In this article I will touch upon a few questions that interest me about the lighting and illumination of a car, as well as a mini review of different bulbs. So the questions:
"I took xenon 5000K" - what is 5000K and what kind of xenon can be? and what kind of lamp is this xenon? and what other lamps are there?
5000K - Colour temperature in kelvin. Using this figure, you can calculate the light that the bulb will shine with. and vice versa, you can estimate the temperature by color (well, of course, colored bulbs are not taken into account)).
In general, any light source has a color temperature. Hot iron, for example, has a color temperature of about 800K, an ordinary incandescent light bulb of 100 W - 2800K, the sun at noon - 5000K, cloudiness - 7500K, clear blue skies in winter - 15000K. It is noteworthy that in all digital cameras you can set the "sun", "cloudy" mode, etc. - this is the setting of this very color temperature for believable color reproduction of photographs.
Xenon is inert gas and the lamp itself is called a "xenon arc lamp" or "xenon discharge lamp". The first such lamp was introduced by Osram in 1951. The lamp gives a bright white light, close to the daytime spectrum, but has a rather low efficiency.
V car headlights Mercury-xenon lamps are widespread, in which xenon is used only for the start-up time, and the main luminous flux is formed by mercury (in fact, these lamps are more metal-halide than xenon).
mercury xenon lamp
Generally gas discharge lamps have a longer service life compared to incandescent lamps and high efficiency and profitability. Radiation color: from 2200 to 20000K! These include fluorescent lamps, metal halide, mercury, sodium, neon (by the way, neon is a red glow, and other gases are used to achieve other colors, such as mercury or phosphorus), etc.
metal halogen lamps
sodium gas discharge lamp
But halogen lamps (not to be confused with metal halide) are not gas-discharge ones. It can be said to be a tuned incandescent lamp, where a conventional incandescent lamp is filled with bromine or iodine vapor. has a temperature of about 3000K, which gives the same warm color as an incandescent lamp, but less pronounced.
halogen lamp
So how do you tell a color from a color temperature? The range itself goes from red (infrared) to blue (ultraviolet):
up to 1000 - Red
1000-1500 - Orange
1500-2000 - Yellow
2000-4000 - Pale yellow
4000 - 5500 - Yellowish white
5500-7000 - Pure white
7000-9000 - Bluish white
9000-15000 - White-blue
15000 and above - Blue
More clearly - 3400 K - the sun is near the horizon;
3800 K - lamps used to illuminate meat products in a store (they have an increased content of red in the spectrum);
4200 K - fluorescent lamp (warm white light);
4300-4500 K - morning sun and sun at lunchtime;
4500-5000 K - xenon arc lamp, electric arc;
5000 K - sun at noon;
5500 K - clouds at noon;
5500-5600 K - photo flash;
5600-7000 K - fluorescent lamp;
6200 K - close to daylight;
6500 K - standard source of daily white light close to midday sunlight;
6500-7500 K - cloudiness;
7500 K - daylight, with a large proportion of scattered from the clear blue sky;
7500-8500 K - fog;
9500 K - blue cloudless sky on the north side before sunrise;
10,000 K - "infinite temperature" light source used in reef aquariums (actinic blue);
15000 K - clear blue sky in winter;
20,000 K - blue sky in polar latitudes;
What about LEDs? LEDs, I will say, are more abruptly than all other lamps (arc, incandescent, gas-discharge). Makes in all characteristics - vandal-proof, safe, economical, low ultraviolet and infrared radiation (which in certain conditions can be harmful to humans), low heat generation, small size and, most beloved, the ability to get any color (in incandescent lamps, light filters are used. gas discharge various gases). However, there are also disadvantages - high cost, low limiting temperature (in some cases, requires good cooling). The spectrum of modern LEDs is different - from warm white = 2700 K to cold white = 6500 K. I will write about LEDs in a separate article - this is a separate big topic.
Color temperature is the most important characteristic of LED electrical products. It is he who depends on how comfortable you will feel in the interior, illuminated by LED lamps, ribbons or lamps.
Color temperature is measured in degrees Kelvin (K). According to European standards, all light sources are divided into three groups in terms of color:
- warm white (TC = below 3500 K)
- neutral white or daylight (TC = 3500-5300 K)
- cold white (TC = above 5300 K)
The color temperature of the usual incandescent lamp is about 2 800 K, therefore warm white light glow LED lamps most familiar to the eye (from 2700 to 3500K).
