It is correct to match light sources with the same color temperature?How does Kelvin for color temperature relate to Kelvin for actual temperature?Relationship between tint-temp and magenta-green-blue-amber white balance corrections?What is Colour Rendering Index (CRI)?Can I color-balance a photo if I know the light source within the photo?How can I adjust the colour temperature of an image programmatically?What color system best differentiates Yellow/Red/Black?Reducing color balance errors across multiple camerasHotshoe flash with adaptable color temperature?How do I measure the correlated color temperature of a light source with a DSLR without a gray card?How can I match adjustable-color artificial light temperature to ambient light?Do photographers see ambiguity in the color of the blue/black (gold/white) dress?Room color temperatureWhat would happen if a camera used entirely different primary colors?Why would a camera change colors on the image when producing JPEGs?

How seriously should I take size and weight limits of hand luggage?

Valid term from quadratic sequence?

Why would the Red Woman birth a shadow if she worshipped the Lord of the Light?

Extract rows of a table, that include less than x NULLs

How to show a landlord what we have in savings?

Arrow those variables!

Calculating entropy change: reversible vs irreversible process

Running Low on Limestone

Why didn't Miles's spider sense work before?

Unable to supress ligatures in headings which are set in Caps

One verb to replace 'be a member of' a club

How do I handle a potential work/personal life conflict as the manager of one of my friends?

What are some good books on Machine Learning and AI like Krugman, Wells and Graddy's "Essentials of Economics"

Mathematica command that allows it to read my intentions

Plagiarism or not?

Avoiding the "not like other girls" trope?

Assassin's bullet with mercury

How badly should I try to prevent a user from XSSing themselves?

Why do bosons tend to occupy the same state?

Alternative to sending password over mail?

Why was the shrinking from 8″ made only to 5.25″ and not smaller (4″ or less)?

What does the expression "A Mann!" means

Should I tell management that I intend to leave due to bad software development practices?

How do I deal with an unproductive colleague in a small company?



It is correct to match light sources with the same color temperature?


How does Kelvin for color temperature relate to Kelvin for actual temperature?Relationship between tint-temp and magenta-green-blue-amber white balance corrections?What is Colour Rendering Index (CRI)?Can I color-balance a photo if I know the light source within the photo?How can I adjust the colour temperature of an image programmatically?What color system best differentiates Yellow/Red/Black?Reducing color balance errors across multiple camerasHotshoe flash with adaptable color temperature?How do I measure the correlated color temperature of a light source with a DSLR without a gray card?How can I match adjustable-color artificial light temperature to ambient light?Do photographers see ambiguity in the color of the blue/black (gold/white) dress?Room color temperatureWhat would happen if a camera used entirely different primary colors?Why would a camera change colors on the image when producing JPEGs?













3















For example, the color temperature of a candle flame, sunrise and sunset have the same color temperature, knowing that its color temperature is the same, could you say that these sources are similar or equivalent? Could you say that they would produce the same picture of a scene? Could you say that the values of the pixels are the same with these three sources of light? Thanks in advance










share|improve this question









New contributor




SRG is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.















  • 3





    I mean, if you disregard the billion x difference in lumens...then yea, I suppose you could say they’re similar :-D jokes aside - this question seems unclear to me. What problem are you trying to solve?

    – Hueco
    2 days ago












  • s it possible to quantify the sun in lumens? I think the only thing I've seen is that you can quantify in luxes. This question is no joke, excuse my ignorance, I am a little new in this. The problem I am trying to solve is to relate artificial light sources and natural light sources and see if there is any similarity between them, the only similarity I could find was through the color temperature.

    – SRG
    2 days ago











  • An example of relating to sources of natural and artificial light that I could think was sunrise and sunset and some household lamps. The sunlight at sunrise and sunset have a temperature of 2400 ° K while some light bulbs have a temperature of 2800 ° K, these are values ​​that are a little close, I thought about relating. Is this correct?

    – SRG
    2 days ago















3















For example, the color temperature of a candle flame, sunrise and sunset have the same color temperature, knowing that its color temperature is the same, could you say that these sources are similar or equivalent? Could you say that they would produce the same picture of a scene? Could you say that the values of the pixels are the same with these three sources of light? Thanks in advance










share|improve this question









New contributor




SRG is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.















