxiety: A state of apprehension, uncertainty, and fear resulting from the anticipation of a realistic or fantasized threatening event or situation, often impairing physical and psychological functioning.


Artificial Dawn Simulator: An electronic device used to slowly increase interior lighting levels simulating a natural sunrise situation.

B

Balanced Spectrum: A marketing term used to infer full spectrum lighting is being used in a particular lamp when the lamp itself does not actually meet the requirements to be called a full spectrum light source.


Ballast - Electronic: An electrical device for starting and regulating fluorescent and discharge lamps. These types of ballasts do not use older magnetic coils but use electronic systems to convert current to the proper voltage for lamp ignition. Typically much more energy efficient than older style magnetic ballasts and produce no lamp flicker.


Ballast Factor: The ratio of lamp lumen output on a particular ballast as compared to that lamp's (lamps') rated lumen output on a reference ballast under ANSI test conditions (free, unmoving air at 25° C)


Ballast - Magnetic: Older style ballast using a magnetic core and coil to convert electrical current to a proper voltage to run a lamp. Typically create a lot of heat, are not very energy efficient, and cause lamp flicker due to a 60 Hz operating cycle.


Bi-pin Medium: Lamp holder typically used for T8, T10, and T12 fluorescent lamps.


Bi-pin Mini: Lamp holder typically used for T5 fluorescent lamps.


Bi-Polar Disorder: Bipolar disorder is a condition that causes extreme shifts in mood, energy, and functioning.


Bright Light Therapy: Light therapy for seasonal affective disorder using a fixture that produces a minimum of 10,000 lux at a distance of 12 inches from the source.


Bulb Lifetime: Also called rated lifetime. The expected lifetime of a bulb determined through laboratory testing. Individual results may vary according to on/off cycles and ambient conditions.


C

Cathode: The negative electrode of a lamp where electron emmisions are created.


Chromacity: Chromacity tells you what the lamp itself or a neutral surface illuminated by a lamp will look like. Chromacity sets the "tone" or atmosphere of a room: warm, cool or something in between. Chromacity (sometimes called color temperature) is usually measured in Kelvins. It can also be defined by using x and y coordinated against a standard chromacity scale determined by the Commission Internationale de l'Éclairage (CIE)


Chronic Fatigue Syndrome: Is a condition of excessive fatigue, cognitive impairment and other varied symptoms. Classified by the World Health Organization (WHO) as a disease of the nervous system, it is of unknown etiology and may last months or years, causing severe disability.


Circadian Clock: Is a name given to the "internal body clock" that regulates the (roughly) 24 hour sleep/wake cycle.


Circadian Rhythms: Is a name given to the "internal body clock" that regulates the (roughly) 24 hour cycle of biological processes in animals and plants. Responsible for sleep/wake cycles in humans.


Clarity: Refers to one's ability to visualize an object clearly. The higher the clarity the more concisely one can see an object.


Color Rendering Index (CRI): Is a measure of the quality of light. A measurement of the amount of color shift that objects undergo when lighted by a light source as compared with the color of those same objects when seen under a reference light source of comparable color temperature. CRI values generally range from 0(worst) to 100(best). CRI is very similar to your contrast knob on your TV set. High CRI equates to sharper, crisper, more natural colored pictures while at the same time reducing glare.


Color Temperature: A measure of the color of a light source relative to a black body at a particular temperature expressed in degrees Kelvin (K). Incandescent lights have a low color temperature (approximately 2800K) and have a red-yellowish tone; daylight has a high color temperature (approximately 6000K) and appears bluish (the most popular fluorescent light, Cool White, ia rated at 4100K). Today, the phosphors used in fluorescent lamps can be blended to provide any desired color temperature in the range from 2800K to 6000K. Lamps with color temperatures below 5000K tend to be more yellow/red, lamps rated between 5000 and 6000K are viewed as white, while lamps above 6000K tend to have a blue cast.


Compact Fluorescent: Is a type of fluorescent lamp which screws into a regular light bulb socket, or plugs into a small lighting fixture. In contrast to incandescent light bulbs, they have a longer life and use less electricity.


Cones: The photoreceptors in the human eye responsible for seeing colors.