For most types of work and premises, "neutral" light sources are recommended (Ttsv = 4000 - 4500 K). If we talk about the effect of color temperature on a person, then warm light relaxes and creates an atmosphere of coziness, while colder tones help the body to concentrate and tune in to a working mood.
Workplace lighting
In the workplace, the color temperature should be as close to the color as possible natural light... If, with white light (daylight) and long-term work of a person, we take its output as 100%, then with yellow light it will be only 93%, with green 92%, with blue 78%, with red and orange 76%. Those. in the workplace, daylight will be more useful (about 4000 - 4500 K).
For reading, a colder white light is useful (but only up to 6500 K):
Color temperature in different rooms of the house
While our eyes have become accustomed to the soft white color temperature of an incandescent lamp over the years, this does not mean that they are necessarily the most the best option to illuminate the whole house. For example, due to their warm color temperature, these soft white lights often pull warm colors from the room (objects of red, orange), change the contrasts in the entire space. V from a few tips on how to most effectively illuminate different rooms in your house:
Soft White / Warm White (2700-3500K):
Best suited for bedrooms and living rooms, creating a traditionally warm and cozy feel in these rooms. Also soft light is good for dining table lighting.
Bright white / cold white (5300 - 6500 K):
Best in kitchens, bathrooms or garages, cheering you up by creating a more energetic mood.
Daylight (4000 - 5000 K):
Best for bathrooms, kitchens and basements; ideal for reading, for working with complex projects, or for applying makeup - provides the greatest contrast between colors.
There is another point: the color temperature of your light source affects perception. different colors in your interior.
Any object in the world around us has a temperature above absolute zero, which means it emits thermal radiation. Even ice, which has a negative temperature, is a source of thermal radiation. It’s hard to believe, but it’s true. In nature, the temperature of -89 ° C is not the lowest; even lower temperatures can be reached, however, so far, in laboratory conditions. The most low temperature, which at the moment is theoretically possible within our universe, is the temperature of absolute zero and it is equal to -273.15 ° C. At this temperature, the movement of molecules of matter stops and the body completely ceases to emit any radiation (thermal, ultraviolet, and even more so visible). Complete darkness, no life, no warmth. Some of you probably know that color temperature is measured in Kelvin. Who bought his home energy saving light bulbs, he saw the inscription on the package: 2700K or 3500K or 4500K. This is precisely the color temperature of the light emission from the bulb. But why is it measured in Kelvin, and what does Kelvin mean? This unit of measurement was proposed in 1848. William Thomson (aka Lord Kelvin) and officially approved in the International System of Units. In physics and sciences, having direct relation to physics, thermodynamic temperature is measured just Kelvin. Start of report temperature scale starts from point 0 Kelvin what do they mean -273.15 degrees Celsius... That is 0K- That's what it is absolute zero temperature... You can easily convert the temperature from Celsius to Kelvin. To do this, you just need to add the number 273. For example, 0 ° C is 273K, then 1 ° C is 274K, by analogy, a human body temperature of 36.6 ° C is 36.6 + 273.15 = 309.75K. It’s just that simple.Blacker than black
How does it all start? Everything starts from scratch, including light emission. Black Colour is the absence Sveta at all. From the point of view of color, black is 0 radiation intensity, 0 saturation, 0 hue (there is simply none), this is the complete absence of all colors at all. Why do we see an object as black, but because it almost completely absorbs all the light falling on it. There is such a thing as absolutely black body ... An idealized object is called an absolutely black body, which absorbs all radiation incident on it and does not reflect anything. Of course, in reality this is unattainable and absolutely black bodies do not exist in nature. Even objects that appear black to us are not actually completely black. But it is possible to make a model of an almost completely black body. The model is a cube with a hollow structure inside; a small hole has been made in the cube through which light rays penetrate into the cube. The design is somewhat similar to a birdhouse. Take a look at Figure 1.Figure 1 - Black body model.
Light entering through the hole will be completely absorbed after multiple reflections, and the hole will appear completely black from the outside. Even if we paint the cube black, the hole will be blacker than the black cube. This hole will be black body... In the truest sense of the word, the hole is not a body, but only clearly demonstrates we have a completely black body.
All objects have thermal radiation (as long as their temperature is above absolute zero, that is, -273.15 degrees Celsius), but no object is an ideal heat emitter. Some objects emit heat better, others worse, and all this depends on different conditions Wednesday. Therefore, a black body model is applied. Blackbody is ideal heat emitter... We can even see the color of a completely black body if it is heated, and the color we will see, will depend on before what temperature we heat up absolutely black body. We come close to such a concept as color temperature. Take a look at Figure 2.