  • 3





    I mean, if you disregard the billion x difference in lumens...then yea, I suppose you could say they’re similar :-D jokes aside - this question seems unclear to me. What problem are you trying to solve?

    – Hueco
    2 days ago












  • s it possible to quantify the sun in lumens? I think the only thing I've seen is that you can quantify in luxes. This question is no joke, excuse my ignorance, I am a little new in this. The problem I am trying to solve is to relate artificial light sources and natural light sources and see if there is any similarity between them, the only similarity I could find was through the color temperature.

    – SRG
    2 days ago











  • An example of relating to sources of natural and artificial light that I could think was sunrise and sunset and some household lamps. The sunlight at sunrise and sunset have a temperature of 2400 ° K while some light bulbs have a temperature of 2800 ° K, these are values ​​that are a little close, I thought about relating. Is this correct?

    – SRG
    2 days ago













3












3








3








For example, the color temperature of a candle flame, sunrise and sunset have the same color temperature, knowing that its color temperature is the same, could you say that these sources are similar or equivalent? Could you say that they would produce the same picture of a scene? Could you say that the values of the pixels are the same with these three sources of light? Thanks in advance










share|improve this question









New contributor




SRG is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.












For example, the color temperature of a candle flame, sunrise and sunset have the same color temperature, knowing that its color temperature is the same, could you say that these sources are similar or equivalent? Could you say that they would produce the same picture of a scene? Could you say that the values of the pixels are the same with these three sources of light? Thanks in advance







color white-balance light image-processing






share|improve this question









New contributor




SRG is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.











share|improve this question









New contributor




SRG is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.









share|improve this question




share|improve this question








edited 2 days ago









mattdm

122k40357653




122k40357653






New contributor




SRG is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.









asked 2 days ago









SRGSRG

184




184




New contributor




SRG is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.





New contributor





SRG is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.






SRG is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.







  • 3





    I mean, if you disregard the billion x difference in lumens...then yea, I suppose you could say they’re similar :-D jokes aside - this question seems unclear to me. What problem are you trying to solve?

    – Hueco
    2 days ago












  • s it possible to quantify the sun in lumens? I think the only thing I've seen is that you can quantify in luxes. This question is no joke, excuse my ignorance, I am a little new in this. The problem I am trying to solve is to relate artificial light sources and natural light sources and see if there is any similarity between them, the only similarity I could find was through the color temperature.

    – SRG
    2 days ago











  • An example of relating to sources of natural and artificial light that I could think was sunrise and sunset and some household lamps. The sunlight at sunrise and sunset have a temperature of 2400 ° K while some light bulbs have a temperature of 2800 ° K, these are values ​​that are a little close, I thought about relating. Is this correct?

    – SRG
    2 days ago












  • 3





    I mean, if you disregard the billion x difference in lumens...then yea, I suppose you could say they’re similar :-D jokes aside - this question seems unclear to me. What problem are you trying to solve?

    – Hueco
    2 days ago












  • s it possible to quantify the sun in lumens? I think the only thing I've seen is that you can quantify in luxes. This question is no joke, excuse my ignorance, I am a little new in this. The problem I am trying to solve is to relate artificial light sources and natural light sources and see if there is any similarity between them, the only similarity I could find was through the color temperature.

    – SRG
    2 days ago











  • An example of relating to sources of natural and artificial light that I could think was sunrise and sunset and some household lamps. The sunlight at sunrise and sunset have a temperature of 2400 ° K while some light bulbs have a temperature of 2800 ° K, these are values ​​that are a little close, I thought about relating. Is this correct?

    – SRG
    2 days ago







3




3





I mean, if you disregard the billion x difference in lumens...then yea, I suppose you could say they’re similar :-D jokes aside - this question seems unclear to me. What problem are you trying to solve?

– Hueco
2 days ago






I mean, if you disregard the billion x difference in lumens...then yea, I suppose you could say they’re similar :-D jokes aside - this question seems unclear to me. What problem are you trying to solve?

– Hueco
2 days ago














s it possible to quantify the sun in lumens? I think the only thing I've seen is that you can quantify in luxes. This question is no joke, excuse my ignorance, I am a little new in this. The problem I am trying to solve is to relate artificial light sources and natural light sources and see if there is any similarity between them, the only similarity I could find was through the color temperature.

