It’s no secret that video cameras measure light in Kelvin, but you might be wondering why they do so. The reason is that a Kelvin (K) is actually a unit of measurement for color temperature. In other words, it’s a way of measuring the color spectrum of light waves that are being emitted from an object.
If you were to look at a camera’s color settings, Kelvin is the temperature in degrees Kelvin that you want the camera to be set to. So why do video cameras measure colors in Kelvin?
The short answer is that it’s all about how we perceive color. And while there are other ways of measuring colors on video cameras, if you intend to duplicate natural daylight as closely as possible, use the Kelvin scale.
The main thing is that natural daylight (sunlight) has a color temperature of 5400K (kelvins). Though a bit on the blue side, this is perfect for the human eye to see as much color as possible. The sunlight’s hotness gives the sky its blue color and causes other objects to appear white.
Depending on lighting situations, most people perceive objects under tungsten (“normal”) light as having a yellow cast. Does it sound a little confusing still!
As a beginner, please learn as much as possible about Kelvins rather than the mere reason. It would not only put you at an advantage but also make you better videos.
So after you have read the full article, by the end of it, you will have answers to all your million-dollar questions like –
What is the Kelvin value?
How do you use Kelvin for temperature?
What is the best color temperature for video?
When it comes to 3200k vs. 5600k lighting, which one carries the day?
Why is the white balance based on Kelvin?
What Color temperature is daylight?
Is there an app to measure Kelvin?
So, Why do video cameras measure colors in Kelvin? For a 360 degree view of that, read on!
What Is The Kelvin Value?
The degree to which you can specify the color of light is determined by a measurement called “Kelvin” (K), named after the physicist Lord Kelvin. In essence, that tells us how much of the high-frequency components in a particular light source will contribute to the appearance of color in our view. It was proposed in 1848 by William Thompson, who later became 1st Baron Kelvin of Largs (1824-1907)
The Kelvin scale is far more accurate than the Fahrenheit and Celsius scales of measurement. A temperature of 273 kelvin is subdivided by 1 kelvin as 273 degrees Fahrenheit or 273 degrees Celsius.
The absolute temperature at which no molecular motion can occur in a substance is 0K. The use of Kelvin makes it possible to measure the difference in temperature from absolute zero.
It has similarities with other temperature units, such as its scale determinant. The water freezing point and water boiling point determine their range. Going by that, Kelvin’s temperature scale is 273.16K to 373.16K.
Kelvin’s value has several uses, mainly because it doesn’t use negative numbers. For instance, it comes in handy when measuring the temperatures of liquids of nitrogen and helium, which are usually relatively low. The lack of negative numbers makes it easy to calculate the difference between two temperatures, no matter how big it might be. The kelvin value also comes in when carrying out some engineering applications.
Nevertheless, in the world of videography and photography, you will use the kelvin value to determine the color temperature.
Why Do Video Cameras Measure Colors In Kelvin?
What Thomson observed was – As the carbon became hotter, its color kept changing. It was initially black, then quite red, and kept switching to other colors with an increase in temperature until it started being relatively blue. It led to the development of a kelvin scale based on the hue of various colors. That’s why Kelvin is the unit used to measure the color temperature.
If you are in the film and television industries, you will need to know about measuring the color of light in the world. In video cameras, they count Kelvin as a way to describe color temperature or white balance. It is because different camera settings create different colors that appear suitable for specific purposes. You can see this in any professional photography or videography setup.
The video camera measures Kelvin as a way to describe the color of the light. For example, if you are shooting under blue fluorescent lights, you will know that it is around 5200k to 6500k. If you are shooting with HMI Lights, you can tell that they run in a range from 2700k-4100k depending on the light’s temperature.
Measurement of color temperature by kelvins on video cameras is essential because it helps define what will work best in camera-based work. If you have unique settings, then you can use them for specific tasks.
There are various sources of light, and every one of them has a different color temperature. Let’s talk more about them in the context of videography.
Components of Light/Color
It is okay to use color and light interchangeably sometimes. Light is one significant determinant of the color of a particular object. Several factors of light determine the color of an item. One of them is the color of light, which differs from one source to the other.
The object’s material also plays a massive role in determining its color, mainly based on how light reflects on it.
As a videographer, you can use the factors to manipulate the final color of an object. You achieve that using a white balance.