Figure 2 - The color of an absolutely black body depending on the heating temperature.
A) There is an absolutely black body, we do not see it at all. Temperature 0 Kelvin (-273.15 degrees Celsius) - absolute zero, complete absence of any radiation.
b) We turn on the "super-powerful flame" and begin to heat up our absolutely black body. The body temperature, through heating, increased to 273K.
c) A little more time has passed and we already see a faint red glow of an absolutely black body. The temperature increased to 800K (527 ° C).
d) The temperature has risen to 1300K (1027 ° C), the body has acquired a bright red color. You can see the same glow color when heating some metals.
e) The body has heated up to 2000K (1727 ° C), which corresponds to the orange glow. Hot coals in a fire, some metals when heated, and a candle flame have the same color.
f) The temperature is already 2500K (2227 ° C). The glow of this temperature takes on yellow... It is extremely dangerous to touch such a body with your hands!
g) White color - 5500K (5227 ° C), the same color of the glow of the Sun at noon.
h) Blue color of the glow - 9000K (8727 ° C). In reality, it will be impossible to obtain such a temperature by heating with a flame. But such a temperature threshold is quite achievable in thermonuclear reactors, atomic explosions, and the temperature of stars in the universe can reach tens and hundreds of thousands of Kelvin. We can only see the same blue tint of light, for example, in led lights, celestial bodies or other light sources. The color of the sky in clear weather is about the same color. To summarize all of the above, you can give a clear definition of color temperature. Colour temperature is the temperature of a blackbody at which it emits radiation of the same color tone as the radiation in question. Simply put, a temperature of 5000K is a color that takes on an absolutely black body when it is heated to 5000K. The color temperature of orange is 2000K, which means that an absolutely black body must be heated to a temperature of 2000K in order for it to acquire Orange color glow.
But the glow color of a red-hot body does not always correspond to its temperature. If the flame gas stove in the kitchen is blue-blue, this does not mean that the flame temperature is over 9000K (8727 ° C). Molten iron in the liquid state has an orange-yellow tint of color, which in fact corresponds to its temperature, which is about 2000K (1727 ° C).
Color and its temperature
To imagine what it looks like in real life, consider the color temperature of some sources: xenon car lamps in Figure 3 and fluorescent lamps in Figure 4.
Figure 3 - Color temperature of xenon automotive lamps.
Figure 4 - Color temperature of fluorescent lamps.
On Wikipedia, I found numerical values for the color temperatures of common light sources:
800 K - the beginning of the visible dark red glow of incandescent bodies;
1500-2000 K - candle flame light;
2200 K - 40 W incandescent lamp;
2800 K - incandescent lamp 100 W (vacuum lamp);
3000 K - incandescent lamp 200 W, halogen lamp;
3200-3250 K - typical filming lamps;
3400 K - the sun is near the horizon;
4200 K - fluorescent lamp (warm white light);
4300-4500 K - morning sun and sun at lunchtime;
4500-5000 K - xenon arc lamp, electric arc;
5000 K - sun at noon;
5500-5600 K - photo flash;
5600-7000 K - fluorescent lamp;
6200 K - close to daylight;
6500 K - a standard source of daylight white light, close to midday sunlight, 6500-7500 K - cloudiness;
7500 K - daylight, with a large proportion of scattered from the clear blue sky;
7500-8500 K - twilight;
9500 K - blue cloudless sky on the north side before sunrise;
10,000 K - "infinite temperature" light source used in reef aquariums (actinium shade of blue);
15,000 K - clear blue sky in winter;
20,000 K - blue sky in polar latitudes.
The color temperature is source characteristic Sveta. Any color we see has a color temperature and it doesn't matter what color it is: red, crimson, yellow, purple, violet, green, white.
Works in the field of studying the thermal radiation of an absolutely black body belong to the founder of quantum physics, Max Planck. In 1931, at the VIII session of the International Commission on Illumination (ICE, in the literature it is often written as CIE) it was proposed color model XYZ. This model is a chromaticity diagram. The XYZ model is shown in Figure 5. 
Figure 5 - XYZ chromaticity diagram.
Numerical X and Y values define the color coordinates in the chart. The Z coordinate determines the brightness of the color, it is not used in this case, since the diagram is presented in two-dimensional form. But the most interesting thing in this figure is the Planck curve, which characterizes the color temperature of the colors on the chart. Let's take a closer look at Figure 6.