– SRG
2 days ago





s it possible to quantify the sun in lumens? I think the only thing I've seen is that you can quantify in luxes. This question is no joke, excuse my ignorance, I am a little new in this. The problem I am trying to solve is to relate artificial light sources and natural light sources and see if there is any similarity between them, the only similarity I could find was through the color temperature.

– SRG
2 days ago













An example of relating to sources of natural and artificial light that I could think was sunrise and sunset and some household lamps. The sunlight at sunrise and sunset have a temperature of 2400 ° K while some light bulbs have a temperature of 2800 ° K, these are values ​​that are a little close, I thought about relating. Is this correct?

– SRG
2 days ago





An example of relating to sources of natural and artificial light that I could think was sunrise and sunset and some household lamps. The sunlight at sunrise and sunset have a temperature of 2400 ° K while some light bulbs have a temperature of 2800 ° K, these are values ​​that are a little close, I thought about relating. Is this correct?

– SRG
2 days ago










3 Answers
3






active

oldest

votes


















8














It's roughly true that light sources with the same color temperature have the same appearance. In fact, matching light sources in this way is exactly the reason we use the Kelvin WB scale in photography. However, there are three big caveats.



First, there's also a magenta-green axis



Human perception of color is complicated. White balance as measured in Kelvin is simplification of one aspect of that perception, basically relating to orange/blue balance. This is reasonably helpful for light sources that approximate blackbody radiation, but doesn't fit for a lot of artificial light sources, which may tilt more towards green or magenta — tints which are off the Kelvin WB scale. See How does Kelvin for color temperature relate to Kelvin for actual temperature? for details on the Kelvin scale, and Relationship between tint-temp and magenta-green-blue-amber white balance corrections?



Second, not every light source covers a complete spectrum



Sunlight filtered through the atmosphere, or the candlelight you mention, or an incandescent bulb — all of these have a clear weight on that Kelvin scale, but they also put out light across the visible spectrum (and into the invisible infrared and ultraviolet). This is not the case with gas-discharge or fluorescent light sources. That includes sodium-vapor streetlights, fluorescent bulbs, and LED lighting.



Our perception of color depends on wavelengths reflected by the lit objects in the scene. If those wavelengths are reduced (or entirely missing) in the source light, they can't be reflected, and that alters our perception of color.



For more on this, see
What is Colour Rendering Index (CRI)? — and Can I color-balance a photo if I know the light source within the photo?, where someone wants to balance color but is limited by the narrow-band light source.



Third, the numbers are nominal.



No candle flame snaps to exactly 1800K, and the color of sunrise and sunset is so complex that it's probably safe to say that literally every one is different. The labeled values on lights are not precise — probably more so for gear designed for photography, but consumer light bulbs will vary quite a bit from what the box says (as well as from brand to brand).



Sooooo.....



You ask:




Could you say that the values of the pixels are the same with these three sources of light?




And in practice, no, this is completely unlikely.



They may, however, be similar enough that they work together in a single photograph without causing the disruptive look we get when one area of the photograph is cool blue and another quite orange due to mixed lighting.



In your example of a bulb rated 2800K and a sunrise or sunset coming through a window (nominally 2400K), the window light may look a little warm (that is, warm in the artistic rather than physical sense: more orange) in your photograph balanced for the 2800K bulb — but then, that may be exactly what you want.






share|improve this answer

























  • Your answer seems excellent, but two more questions (sorry if I did not understand correctly), if I do not take into account the three warnings that you mention, would it be correct to relate somehow light bulb of 2800 ° k with the sunrise and sunset of 2400 ° k because their values ​​are "close"? Do you know any way in which you could relate the artificial light sources and the source of natural light (sun) in different conditions such as midday, sunrise, etc, that is, if there is any equivalence between them?

    – SRG
    2 days ago











  • Yes, they relate. That's exactly why we use this scale. If you have a flash rated for a daylight-like 5500K¸ it's roughly balanced with sunlight outdoors. If you have a flash balanced for 2800K, you can mix and match it with the light bulb you mention, without noticeable color shifts from the different light sources.

    – mattdm
    2 days ago











  • Thanks for your answers. Finally, you could give me references about your answers. I need to give references to justify my work. Maybe some book or some research article.

    – SRG
    2 days ago











  • I can... but I'm a little confused by the request. Is this homework? I'm happy to help you understand, but I'm not interested in doing your homework for you.

