Understanding Kelvin in Lighting (Color Temperature)

December 27, 2023

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Understanding how the Kelvin scale applies to lighting is key to improving your photography and telling more compelling stories.

This article is a comprehensive guide designed to help photographers use color temperature to their advantage.

Don’t worry – I won’t go too deep into physics. I’ll keep things simple and practical so you can apply what you learn in your photography right away.

If you’ve ever wondered what the Kelvin temperature on a light bulb means or why your photographs have an undesired color cast, you’ll find the answer here.

You’ll also learn how to choose the best type of light for your photographs, how to set the custom WB on your camera using Kelvin degrees, and other useful tips.

What Is Kelvin in Lighting?

Kelvin (K) is the unit of measurement for thermodynamic temperature. In lighting, what you measure with the kelvin scales is the colour temperature of a given light.

This is based on the formula of Planck’s law defined by German physicist Max Planck in the 1900s.

Without going too deep into physics or math, the formula describes the color of the radiation emitted by a theoretical black body at a certain temperature.

The Kelvin scale in lighting goes from 1,000-10,000K, and its correlated color temperature goes from red to blue.

What Is Color Temperature?

Color temperature is the concept that defines the color of visible light. In the middle of the Kelvin scale, there’s what we consider white light.

Lower temperatures on the scale correspond to warm colors. These are emitted by fire, tungsten light bulbs, daylight around the golden hour, etc.

High temperatures indicate blue light – in other words, cool colors.

The perceived color and its correlated color temperature can seem counterintuitive because high temperatures give cool colors and vice-versa.

As mentioned before, this derives from a temperature scale originally based on the color emitted by an ideal black body radiator.

As the temperature of the black body radiation increased, it would change colors from red to yellow to white to blue.

How Does Color Temperature Affect Photography?

Photo credit: Artem Podrez

Color temperature is extremely important in photography both as a technical aspect and as a creative tool.

On the technical side, the color temperature helps us to capture what we’re seeing accurately.

All lights have a different color temperature. However, our brains automatically do a color balance so that the color cast doesn’t bother us.

In contrast, the camera registers the color of light as it is – unless you tell it otherwise. If you don’t adjust the WB on your camera to match the color temperature of the available light, the photo will seem a little off.

This affects things that we know are supposed to be white, changes the skin tone, etc.

On the creative side, color temperature helps us to create an atmosphere.

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The most basic concept is that we’re culturally biased to interpret blue as cold because that’s how we see ice. Instead, red and orange are the colors of fire – so we associate them with warmth.

Many other variations of this also have to do with real life. If you go to a hospital, you’ll notice they always use cool white and bright white. So, we associate a certain location or a certain feeling with it.

The same happens with romantic restaurants that use warm, dim light and many other scenarios in everyday situations.

So, when we see a photograph with those color temperatures, our perception is shaped by all that previous knowledge. All of this happens on a subconscious level, of course.

Knowing this, a photographer can communicate a message or convey a feeling through color temperature.

In conclusion, color temperature affects photography in many ways. It can influence an image’s mood, ambiance, color rendition, and storytelling.

When photographers know how to manipulate color temperature, they can be more accurate, create more compelling narratives, and evoke emotions.

Also, consider that in digital photography, it’s possible to change the color temperature of a photograph with an editing program.

In most cases, you’ll find some basic tools, such as temperature and tint, to manipulate the WB. However, you’ll often find more complex tools to adjust the colors of the image until you set it to your liking.

What Is the Difference Between Lumens and Kelvin in Lighting?

Lumens is the measuring unit used to express the amount of light emitted by a given light source. In simpler words, Lumens tells you how bright a light is.

Higher lumens indicate a bright light, while lower lumens correspond to a dimmer light. This has nothing to do with the color of the light.

If you want to know how warm or cool a light is, then you have to check the Kelvin degrees. This is what indicates the color temperature of a light.

Lower Kelvin measurements correspond to a warmer color, while high Kelvin temperatures indicate a cool light. These have nothing to do with the intensity of the light.

Even if Lumens are usually used when talking about LED light bulbs, they are a unit of measurement used to quantify the brightness of any light source – regardless of its technology.

So, when you’re buying light sources – make sure you consider both the Lumens and the Kelvin temperature.

Advantages of Manually Setting Your White Balance in Kelvin

Let’s start by saying that using a custom WB gives you more control over your photo as opposed to using AWB or any of the presets.

Also, adjusting the WB before shooting is one less thing to think about when you’re editing. This rule applies to any manual setting vs. an auto feature of your camera.