Figure 6 - Curve Planck
The Planck curve in this figure is slightly truncated and "slightly" inverted, but you can ignore this. To find out the color temperature of a color, you just need to extend the perpendicular line to the point of interest (area of color). The perpendicular line, in turn, characterizes such a concept as bias- the degree of color deviation in green or magenta. Those who have worked with RAW converters know such a parameter as Tint - this is the offset. Figure 7 shows the panel for adjusting the color temperature in such RAW converters as Nikon Capture NX and Adobe CameraRAW.
Figure 7- Panel for setting the color temperature for different converters.
It's time to see how the color temperature is determined not just for a single color, but for the entire photograph as a whole. Take, for example, a rural landscape on a clear, sunny afternoon. Who has practical experience in photography, he knows that the color temperature on a sunny afternoon is about 5500K. But few people know where this figure came from. 5500K is the color temperature the whole scene, i.e. the entire image under consideration (picture, surrounding space, surface area). Naturally, the image consists of individual colors, and each color has its own color temperature. What happens: blue sky (12000K), foliage of trees in the shade (6000K), grass in a clearing (2000K), various kinds of vegetation (3200K - 4200K). As a result, the color temperature of the entire image will be equal to the average value of all these areas, i.e. 5500K. Figure 8 clearly demonstrates this.
Figure 8 - Calculation of the color temperature of a scene shot on a sunny day.
The following example is illustrated in Figure 9.
Figure 9 - Calculation of the color temperature of a scene filmed at sunset.
The picture shows a red flower bud, which seems to grow from wheat groats. The picture was taken in the summer at 22:30, when the sun was going down. This image is dominated by a large number of colors in yellow and orange color tones, although there is also a blue tint in the background with a color temperature of about 8500K, there is also an almost pure white color with a temperature of 5500K. I took only 5 of the most basic colors in this image, compared them to the chromaticity diagram and calculated the average color temperature of the entire scene. This, of course, is approximately, but it is true. There are 272,816 colors in this image in total, and each color has its own color temperature, if we calculate the average for all colors manually, then in a couple of months we will be able to get a value that is even more accurate than I calculated. Or you can write a program to calculate and get an answer much faster. Going further: Figure 10.
Figure 10 - Calculation of the color temperature of other light sources
The hosts of the show decided not to burden us with color temperature calculations and made only two sources of illumination: a spotlight emitting white-green bright light and a searchlight that shines with a red light, and the whole thing was diluted with smoke ... and, well, yes - and put the presenter in the foreground. The smoke is transparent, therefore it easily transmits the red light of the searchlight and becomes red itself, and the temperature of our red color, according to the diagram, is 900K. The temperature of the second floodlight is 5700K. The average between them is 3300K. The rest of the image areas can be ignored - they are almost black, and this color does not even fall on the Planck curve in the diagram, because the visible radiation of incandescent bodies starts at about 800K (red). Purely theoretically, one can assume and even calculate the temperature for dark colors, but its value will be negligible compared to the same 5700K.
And the last image is in Figure 11.
Figure 11 - Calculation of the color temperature of the scene filmed in the evening.
Photo taken summer evening after sunset. The color temperature of the sky is located in the area of the blue color tone on the diagram, which, according to the Planck curve, corresponds to a temperature of about 17000K. Green coastal vegetation has a color temperature of about 5000K, and sand with algae has a color temperature of about 3200K. The average value of all these temperatures is approximately 8400K.
White balance
White balance settings are especially familiar to hobbyists and professionals alike in video and photography. In the menu of every, even the simplest soap dish-camera, it is possible to adjust this parameter. The icons for the white balance adjustment modes look something like the one shown in Figure 12.
Figure 12 - Modes of setting the white balance in the camera (video camera).
It should be said right away that the white color of objects can be obtained if use source Sveta with color temperature 5500K(it can be sunlight, a photo flash, other artificial illuminators) and if the considered objects white(reflect all visible light emission). In other cases, white can only be close to white. Take a look at Figure 13. It shows the same XYZ chromaticity diagram that we looked at recently, with a white point marked with a cross in the center of the diagram.
Figure 13 - White point.
The marked point has a color temperature of 5500K and, like true white, it is the sum of all the colors of the spectrum. Its coordinates are x = 0.33 and y = 0.33. This point is called point of equal energies... The point is white. Naturally, if the color temperature of the light source is 2700K, there is no white point here and there, what kind of white color can we talk about? There will never be white flowers! In this case, only highlights can be white. An example of such a case is shown in Figure 14.
Figure 14 - Different color temperatures.