Cool White Fluorescent Lighting: Standard fluorescent lamps typically rated at 4100K color temperature and a color rendering index of around 62-65. A very common form of lamp that does not act as a good source of light. Commonly associated with headaches and a jittery feeling while in use.


Cortisol: Is a corticosteroid hormone that is involved in the response to stress; it increases blood pressure and blood sugar levels and suppresses the immune system. Cortisol has been shown to be released in increased amounts among people when exposed to poor lighting sources such as standard cool white fluorescents.


CRI (Color Rendering Index): Is a measure of the quality of light. A measurement of the amount of color shift that objects undergo when lighted by a light source as compared with the color of those same objects when seen under a reference light source of comparable color temperature. CRI values generally range from 0(worst) to 100(best). CRI is very similar to your contrast knob on your TV set. High CRI equates to sharper, crisper, more natural colored pictures while at the same time reducing glare.

D

Dawn Simulator: An electronic device used to slowly increase interior lighting levels simulating a natural sunrise situation.


Daylight Lamps: Typically used to describe lamps with a 6500K color temperature rating. Because of the bluish hue cast from these lamps colors tend to look washed out and dull compared to a true full spectrum light source. Also referred to by some companies as "balanced spectrum", "wide spectrum", "natural spectrum" and numerous other marketing terms.


Degrees Kelvin: A measure of the color of a light source relative to a black body at a particular temperature expressed in degrees Kelvin (K). Incandescent lights have a low color temperature (approximately 2800K) and have a red-yellowish tone; daylight has a high color temperature (approximately 6000K) and appears bluish (the most popular fluorescent light, Cool White, ia rated at 4100K). Today, the phosphors used in fluorescent lamps can be blended to provide any desired color temperature in the range from 2800K to 6000K. Lamps with color temperatures below 5000K tend to be more yellow/red, lamps rated between 5000 and 6000K are viewed as white, while lamps above 6000K tend to have a blue cast.


Depression: A mental state characterized by a pessimistic sense of inadequacy and a despondent lack of activity


Desk Lamp: A task lamp used to directly illuminate a flat surface such as a desk or table. Typically these lamps sit directly upon the surface they are illuminating.

E

Electronic Ballast: An electrical device for starting and regulating fluorescent and discharge lamps. These types of ballasts do not use older magnetic coils but use electronic systems to convert current to the proper voltage for lamp ignition. Typically much more energy efficient than older style magnetic ballasts and produce no lamp flicker.


Endocrine System: Is a control system of ductless endocrine glands that secrete chemical messengers called hormones that circulate within the body via the bloodstream to affect distant organs.


Eye Fatigue: Tiredness of the eyes caused by too much movement of the eye itself or excessive adaptive response of the pupil caused by scotopically poor lighting sources. Scotopically enhanced light sources can eliminate this affect.


Eye Strain: Eyestrain occurs when you over-use your eye muscles in order to focus on a task or object. Scotopically enhanced light sources can eliminate this problem through increased visual acuity from a smaller pupil diameter.

F

Fixture Efficiency: The ratio of light emitted from a fixture versus the light emitted by the lamp(s) contained in the fixture expressed as a percentage.


Floor Lamp: A tall lamp with a base that stands on the floor used for direct lighting of a task or reading surface.


Fluorescent Lamp: Is a type of lamp that uses electricity to excite mercury vapor in argon or neon gas, producing short-wave ultraviolet light. This light then causes a phosphor to fluoresce, producing visible light to the user.


Fluorescent T5: A fluorescent lamp that is five-eighths of an inch (.625") in diameter. These lamps are among the newest form of fluorescent lamps with energy efficient high light output characteristics. Tend to create more heat and have a shorter lifespan than other fluorescent lamps. Require an electronic ballast to operate.


Fluorescent T8: A fluorescent lamp that is eight-eighths of an inch (1.0") in diameter. These lamps are more energy efficient than the older T12 lamps but do not have the lumen output that newer T5 lamps produce. Require an electronic ballast to operate.


Fluorescent T10: A fluorescent lamp that is ten-eighths of an inch (1.25") in diameter. These lamps are not very common.


Fluorescent T12: A fluorescent lamp that is twelve-eighths of an inch (1.5") in diameter. These lamps were very common until the mid 1990s when more energy efficient T8 and now T5 were introduced.