However, understanding how to manipulate the color best requires you to understand its various components.
They include Color Temperature, Hue, Value, and Chroma.
1. Color Hue
Besides different shades of colors, there are the original ones that form the rainbow. They have a relationship with this color component. The hue is the wavelength of light concerning the natural color spectrum—for example, a red car.
2. Color Chroma
As for Chroma, it refers to the saturation of a particular color. How strong is it? It is determined and affected by the addition of white or black to the original color. Great examples are royal blue and deep red, which are the Chroma of their respective colors.
3. Color Value
While the Chroma is about the strength and saturation of a color, value is about the darkness or lightness. The primary determinant of the color value is its light reflection.
4. Color Temperature
On the other hand, the color temperature is about how warm or cool the color hue is. It determines how the camera will see the white color, and all the other colors follow suit. It differs from the light of one source to the other.
That explains why fluorescents are white, whereas streetlights are orange. With this definition, it is now clear how color and temperature can appear in the same sentence in videography.
How Do You Use Kelvin For Color Temperature?
Now, one has an understanding of what color temperature is all about. It is clear that even when it comes to videography, Kelvin is the unit of measuring light’s temperature, often referred to as color temperature.
Experts often refer to it as white-hot, red hot, and painting with light, among other cinematography and still photography names. Besides, the color temperature differs from one Kelvin value to the other.
After all, the color corresponds to that of burning carbon at any particular temperature. Choosing an absolute Kelvin value is a way of adjusting the white balance of your camera manually.
You can adjust the Kelvin scale depending on the lighting you are looking for, no doubt. However, you ought to choose the value wisely since lighting helps determine how a scene looks.
As a videographer, you need to know a few things about the Kelvin scale. As the K value moves towards 0, which is the lowest value, the color becomes redder.
A good example is a candle flame and a lit match. Its range in terms of Kelvin is from 1000 K and 1900 K.
On the other hand, as the K value increases, the light color continues to change. The light’s color progresses as the K value gets higher to yellow, then white, and even blue.
For example, Halogen lights and Incandescent lights are usually 2500 K to 3000 K.
The 4800 K value represents sunlight, whereas 5600 K is around where daylight lies. When the sky is cloudy or cool white, the value can be anywhere between 6000 K and 7500 K. On the other hand, if it is clear blue, the Kelvin value is usually 10000 K. The Blue and Green colors seen to us are close to being in a range of 6000K.
Evidently, the higher the Kelvin value, the more blue the color, and the lower the Kelvin value, the more red the color is.
The chart below shows the range of colors and their corresponding kelvins.
Why Warm To Cool And Not Vice Versa?
Surprisingly, when the temperature increases towards high temperatures. Color temperature changes from warm to cool. Given the literal meaning of warm and cool, that doesn’t make much sense. However, the choice of words has nothing to do with the temperature.
Instead, it is more about human conception. As much as the blue color is recorded when the temperatures are high, it is associated with cool things such as snow and ice on most occasions.
On the other hand, people often associate warm things like flames and campfire with the red color.
What Is The Best Color Temperature For Video?
When choosing the most suitable color temperature, many factors matter and one major factor are how you want the scene to play out.
When it comes to films and videos, the typical color temperatures are 5600 K and 3200 K for daylight and tungsten. However, they may not always be the best, especially if there are mixed light sources or some light sources.
The list of sources is long. However, as much as there are many types of lightings, some are more common than others. Our focus will be those commonly used in videography.
Below are some of the lightings and their corresponding color temperatures.
Light Emitting Diodes (LED)
The Kelvin value for LED is in the range of 3000 K and 5600 K. As far as small sets are concerned, the popularity of LED is indisputable. After all, it is quite an excellent choice for anyone working with a tight budget.
As much as LEDs come in different colors, the most common are the White ones. Despite their output being limited, they are quite efficient and provide directional light. The lighting is also even and soft. They quickly move along the color spectrum, and you can also dim them if a need arises.
Tungsten
The Kelvin value is approximately 3200 K. Their color temperature is almost similar to that of average household light bulbs, but tungsten is more powerful. Since they are dimmable, you adjust them according to how you want the scene to look on the video.
Other than getting quite hot and requiring a lot of power, everything else is fine. If you plan to record indoor coverage, they won’t disappoint. Upon adding blue gel, it changes from tungsten lights to daylight.