However, some photographers prefer to take a test shot and use that to tell the camera to adjust the Kelvin degrees accordingly. Other photographers prefer to set the Kelvin degrees using the dial manually.

None of these methods is right or wrong – it’s simply a personal preference. However, the manual method gives you the flexibility to use the Kelvin scale creatively.

For example, you might know that 5650K is the correct color temperature for the LED light that you’re using. However, you might want a cooler or warmer light to set a particular mood.

Well, you can do this by manually changing the Kelvin degrees in your camera.

What Kelvin Color Temperature Photography Settings Should I Use?

The Kelvin color temperature you should use for your photographs depends on the light that you have on your scene and the mood you want to convey.

If you’re using artificial light such as flashes, strobes, or photographic LED lights, they’re usually daylight balanced.

This means that their color temperature will be between 5000K and 6500K. The manufacturers provide this number when you buy them. So, you can match the Kelvin color temperature setting to that value.

Other light sources have different color temperatures. Indoor lighting may be cool white in offices and warm white in households.

The light bulbs from table lamps often cast a warm yellow light – therefore, you should use a cooler color temperature to compensate.

However, the light appearance also helps you set the mood. So, you might want to leave the warm orange or yellow light as it is to create the atmosphere.

Generally speaking, it’s best to use a custom setting so that you have more control.

Kelvin Lighting Color Temperature Chart

Here’s a visual representation of the Kelvin scale with its different colors and how it’s applied to photography.

The Effects of Lighting Color on Skin Tone

Different temperatures affect how things look in a photograph.

Generally speaking, low color temperatures give the atmosphere an orange, yellow, or red tone. This enhances the skin’s warmer tones.

On the other hand, cooler color temperatures will accentuate the cooler tones of the skin, making the subject look paler.

Even when the camera’s white balance is set to the light color temperatures, the skin tone will look different according to the Kelvin temperature that you’re using.

The YouTube channel Tall Guy Films did a few test shots proving this. In them, you can see how the white wall behind the subject looks the same – however, his skin changes according to the various temperatures.

What Kelvin Is Best for Outdoor Photography?

Daylight is considered to have color temperatures between 5000 and 6500K. However, natural light changes color temperatures throughout the day and according to the weather conditions.

Therefore, there isn’t an exact number from the Kelvin scale that’s best for outdoor photography.

Also, the color temperature can be a creative tool used by photographers to create a certain atmosphere or convey a specific mood. So, the Kelvin degrees that you use will also depend on your creative vision.

FAQs About Kelvin Color Temperature

What does Kelvin color temperature mean?

The Kelvin scale is the way the color appearance of light is described. So, the Kelvin color temperature is the number of Kelvin degrees a light has, and it corresponds to a certain color.

For example, incandescent lamps usually have around 2700 kelvin degrees. So, they have a warm color light with an orange-yellow color temperature.

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What is the difference between 5000K and 6500K color temperature?

Both color temperatures are considered neutral daylight. However, 5000K is more common in flash and strobe lights, while 6500K is used for LED lights.

What is color temperature 4000K Kelvin?

A Kelvin temperature of 4000 refers to a cool white often used in the ceiling lights of offices or kitchens.

In photography, it is also used often when you have mixed lights – such as indoor light bulbs with warm color temperatures and higher color temperatures from the sunlight coming through the window.

What is the normal Kelvin temperature for photography?

Photographic lights are often daylight balanced to a color temperature that ranges from 5000 – 6500K. This could be considered “normal” to a degree.

However, both light bulbs and daylight can have different Kelvin temperatures. Plus, you might want to make adjustments based on creative decisions. So, there isn’t really a single “normal” temperature.

Is higher Kelvin more blue?

Yes. The higher you go in the Kelvin scale, the cooler color temperature a light has. This means that it will have a blue tone.

How hot is lighting in Kelvin?

A Kelvin temperature is not an actual temperature – in other words, it doesn’t relate to physical heat. Rather, it has to do with the light appearance of color. For example, you can talk about warm-colored light when it sits low on the Kelvin scale.

Why are high white balance temperatures redder when warmer objects are bluer?

The WB in photography is meant to compensate for any color hue in your images. When things look bluer than they should, you need to raise the WB temperatures to make the image look neutral white.

Warmer objects like candle flames emit light with low color temperatures, which appear redder to our eyes. However, if you use a high white balance temperature setting, the light’s cooler tone will counteract the warmth of the objects, making them appear bluer.