Foot-Candle: The unit is defined as the amount of illumination the inside surface an imaginary 1-foot radius sphere would be receiving if there were a uniform point source of one candela in the exact center of the sphere. Basically, the amount of light that a single candle would provide to a 1ft. radius sphere.


Full Spectrum: A light bulb or lamp that produces a light spectrum that covers the entire range of visible light (400-700nm) without gaps in its spectral output.

G

Gooseneck Desk or Floor Lamp: A lamp that has a flexible area near the head of the lamp that allows you to adjust the angle at which light strikes your eye or work surface.

H

Halogen Floor Lamp: Floor lamp or torchiere that uses a high temperature halogen bulb. A serious fire and burn threat to all that use them.


Halogen Light Bulbs: The incandescent light bulb uses a glowing wire filament heated to white-hot by electrical resistance, to generate light. The bulb is the glass enclosure which keeps the filament in a vacuum or low-pressure noble gas or a halogen gas in the case of quartz-halogen lamps in order to prevent oxidation of the filament at high temperatures. A serious fire and personal burn threat when used in the home or office.


Halogen Torchieres: Floor lamp or torchiere that uses a high temperature halogen bulb. A serious fire and burn threat to all that use them.


Healthy Lighting: Full Spectrum Lighting designed to bring healthful benefits to its users. Examples include light therapy to treat depression, increase mood and awareness, reduce eye fatugue, etc.


High Bay Fixture: Lighting fixtures designed to illuminate larger spaces typically from heights above 12ft. from the surface.


High Definition Lighting: Full Spectrum Lighting with scotopic enhancements that allow the user to see with increased visual acuity over standard full spectrum or daylight bulbs.


Hour Rating: Also called rated lifetime. The expected lifetime of a bulb determined through laboratory testing. Individual results may vary according to on/off cycles and ambient conditions.

I

Illumination: Supplying light to an area. Also refers to the density of light over a given area ie. high illumination refers to a high density of light.


Intensity: Is a measure of the time-averaged energy flux or amount of light striking a given area. For bulbs alone this is measured in terms of lumens while for lighting fixtures it is measured in lux (lumens/sq. meter).


Interior Lighting: Light and light fixtures designed to be used indoors.

J
K

Kelvin Temperature: A measure of the color of a light source relative to a black body at a particular temperature expressed in degrees Kelvin (K). Incandescent lights have a low color temperature (approximately 2800K) and have a red-yellowish tone; daylight has a high color temperature (approximately 6000K) and appears bluish (the most popular fluorescent light, Cool White, ia rated at 4100K). Today, the phosphors used in fluorescent lamps can be blended to provide any desired color temperature in the range from 2800K to 6000K. Lamps with color temperatures below 5000K tend to be more yellow/red, lamps rated between 5000 and 6000K are viewed as white, while lamps above 6000K tend to have a blue cast.

L

Lifetime Rating - Bulbs: Also called rated lifetime. The expected lifetime of a bulb determined through laboratory testing. Individual results may vary according to on/off cycles and ambient conditions.


Light Box: Consists of exposure to specific ranges of light wavelengths or very bright, full-spectrum light, for a prescribed amount of time. It has proven effective in treating seasonal affective disorder (SAD), and for some people it has ameliorated delayed sleep phase syndrome. Light boxes are typically just that, a box shaped fixture creating bright illumination outward toward the user.


Light Intensity: Is a measure of the time-averaged energy flux or amount of light striking a given area. For bulbs alone this is measured in terms of lumens while for lighting fixtures it is measured in lux (lumens/sq. meter).


Light Spectrum: Typically the visible light spectrum from 400nm to 700 nm wavelengths.


Light Therapy: Consists of exposure to specific ranges of light wavelengths or very bright, full-spectrum light, for a prescribed amount of time. It has proven effective in treating seasonal affective disorder (SAD), and for some people it has ameliorated delayed sleep phase syndrome.


Light Therapy Box: Consists of exposure to specific ranges of light wavelengths or very bright, full-spectrum light, for a prescribed amount of time. It has proven effective in treating seasonal affective disorder (SAD), and for some people it has ameliorated delayed sleep phase syndrome.


Light Therapy Products: Any product that is capable of producing the required light output in order to treat symptoms of seasonal affective disorder or winter depression.


Low Bay Fixture: Lighting fixtures designed to illuminate larger spaces typically from heights below 12ft. from the surface.