Fluorescent
Their Kelvin value can be anything between 2700 K and 6500 K. It is what you go for if you want to replicate the scene of a dull and cloudy day, usually foggy but white.
Videographers love it because of the neutral glow and clear white light, especially in the range of 4000 K and 4500 K. Fluorescent lights work similarly to softboxes.
Smart Bulbs
Smart bulbs are usually preferred because it is possible to adjust their color temperatures. Therefore, if you are dealing with two different light sources, it is possible to change your smart bulb color temperature to match the color of the other sources.
Consequently, dealing with mixed color temperature complications has become a thing of the past.
HMI
Its color temperature is similar to that of natural daylight since it is approximately 5600 K. That would explain why Hydrargyrum Medium-Arc Iodide (HMI) lights are standard when setting most sets’ lighting. The blue hue, coupled with ultraviolet light, makes it impressive.
However, they can be pretty noisy when powering them, which is why a videographer should always notify the crew and cast members before doing it. When used together with ballasts, you can expect no flickering. Despite being relatively expensive, they are worth every penny.
Gels
It comes in handy when there are mixed color temperatures. These transparent plastic sheets come in different colors.
They are not really sources of light, but they have a way of changing a particular source’s color temperature. They are the best solution to mixed color temperatures, especially if they are clashing.
Different summary of various light sources and their estimated color temperatures:
- 1700 K – Match flame and low-pressure sodium lamps
- 1850 K – Candle flame, sunrise, and sunset
- 2400 K – Typical incandescent lamps
- 2550 K – Incandescent lamps (soft white)
- 2700 K – Fluorescent and LED lamps (Soft white compact)
- 3000 K – Fluorescent and LED lamps (Warm white compact)
- 3200 K – Photofloods and Studio lamps
- 3350 K – Studio “CP” light
- 5000 K – Horizon daylight
- 5000 K – Cool white/daylight, Tubular fluorescent lamps or compact fluorescent lamps (CFL)
- 5500 – 6000 K – Electric flash and Vertical daylight
- 6200 K – Xenon short-arc lamp
- 6500 K – Overcast and Daylight
- 6500 – 9500 K – CRT and LCD screen
- 15,000 – 27,000 K – Clear blue sky
3200k Vs. 5600k Lighting? Which One is Best?
The 3200k lights are warm yellow or orange, and the 5600k lights are bluer or daylight. It is because the color of the light corresponds to the Kelvin scale. The 3200K light is for an indoor scene, and 5600K is for an outdoor setting.
For instance, when filming indoors with window light, it’s hard to decide which type of light should be used. Choosing either would depend on what scenes you want in your video.
If you’re filming inside- then use tungsten lamps or lampstands. If you’re filming outside- use 5600k lamps like LED panels or a backlight as well as gels to simulate 3200K indoors.
By the way, when the color temperature is higher than 5500K, it becomes difficult to use on indoor scenes. After all, it resembles a light bulb.
Going by the Kelvin scale, most video lights range between 3200K and 5600K. Since the 3200K and 5600K are the most common color temperatures in the video, it might be a daunting task to decide one better than the other.
The former lights are usually warm, whereas the latter ones are obviously warm. You can equate the 3200K with tungsten lights and the 5600K with the daylight for the LED panels. So, if you are lighting a scene, which one of the two should you go for then?
The truth is that there is no definite answer as to whether to go for 3200k or 5600k. On the contrary, either of the Kelvins can be the most suitable, depending on the scene.
For instance, 3200K is ideal for an indoor scene since its color is warm yellow or orange. You can set it up in various ways, including the use of light fixtures, lampstands and tungsten desk lamps. Whether the videographer casts the warm light on a scene’s part of the subject’s face, the results will be impressive.}
On the other hand, 5600k lighting gives your scene an outdoor feel. It is usually bluer, resembles daylight in the middle of the day, and makes a scene look cool. It has a way of making a scene look pretty cinematic. It also comes in handy when you want to fake sunlight.
It has a way of making a scene look like sunlight entering through the window and illuminating the subject. So, don’t hesitate to settle for it for the backlight.
The bottom line is that the scene that you want will determine the lighting that you choose. Fortunately, once you decide, all you have to do is adjust your camera’s white balance.
