Color temperature is the color of light emitted by an idealized opaque, non-reflective body at a particular temperature measured in kelvins.
Also, Color temperature is a way to describe the light appearance provided by a light bulb.
Light temperature is a characteristic of visible light that has applications in lighting, photography, videography, publishing, manufacturing, astrophysics, horticulture, and other fields.
In practice, the temperature is meaningful only for light sources that correspond closely to the color of some black body: i.e., light in a range going from red to orange to yellow to white to bluish-white; it does not make sense to speak of the temperature of, e.g., a green or a purple light. Temperature is usually measure in kelvins (K).
Color temperature is a technical characteristic of light sources such as LED lighting. Absolute light temperature is measured in Kelvin using a four digit number.
For example, 2700K, 3000K, 4000K, or 6500K. Color temperatures are also describe as, warm white, cool white, and daylight.
Kelvin Color Temperature Scale
The color temperature scale corresponds to the color of light emitted by an 'ideal black body' at these actual temperatures. We can mostly skip the physics, but here are two examples to try and explain the concept: The sun has an actual temperature of about 5800K (5527˚C). Its emitted radiation peaks in a part of the visual spectrum that we perceive as 'daylight". Molten lava has an actual temperature of about 1300K (1027˚C). The light emitted at this temperature is an intense orange or red 'warm white glow.
Color temperatures over 5000 K are; called "cool colors" (bluish), while lower temperatures (2700–3000) are called "warm colors" (yellowish). "Warm' in this context, is an analogy to a radiated heat flux of traditional incandescent lighting rather than temperature. The spectral peak of warm-colored light is closer to infrared, and most natural warm-colored light sources emit significant infrared radiation. The fact that "warm" lighting, in this sense, has a "cooler" temperature often; leads to confusion.
A good rule of thumb is the higher the temperature, the "cooler" the color. For example, a 5500K hospital-grade bulb is cool than a 2700K bulb you'd likely use in your living room. Most residential lighting applications fall somewhere; on a scale between 2000K and 4500K. It's important to know: what light temperature bulbs you have in fixtures around your home. If you ever replace one with a different temperature than its neighboring light sources, you'll notice they aren't the same "color." Typically, Kelvin temperatures for commercial and residential lighting applications fall somewhere on a scale from 2000K to 6500K.
Warm Light Colors
The light produced in the 2000K to 3000K range on the light color temperature chart is called "warm white." You'll find red and yellow hues that are more flattering to skin tones and clothing, which is why these temperatures; are popular in living spaces.
2700K light bulbs are standard for bedrooms and living rooms to create a cozy atmosphere. Move up to "soft white" 3000K or higher for areas that require more visual tasks like the kitchen, home office, laundry room, and bathroom. In these spaces where warmth and relaxation are not a priority, increase to cool light temperature for more clarity.
TCP has all the warm temperatures covered with energy-efficient LED options for your home. TCP's filament LED bulbs create a very soft light with temperatures below 2700K; or move up to 3000K with our PRO Line family of LEDs. No matter what LED temperature you choose: you'll maximize savings and minimize maintenance costs with TCP Lighting solutions.
Cool Light Colors
On the higher end of the Kelvin scale, blues and greens are called cool colors. Cool light is used for task lighting in a bathroom vanity or kitchen because it generates more contrast. If a neutral white light is important to you, look for light temperatures between 3100K and 4500K. These range from "cool white" to "bright white' with the higher temperatures starting to show a slightly blue tint. These temperatures are brighter, offering a "cleaner" look than warm temperatures.
In living areas with warm, earthy colors, choose 3500K lights. If your paint scheme and home decor skew more toward cool colors, opt for bulbs in the 4000K to 4500K range. TCP's daylight LEDs provide a crisp light with a slightly bluish-white tone.
Color Temperatures of Light Bulbs
A light bulb's temperature lets us know the look and feel of the light produced. The temperature of a light bulb is determined by the corresponding color temperature (CCT). For example, if you heat a metal object, the object appears to glow. The ranges of warm white, cool white, and daylight are subjective.
Depending on the Kelvin temperature; that the metal object; is heated at, the glow will be various colors, such as orange, yellow or blue. If you heat a metal object, it appears to glow. Depending on the Kelvin temperature of the heat, the glow will appear in various colors, such as red, yellow, or blue. The Kelvin temperature scale ranks these colors from warm to cool: or low to high. Using this scale, we can gauge what color of light a bulb produces.
Aside from the type of the light bulb itself, using Kelvin temperature can also help guide you in determining which fixture is right for each room. Whether you need an ambient source of light or one for highly focused task lighting, keep in mind the following Kelvin ranges:
Less than 2000K:
It has a soft glow that resembles a candlelight which makes it ideal for use in dimly lit spaces that requires diffused lighting.
Gives off a soft white glow, often yellow in appearance; best for living rooms, dining rooms, bedrooms, and outdoor spaces.
It emits a bright white light making it ideal for use in kitchens, workplaces, workstations, and vanities that requires task lighting.
Emits a strong amount of blue-white light, similar to that of sunshine, making it ideal for use in exhibition spaces and workplaces that require extremely bright illumination.
6500K and up:
Gives off a bright bluish hue of light, often found in commercial locations; best for bright task lighting.
How to measure color temperature?
Warm White 2400K-3000K
Many customers enjoy warm tones that match up to incandescent light bulbs which fall into the 2700K - 2800K range. There are some exceptions, such as neodymium bulbs made by Chromalox have a coating that filters out yellow and red wavelengths. The light bulbs and fixtures that mimic warm white color temperature are commonly used in restaurant lighting, residential lighting, hotel walkways, and rooms and spaces where a warm ambiance is needed to set the mood.
Neutral White 3500K
This color temperature is popular in offices and commercial buildings: it is the light temperature that; falls in the middle of warm white 3000K and cool white 4000K. Also, many of the F32T8 lamps sold are in the high CRI range of 80+ with a temperature of 3500K.
Cool White 4000K-4300K
Cool white is also popular in offices and commercial buildings; as you move up the color scale, you get some yellows starting to show up and some more bluish-white light.
Full Spectrum 5000K-5765K
The word "full spectrum" refers to very balanced light. Typically, when you get to 5000K-5765K temperatures: referred to as; falling into the full spectrum range. When you visually look at the light, you see a very white, crisp clean-looking light that is appealing for modern spaces, paint booths, gas stations, hospitals, and office environments.
You would think daylight would be the same color as the light outside; however, it is far from that. Daylight gets into the blue spectrum, and you start seeing less of the yellows and whites. You will still have what appears to be a bright light, but; when compared to the full spectrum, you can visually; see the blue light starting to take over the light color.
The color temperature of a light source in a specific room or space may have a dramatic effect; on the people using that particular light, whether it is to perform a task, relax or learn. For this reason, it is necessary to choose the right temperature for a given application.
The golden rule: ALWAYS check color temperature before you spend your money. Ensure all light sources in a room match, including any light fixtures like cooker hoods or bathroom mirrors.
Color temperature discrepancies are more apparent when two lights of different colors are next; to each other. Mismatched lighting can seem incongruous. So, whatever you choose, keep the light temperature consistent within a space.
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