Lumen Maintenance: How well a light bulb is able to retain its intensity when compared to new. Typically light sources such as high intensity discharge lamps have a very poor lumen maintenance loosing up to 40% of their original intensity over a 6 month period compared to a quality fluorescent bulb that looses only 10% of its intensity over the same period.


Lumens: The unit of luminous flux in the International System, equal to the amount of light given out through a solid angle by a source of one candela intensity radiating equally in all directions. Used to measure light bulbs as stand alone light sources while lighting fixtures are measured by lux ouput which is lumens per square meter.


Lux: Typically used to measure the light intensity produced by a lighting fixture. The higher the lux reading the more light the lighting fixture is producing over a given area. Known as lumens per square meter.

M

Magnetic Ballast: Older style ballast using a magnetic core and coil to convert electrical current to a proper voltage to run a lamp. Typically create a lot of heat, are not very energy efficient, and cause lamp flicker due to a 60 Hz operating cycle.


Magnifying Lamp: A lighting fixture fitted with a magnifying lense to increase lighting intensity over a very small area.


Malillumination: Refers to a poor lighting source, such as cool white fluorescents, that can cause eye fatigue, increased stress hormone levels, and overall poor health for its users.

Medium Bi-Pin: Lamp holder typically used for T8, T10, and T12 fluorescent lamps.


Melatonin: A hormone derived from serotonin and produced by the pineal gland that stimulates color change in the epidermis of amphibians and reptiles and plays a role in sleep, aging, and reproduction in mammals.


Mini Bi-Pin: Lamp holder typically used for T5 fluorescent lamps.

N

Nanometers: One billionth (10-9) of a meter abbreviated as "nm". Used to measure the wavelengths of light. The lower the wavelength eg. 400nm the bluer and stronger the light source. Longer wavelengths such as 700nm are red and contain less energy.


Natural Light: Light that accurately replicates the light produced by the sun and strikes the earth.


Natural Light Bulb: A light bulb that accurately replicates the light produced by the sun.


Natural Lighting: Lighting that accurately replicates the light produced by the sun.


Natural Sunlight: The light that is produced by the sun and strikes the earth's surface.


Neodymium: A rare earth element that is used to coat incandescent bulbs to filter out much of the yellow and red light output.

O
P

Parabolic Reflector: Is a reflective device formed in the shape of a paraboloid of revolution. Parabolic reflectors can either collect or distribute energy such as light, sound, or radio waves.


PCF: Acronym for Power Compact Fluorescent Is a type of fluorescent lamp which screws into a regular light bulb socket, or plugs into a small lighting fixture. In contrast to incandescent light bulbs, they have a longer life and use less electricity.


Phosphor: Coating on the inside of a fluorescent bulb that when struck by electron emissions created by the lamp cathode produce colors of visible light. Typical fluorescent lamps use 2-3 phosphors while BlueMax™ use a five phosphor blend to produce a light rich in all colors of the spectrum.


Photopic: The light output response of a person only during high light levels and does not take into account the role that rods and pupil size have on visual acuity. A light source that is rich in both photopic and scotopic illuminance is considered an ideal light source.


Photopic Response: The response of the eye to only bright light without any scotopic (blue) enhancement. The photopic response peaks in the green light portion of the spectrum around 550nm. The scotopic response peaks more toward the blue end of the visible spectrum at 480nm.


Photoreceptor: A nerve ending, cell, or group of cells specialized to sense or receive light.


Pineal Gland: A small, cone-shaped organ in the brain of most vertebrates that secretes the hormone melatonin. Also called epiphysis, pineal body, pineal organ.


Posillumination: A term used to refer to a light source that provides positive health benefits while at the same time providing adequate illumination.


Power Compact Fluorescent: Is a type of fluorescent lamp which screws into a regular light bulb socket, or plugs into a small lighting fixture. In contrast to incandescent light bulbs, they have a longer life and use less electricity.


Pupil: In the eye, the pupil is the hole in the middle of the iris. It appears black because most of the light entering it is absorbed by the tissues inside the eye. In humans and many animals (but few fish), the size of the pupil is controlled by involuntary contraction and dilation of the iris, in order to regulate the intensity of light entering the eye.