White balance Is setting the value color temperature for the whole image. At correct installation you will get colors that match the image you see. If the resulting image is dominated by unnatural blue and cyan color tones, it means that the colors are "not hot enough", the color temperature of the scene is set too low, and you need to raise it. If the whole picture is dominated by a red tone - the colors are "overheated", set too heat, you need to lower it. An example of this is Figure 15.
Figure 15 - Example of correct and incorrect color temperature setting
The color temperature of the entire scene is calculated as average temperature all colors this image, so in the case of mixed light sources or very different color tones, the camera will calculate the average temperature, which is not always correct.
An example of one such incorrect calculation is shown in Figure 16.
Figure 16 - Inevitable inaccuracy in setting the color temperature
The camera is not able to perceive the sharply different brightness of individual image elements and their color temperature in the same way as human vision. Therefore, in order to make the image almost the same as you saw during shooting, you will have to manually adjust it according to your visual perception.
This article is more intended for those who are not yet familiar with the concept of color temperature and would like to learn more. The article does not contain complex mathematical formulas and precise definitions of some physical terms. Thanks to your comments, which you wrote in the comments, I made small corrections to some paragraphs of the article. I am sorry for the inaccuracies.
One of the important characteristics of any artificial light source is the color temperature (T c). Speaking simple language, this parameter indicates whether the light shade is warm and yellowish, neutral white or bluish cold. The glow color of LED lamps, unlike other types of lamps, can be much more wide range values. That is why the T c parameter is given special importance in LED-based light bulbs.
unit of measurement
From the point of view of physics, the color temperature (T c) characterizes the intensity of radiation of the light source in the operating frequency spectrum and functionally depends on the wavelength. It affects color perception by the human eye of illuminated objects. It is measured in degrees Kelvin (° K).
In some cases, the value in mirads (M) is used as a more convenient value. Mired, or inverse microdegree, is equal to one million divided by the value of Tc in kelvin.
The temperature of the light shade of LEDs used in general and auxiliary lighting fixtures is set using a phosphor layer. The method of applying the phosphor, chemical composition and its layer thickness are the determining factors for the future color and luminance performance of an LED lamp.
SP 52.13330.2011
The color of any physical body is determined by its spectral composition and the nature of the illumination that affects it. This means that when illuminating the same item with LED bulbs at different color temperatures, the item will have different shades. In order to set certain standards, SP 52.13330.2011 "Natural and artificial lighting" was developed.
SP 52.13330.2011 is an updated version of SNiP 23-05-95, valid in Russia until May 20, 2011.
SP 52.13330.2011 establishes standards for all types of lighting used in buildings and structures, in production and in open areas. Regarding the color of light, the document provides for the use of artificial sources, the color temperature of which should not go beyond 2400-6800 ° K.
In addition to a number of rules and regulations, SP 52.13330.2011 provides recommendations on lighting different types premises. For example, in living quarters, it is recommended to use warm, yellowish light temperatures that create a cozy atmosphere, and in work areas, colder ones, which contribute to the work atmosphere.
The importance and selection of the correct light shade
It is scientifically proven that the shade of light affects psychological impact space and is able to significantly change perception appearance illuminated items. And it has also been proven that choosing the right light temperature can have a beneficial effect on human behavior. For example, in a jewelry store, a well-chosen shade of backlighting accentuates the beauty of the product and promotes sales.
The color temperature of LED lamps directly affects the comfort in the illuminated room. By the value of T with all LED lamps it is customary to divide into 3 groups:
- warm glow 2700–3500 ° K;
- neutral glow 3500–5300 ° K;
- cold glow 5300–6800 ° K.
Warm color LED bulbs are ideal for home and lighting living rooms as their light is the least irritating to the eyes. Warm colors give objects a yellowish tone and create an atmosphere of the evening time. It should be noted that LED lamps with a warm glow are indispensable for organizing lighting in recreation areas.
Neutral light is applied in lighting industrial premises and offices. LED lamps with T c = 4000-4500 ° K contribute to increased efficiency, as proven by practical research. A further increase in the color temperature with the transition to the cold region leads to severe fatigue and nervous overstrain. Within an apartment, LED lamps of neutral light can also be used:
- as the main bathroom lighting;
- v table lamps designed to illuminate the workplace of students;
- in the kitchen at the place of food preparation.
LED lamps with T> 5300 ° K can only be installed in non-residential premises and at workplaces where high concentration of attention is required for a short time. In addition, they are effectively used in emergency lighting.
In conclusion, once again, it is worth noting that the color temperature of LED lamps is important characteristic, for the selection of which there are many tables. But choosing an LED lamp only by the parameter of the light shade is definitely not worth it. Right choice possible only with all technical features.
Read the same 
