What is TV color temperature, and why does it matter?

Color temperature is a TV control that most never touch, but it's the key to making your TV as accurate as possible.

Color Temp
Screenshot: Geoffrey Morrison - Image: Touchstone
One of the least understood controls on nearly all modern televisions is the color temperature control.

Casual adjustment of this can result in the image appearing too red, or too blue. Setting this vital control correctly has a significant impact on the accuracy and performance of your TV.

A bit o' science

Before we can get into what the color temperature control does for a TV, we need to talk about color temperature itself.

A marble
A marble

Imagine an imaginary object. Hmmm, OK, forget that. Imagine a marble. A perfectly black marble. There's one over there >

It's black because it absorbs all light equally: green, blue, fuchsia, everything. If you were to heat this imaginary object, it would, in theory, emit all frequencies of light equally. Raise the temperature of the marble to a toasty 2,200 degrees Fahrenheit, and it will glow a lovely red. If you have a toaster, you've seen this before. As the coils warm up, they glow red.

If you were to increase the temperature even further, to say 11,000 degrees F, it would appear white. Keep going, past 17,000 degrees, it would look blue. It would also now double as a space heater that would sear your walls.

Of course such an idealized object, called a blackbody radiator, doesn't exist. Graphite comes pretty close, though. Also, Fahrenheit is merely a tool we in America use to confuse the world about how hot it gets in The Valley during the summer. So color temperature is in the more scientific Kelvin. Not that you'd ever need to convert it, but here's a Web site if you're curious.

The most confusing aspect of this, is that when an object has a higher color temperature, it is referred to as looking "cooler" due to its bluish nature. Conversely, an object with a lower color temperature is called "warmer" due to its reddish hue. You can see this with light bulbs. Most Lowe's/Home Depots have a wide variety of CFL bulbs that offer warmer or cooler color temperatures. There's often a display and everything to demo the different colors. FWIW I also buy the warmest I can, but that's just personal preference.

With televisions, the D6500 standard (as specified by the CIE) approximates daylight, and as its name suggests it's roughly 6,500 Kelvin. Turns out, this is kinda important.

One temperature to rule them all

It's vital that all stages in television production have a set color temperature. Without the D6500 standard, each camera could produce different colors. Imagine watching Craig, and each time they switched to a different camera (there are three), he'd look redder or bluer. Distracting to say the least, right? With scripted shows, the monitors used during the editing process need to match the cameras as well, otherwise more color inaccuracies could result.

There are more stages, but let's not muddle the point. In order to ensure that the show (or movie) has a consistent look and feel--one the director intends--all devices in the chain need to be set for the same color temperature.

So the question becomes, don't you want to watch it that way, too?

Adjustable color temperature: your gift, brought to you by TV reviewers

Ten years ago, very few TVs had user-adjustable color temperature. Now nearly all do. In part you can thank your favorite TV reviewers. We clamored for this control and likely got it to shut us up ('cause that works...). So now your TV can have a much more accurate color temperature.

The thing is, most people aren't used to an accurate color temperature. For decades, TV manufacturers have made their TVs exceedingly cool out of the box. Without knowing which individual TVs they shipped would end up in a store on display, they set every one to look good in this environment. It was easily documented that the brightest TV on the show floor would sell best (an adage that's still true, largely explaining LCD's popularity).

Thanks to some aspect of evolution beyond my hope of explaining, our brains perceive bluer TVs as brighter. Maybe it has something to do with Cro-Magnons only getting basic cable. Regardless, TV manufacturers made their TVs as bright and as blue as possible, in a peacock-like attempt to get your attention in Best Buy.

That this mode looked terrible in the home and was completely inaccurate concerned them little. Now, thanks to every TV being digital, adjusting the color temperature is as easy as a setting in a menu.

Perception

No matter how your TV's color temperature is set, it will look correct to you. Any change you make will make the TV appear "wrong." Allow me to demonstrate.

Color Temp differences
Note the color differences between the three images. See the text for the key. Screenshot: Geoffrey Morrison - Image: Touchstone
Take a close look at the image above. The top one looks red, the middle one looks OK, and the bottom looks really blue, right?

And now I will blow your mind.

If you've never adjusted your TV's color temperature, it is likely in the Cool/High color temp mode, and looks like the bottom image. Yep, your TV is blue.

These are photos of a projector in the 5,000K (top), calibrated D6500 (middle), and 9,000K color temp modes. Depending on your computer monitor, these images may not be as different as they could be nor an accurate representation of the actual color temperatures, but hopefully you'll get the general idea from the differences.

The center image is what the director and cinematographer intended for this scene: a typically overcast British morning pre-Vogon destruction. Notice how the bottom image seems like the weather is cooler? Maybe a winter morning? Notice how the grass's color is off as well. The top image seems a lot warmer, correct? Like it's a summer day? Also not what the director was intending.

There's pronounced impacts on skin tones and more as well.

Here's the big question, though: Do you care? If you were to set your TV to Warm or one of the middle settings, your first reaction is that it's going to look too red. This is because you're used to the blue image.

If you don't care, go ahead and leave it. The calibration police aren't going to knock on your door and demand you change your TV to a more accurate setting. But if you want an image more like what the director intended, switch to one of the warmer settings. Give it a day or two to allow your brain to adjust. If after a few days you want to go back, by all means. I'll warn you though, it's now going to look really blue.

Calibration

When you hear talk about calibrating a TV, primarily this is about color temperature. With specialized equipment, a calibrator can see what the most accurate mode your TV should be in, then go further and adjust the internal settings to make sure that bright images are the same color temperature as darker images (believe it or not, that's not a given). Is this service worth the few-hundred-dollar cost? I'll leave that for you. I will say that now that I'm used to a TV with accurate color temperature and accurate color points (a whole different article), I can't go back.

If you're interested in learning more about getting your TV calibrated, check out my What is HDTV calibration article.

Lastly, color temp is just one of the controls to make your TV look its best, if you're not going with a professional calibration (or even if you are), it's worth it to get one of the many decent setup discs .

You don't have to take my word for it:


Got a question for Geoff? First, check out all the other articles he's written on topics like HDMI cables , LED LCD vs. plasma , Active vs Passive 3D , and more. Still have a question? Send him an e-mail! He won't tell you what TV to buy, but he might use your letter in a future article. You can also send him a message on Twitter: @TechWriterGeoff.

About the author

Geoffrey Morrison is a freelance writer/photographer for CNET, Forbes, and TheWirecutter. He also writes for Sound&Vision magazine, HDGuru.com, and several others. He was Editor in Chief of Home Entertainment magazine and before that, Technical Editor of Home Theater magazine. He is NIST and ISF trained, and has a degree in Television/Radio from Ithaca College. His bestselling first novel, Undersea, is available in paperback and as an ebook on Amazon, B&N, and elsewhere.

 

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