Pupil Diameter: The measurement of the pupil from one edge to the other. Smaller pupil diamters result in less lighting glare and better visual acuity for comples reading or work tasks.

Q
R

Rated Hours: Also called rated lifetime. The expected lifetime of a bulb determined through laboratory testing. Individual results may vary according to on/off cycles and ambient conditions.


Reading Lamps: Lamps used for the purpose of seeing text on a page. Scotopic enhanced lighting provides increased visual acuity for reading lamps by decreasing the pupil size to reduce glare and increase focus as well as makes the micro borders between the black text and white page have more contrast and sharper edges.


Recessed Double Contact: A lamp connection type consisting of a recessed area at the end of the bulb with two internal contact area for a two-pin lamp holder. The opposite of most lamps that have the pins attached to the lamp rather than the lamp holder.


Retina: A delicate, multilayered, light-sensitive membrane lining the inner eyeball and connected by the optic nerve to the brain.


Rheostat: A continuously variable electrical resistor used to regulate current. Used as a dimmer switch for lighting aparatus.


Rods: Name of the photoreceptors found in the retina of the human eye responsible for pupil diameter and seeing in shades of gray.

S

SAD (Seasonal Affective Disorder): Is an affective, or mood disorder. Most SAD sufferers experience normal mental health throughout most of the year, but experience depressive symptoms in the winter.


Sad Light: A lighting device designed to create significant lighting intensity to treat seasonal affective disorder and its symptoms. Typically a minimum light output of 10,000 lux at a distance of 12" from the light source.


Sad Light Boxes: Consists of exposure to specific ranges of light wavelengths or very bright, full-spectrum light, for a prescribed amount of time. It has proven effective in treating seasonal affective disorder (SAD), and for some people it has ameliorated delayed sleep phase syndrome. Light boxes are typically just that, a box shaped fixture creating bright illumination outward toward the user.


Scotopic: The ability to see in darkness or dim light; dark-adapted vision.


Scotopic Lumens: Light lumens that are wihtin the scotopic response curve of the retina. The scotopic response peaks more toward the blue end of the visible spectrum at 480nm. A light source that is rich in both photopic and scotopic illuminance is considered an ideal light source.


Scotopic Response: The response of the eye to light with scotopic (blue) enhancement. The scotopic response peaks more toward the blue end of the visible spectrum at 480nm. The photopic response peaks in the green light portion of the spectrum around 550nm. An ideal light souce will be rich in both photopic and scotopic illumination.


Scotopic Sensitivity: Scotopic Sensitivity Syndrome or sometimes referred to as Irlen Syndrome after Helen Irlen, who in the early 1980's discovered that some people with poor reading showed a marked and immediate improvement by simply overlaying the pages with coloured plastic (e.g. acetate sheets). It is believed that this condition affects, to varying degrees, approximately 12% of the population and that the condition is somehow caused by the brain and/or eye incorrectly processing/interpreting what the eye is seeing (i.e. it is neurological).


Scotopically Enhanced: A light source that takes into account the role that the rods play in daytime vision by increasing the blue wavelengths of light. This enhancement causes reduced pupil sizes eliminating glare and increasing visual acuity.


Seasonal Affective Disorder: Is an affective, or mood disorder. Most SAD sufferers experience normal mental health throughout most of the year, but experience depressive symptoms in the winter.


Seasonal Affective Disorder Light Therapy: Consists of exposure to specific ranges of light wavelengths or very bright, full-spectrum light, for a prescribed amount of time. It has proven effective in treating seasonal affective disorder (SAD), and for some people it has ameliorated delayed sleep phase syndrome.


Serotonin: An organic compound formed from tryptophan and found in animal and human tissue, especially the brain, blood serum, and gastric mucous membranes, and active in vasoconstriction, stimulation of the smooth muscles, transmission of impulses between nerve cells, and regulation of cyclic body processes.


Single Pin Connection: A type of lamp connection where the bulb has a single round pin at each end compared to the two pin or recessed contact connectors used on some bulbs.


Sleep Disorder: Is a disorder in the sleep patterns of a person or animal. Some sleep disorders can interfere with mental and emotional function, due to their interference with REM sleep.


Spectral Chart: A chart showing the relative spectral output of a lamp or light source.


Spectrum: The distribution of energy emitted by a radiant source, as by an incandescent body, arranged in order of wavelengths.


