The Color Temperature Paradox

If you take a piece of white paper into different lighting conditions, it will be an objectively different color in each situation, but our brains are clever enough to make us feel like it's still white - it's still the same piece of paper, after all. To match our experience, cameras have to do this, too, "balancing" the colors of an image so that a white object looks white under a given light, rather than some other color. And the typical unit to measure the color of a light is the Kelvin. Which is weird, because Kelvin is a unit for measuring temperature, not color. What temperature and the color in a photograph have to do with each other comes down to history and physics.


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[rtg_onefourtwoeightfiveseven]

I'm an astrophysicist and we deal with the idea that 'red = cold, blue = hot' all the time. I've (jokingly) suggested that we should swap labels on the department's taps so that the red tap is cold and the blue is hot.

[caynebyron]

During the Australian forest fires of 2020, one day everything went orange, like going outside was like being in a movie set in Mexico. But you couldn't take photos of it with your phone because the camera would auto colour correct.

[Michaelonyoutub]

Another point for confusion for people who have experienced the many different lighting technologies we have had over the years, incandescent lights which produce a "warm" orange yellow light, also give off a lot of heat, while some of the alternatives to incandescent, which often gave off "colder" blue or white lights, often gave off much less heat. This adds to the image people have of orange/yellow being warm, and blue/white being cold in our minds.

[KnowArt]

good stuff! never occurred to me that "warm light" and "cool light" are the wrong way around

[WackoMcGoose]

As a Home Depot employee that constantly has to explain color temperature of light bulbs, this was quite informative. Also I'm really thankful we have a "selectabulb" demo unit to show customers what different color temps look like, plus color-coded packaging so once they know what color they want, I can just point them to the right shelf and bay and they're good to go.

[ToyKeeper]

It doesn't need to be called color temperature compensation... "white balance" is a shorter and more intuitive term which is already in widespread use and covers both CCT and duv and other types of adjustments.

[wile]

3:15 no one calls it color temperature, we all call it white balance, which accurately reflects what you explained here lol

[RanOutOfSpac]

This concept really screwed with me badly when I was young artist. Learning blue=hot before color temperature in painting confused me for the longest time even though it really shouldn’t have.

[Skarix]

As someone who went from a science kid to a filmmaker, this is by far one of the most frustrating things I had to learn. “Cold” colors, expressed in HIGHER temperature (warmer) numbers is achieved by LOWERING the camera temperature setting and forcing it to expect warmer light, which is achieved with cooler temperatures.

It becomes intuitive once you’ve dealt with it long enough, but this single-handedly convinced me to stay away from lighting and just let someone else handle it!

[Kilomylesco]

One thing you missed was how the camera “knows” what “white” is in the first place which is done by looking for Middle Grey or 18% grey!

[Gna-rnzx]

I was hoping this video would be about why we colloquially think red is warm and blue is cold.

[kyoopihd]

Ice and deep water can appear blue because of the way they absorb and scatter light. Fire looks red. Maybe some evolutionary intuition there? Cool video.

[isacami]

i thought the paradox was that ice looks blue so we call that cold light and fire is obviously red~orange, so we call that warm

[toastbrot]

3:22 we call it whitebalance. Because you're balancin the white according to the surrounding light. So if you're stting the camera to 2500k you're balancing the white to a 2500k light. Makes perfect sens if you phrase it like that imo.

[davidli]

One thing to mention is that while balance is not just to align the image to what we see. Otherwise, our eyes should be able to adjust to the image just as we adjust to the light -- at least viewing the screen in a dark room. White balance is also there because the whitest part of the image is fixed color temperature. For example, the overexposed part of the screen (i.e all RGB channels are 100%) should have a fixed color temp (say 6300k). This will differ from the part that is not over exposed. This is why white balance is less of an issue in HDR photos/videos.

[TopLieutenant]

Wait, that's not a paradox... that's just mildly confusing if you don't understand.

[Novastar.SaberCombat]

That was one CONFUSING way to express that humans are used to reds and oranges feeling "hot" (mostly because of sunshine), and violets and blues feeling "cold" because of darkness and night. It's as much a visual anomaly as it is a sense of touch or whatever.

[seraphin]

as a photographer who has to deal with color temperature all the time: at first it was disconcerting.. and after more than 20 years.. it still is!
The fact that we still call a warm tone, a tone that is much lower than the blue tone.. *brain pops out*
But this video helped at least <3

[Whawpenshaw]

i feel like the word "paradox" is thrown around a bit liberally here.

[beneisen]

I always tell my students that they shouldn't say "degrees Kelvin" but people know what you mean if you say "degrees Kelvin." Points to "A Brief History of Everything, feat. Neil deGrasse Tyson" video on this channel. But thanks for another good explanation video.