Nevertheless, there are some exceptions, especially when the scene is indoor. A good scenario is if you want to film indoors, but there is outdoor light entering through the window. It yields a mixed color temperature scenario, making it impossible to select a specific color temperature setting.
Photo by Mikhail Nilov from Pexels
That’s where a videographer makes a formidable choice of which one to keep and the one to discard. If you choose the outdoor scene, you can find gels to make the indoor 3200k light look like the outdoor 5600k light.
On the other hand, if you settle for the indoor light, you can use black velour or duvetyn to block the outdoor light. After all, maintaining the same color temperature for the entire scene is usually advisable.
Why Is The White Balance in Video-Based On Kelvin?
Do you know when you’ve got that awful orange tint, or you have an overly blue hue? That all comes back to the white balance on your camera. White balance is a setting that tells the camera what color temperature to use while shooting. It means how much yellow or blue the light is.
Why is white balance important?
The thing is, before, we were talking about how color can affect your videos, but now we’re here to talk about how it can ruin your videos. It is especially vital for professional videos.
So why is the white balance in the video based on Kelvin? Well, it is a way to measure the temperature of the color of light. A higher Kelvin number means cooler light. A lower Kelvin number means warmer light.
White balance is related to color temperature. After all, the former refers to balancing the latter of an image. When achieving the balance, white balance means adding a color that is the opposite of the captured but equal. That’s where the balance comes in and result in a relatively neutral coverage.
So, since the units of color temperature are Kelvin, it goes without saying that the same unit should apply to the white balance. Otherwise, how easy will it be to add a corresponding amount of the opposite color if the companies are different?
What Color Temperature Is Daylight?
There is no definite answer to the question as it differs based on several factors, including direction, weather conditions, and time. Therefore, daylight’s color temperature can be 3500 K if it is time that photographers call the golden hour. It can also be as low as 200 K when the sun is either rising or setting.
If the sky is cloudy, the color temperature can range from 6000 K to 7500 K. In most cases; it is usually 5600 K at midday. It can also be as high as 10,000 K when it comes to the north light.
Under such a circumstance, the light is natural but doesn’t come from direct sunshine. Instead, it comes from the north, usually when the sky is blue. Artists love the north light when it comes to studios. In most cases, the light enters a room from a window that is facing north.
Is There An App To Measure Kelvin?
Interestingly, technology isn’t disappointing, even when it comes to color temperature. There are apps at your disposal if you want to measure Kelvin.
There are a lot of applications that measure Kelvin on mobile phones such as Android and the iPhone.
These applications are listed below.
- 1) Kelvin: This application is only for Android and can be downloaded from here. It costs $2.99 and has a 4-star review on the Google Play store. Kelvin uses your phone’s camera meter to measure light intensity in Kelvin.
- 2) iKelvin Meter: This application is also for Android and can be downloaded from here, and it costs $0.99 from the Google Play Store. This app measures light in Kelvin while using your phone’s camera to monitor the light’s brightness.
- 3) Light Sensor – Light meter: This application is only for Android and can be downloaded from here; it costs $0.99 and has a 5-star rating on the Google Play store.
- 4) 4 Hue: A good option for an Android user is all 4 hue. What you need to do is select the light that you intend to figure out its color temperature. Then, tap of select color temperature. It gives you an option to click somewhere and then enter a color temperature.
- 5) Kelvin Meter: This application is only for Android and can be downloaded from here; it costs $0.99 and has a 3-star rating on the Google Play store. The application measures light intensity in Kelvins while using your phone’s camera to monitor light(s) brightness.
- 6) IKilnometer: This application is only for Android and can be downloaded from here; it costs $1.99 and has a 2-star rating on the Google Play store. The application measures light in Kelvin while using your phone’s compass to view the direction of lights or measure the distance between lights.
Android users also have iConnectHues and Hue Essentials. On the other hand, those using iOS can settle for Hue Lights.
Final Words
Now you know why the video cameras measure colors in Kelvin. Initially, you may have found it strange that there is any connection between color and Kelvin, but now the relationship is clear.
The consequences of choosing the wrong color temperature can ruin your video quality and appearance, so make sure to know about these issues beforehand.
It also determines what exposure you set on the camera to capture true-to-life colors. If you know about these factors beforehand, you can adjust accordingly and become a thorough professional in shooting videos.