Stress Hormones: Hormones produced by the body in response to actual or perceived stress. Poor lighting conditions have been shown to increase stress hormones in human test subjects.


Subsyndromal SAD: Characterized by or exhibiting symptoms that are not severe enough for diagnosis as a clinically recognized seasonal affective disorder.


Sunlamp: A lamp that radiates ultraviolet rays used in therapeutic and cosmetic treatments.


Sunlight: The light of the sun; sunshine.


Sunlight Starvation: A lack of adequate natural light and light spectrum which can cause health problems such as seasonal affective disorder.

T

T5 Bulb: A fluorescent lamp that is five-eighths of an inch (.625") in diameter. These lamps are among the newest form of fluorescent lamps with energy efficient high light output characteristics. Tend to create more heat and have a shorter lifespan than other fluorescent lamps. Require an electronic ballast to operate.


T8 Bulb: A fluorescent lamp that is eight-eighths of an inch (1.0") in diameter. These lamps are more energy efficient than the older T12 lamps but do not have the lumen output that newer T5 lamps produce. Require an electronic ballast to operate.


T10 Bulb: A fluorescent lamp that is ten-eighths of an inch (1.25") in diameter. These lamps are not very common.


T12 Bulb: A fluorescent lamp that is twelve-eighths of an inch (1.5") in diameter. These lamps were very common until the mid 1990s when more energy efficient T8 and now T5 were introduced.


Task Lamp: A lamp used to specifically light a particular area used for work or reading. Typically found in the form of a desk, floor, or clamp-on lamp.


TCLP Compliant: Term used for lamps that pass the US EPA's toxic characteristic leaching process. The EPA uses this procedure to determine whether certain toxic substances are likely to move from a landfill into groundwater. Lamps not classified as hazardous waste are more accurately termed "TCLP compliant.


Torchiere: A floor lamp that directs light upward for an indirect lighting effect.

U

Ultraviolet Light: The portion of the electromagnetic spectrum with wavelengths from about 100 to 380 nm. UV light is typically broken into three parts, UV-A, UV-B, and UV-C.


UV-A: (380–315 nm), also called Long Wave or "blacklight" because it is invisible to the human eye. Can cause skin irritation and fading of fabrics.


UV-B: (315–280 nm), also called Medium Wave radiation. Can cause severe damage to the skin and human eye through exposure..


UV-C: (< 280 nm), also called Short Wave or "germicidal" for its ability to destroy even bacterial lifeforms. Extremely hazardous to all lifeforms due to its immediate damage to cellular DNA.

V

Visible Spectrum: Is the portion of the electromagnetic spectrum that is visible to the human eye.


Visual Acuity: Is the eye's ability to detect fine details and is the quantitative measure of the eye's ability to see an in-focus image at a certain distance.


Visual Clarity: Refers to one's ability to visualize an object clearly. The higher the clarity the more concisely one can see an object.


Voltage: A quantity measured as a signed difference between two points in an electrical circuit which, when divided by the resistance in Ohms between those points, gives the current flowing between those points in Amperes, according to Ohm's Law. Voltage is expressed as a signed number of Volts (V). The voltage gradient in Volts per meter is proportional to the force on a charge.


Volts: The International System unit of electric potential and electromotive force, equal to the difference of electric potential between two points on a conducting wire carrying a constant current of one ampere when the power dissipated between the points is one watt.

W

Wattage: An amount of power, especially electric power, expressed in watts or kilowatts.


Watts: The unit for measuring electrical power. It defines the rate of energy consumption by an electrical device when it is in operation. The energy cost of operating an electrical device is calculated as its wattage times the hours of use. In single phase circuits, it is related to volts and amps by the formula: Volts x Amps x PowerFactor = Watts.


Wide Spectrum: A marketing term used to infer full spectrum lighting is being used in a particular lamp when the lamp itself does not actually meet the requirements to be called a full spectrum light source.


Winter Blues: Typically used to describe the symtoms associated with seasonal affective disorder or subsyndromal SAD. Feelings of lethargy, increased appetite, increased sleepiness, and feelings of rejection.


Winter Depression: Typically used to describe the symtoms associated with seasonal affective disorder or subsyndromal SAD. Feelings of lethargy, increased appetite, increased sleepiness, and feelings of rejection.

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