    – mattdm
    2 days ago











  • Okay, thank you very much.

    – SRG
    2 days ago


















1














Color temperature models a color spectrum only for blackbody radiation. This is pretty much perfect for plasma balls like the sun as seen from space. It also works to some degree for daylight (which is composed of a blue sky in the form of scattered sunlight and a yellowish tinted sun, together approximating the original sunlight). However, at dawn and sunset, there is a whole lot more of scattering and absorption going on. This doesn't change the temperature of the original light source but heavily modifies its spectrum. The result is not comparable to blackbody radiation even though it is a mostly continuous spectrum.



In contrast, a candle flame is more or less "the real thing" with regard to corresponding to blackbody radiation.



How much does this difference matter with regard to colors? Well, you rarely photograph direct light sources (like sun or candle flame) as primary objects, instead you are interested in the reflection of their light from colored surfaces. A non-white surface does not reflect light in the three primary colors RGB but rather in a continuum of the light spectrum (fluorescent colors are worse since they may respond with light of a different wavelength from what they are hit with, but let's not look at them for now). Thus even if, for the sake of argument, you manage to get matching colors from imaging a candle flame and a sunset, that doesn't mean that the scene lit by them exhibits the same color.



This is sort of the bane of paint manufacturers: they cannot afford to match paints using an RGB (or other merely three-dimensional) model since that only works assuming one particular light source wavelength distribution. At the worst, paints match perfectly in daylight and diverge already when it gets overcast. Making paints of different composition match even under a variety of flourescent lightings is a nightmare.






share|improve this answer






























    0














    It wouldn't be accurate to say the sources are the same but it would be accurate to say the they are similar. Atmospheric differences (moisture, dust, etc.) can change the color temperature of the sun not just from day to day, but even from minute to minute.



    Since lighting conditions are often dim, if you want to photograph a subject in these conditions, a flash might be used. You can use a CTO gel on the flash (CTO = Color Temperature Orange) to bring the color of the flash closer to the color of the candlelight or sunlight so that any color-adjustments performed in post processing wont have radically different color temperatures. But even the CTO gels come in 1/4, 1/2, 3/4 and full CTO strength (depending on whether you need a pale yellow/gold vs. an intense orange).






    share|improve this answer























    • If it was not too much trouble, could you give me references about your answer. I need to give references to justify my work. Maybe some book or some research article.

      – SRG
      2 days ago











    Your Answer








    StackExchange.ready(function()
    var channelOptions =
    tags: "".split(" "),
    id: "61"
    ;
    initTagRenderer("".split(" "), "".split(" "), channelOptions);

    StackExchange.using("externalEditor", function()
    // Have to fire editor after snippets, if snippets enabled
    if (StackExchange.settings.snippets.snippetsEnabled)
    StackExchange.using("snippets", function()
    createEditor();
    );

    else
    createEditor();

    );

    function createEditor()
    StackExchange.prepareEditor(
    heartbeatType: 'answer',
    autoActivateHeartbeat: false,
    convertImagesToLinks: false,
    noModals: true,
    showLowRepImageUploadWarning: true,
    reputationToPostImages: null,
    bindNavPrevention: true,
    postfix: "",
    imageUploader:
    brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
    contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
    allowUrls: true
    ,
    noCode: true, onDemand: true,
    discardSelector: ".discard-answer"
    ,immediatelyShowMarkdownHelp:true
    );



    );






    SRG is a new contributor. Be nice, and check out our Code of Conduct.









    draft saved

    draft discarded


















    StackExchange.ready(
    function ()
    StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fphoto.stackexchange.com%2fquestions%2f106302%2fit-is-correct-to-match-light-sources-with-the-same-color-temperature%23new-answer', 'question_page');

    );

    Post as a guest















    Required, but never shown

























    3 Answers
    3






    active

    oldest

    votes








    3 Answers
    3






    active

    oldest

    votes









    active

    oldest

    votes






    active

    oldest

    votes









    8














    It's roughly true that light sources with the same color temperature have the same appearance. In fact, matching light sources in this way is exactly the reason we use the Kelvin WB scale in photography. However, there are three big caveats.



    First, there's also a magenta-green axis



    Human perception of color is complicated. White balance as measured in Kelvin is simplification of one aspect of that perception, basically relating to orange/blue balance. This is reasonably helpful for light sources that approximate blackbody radiation, but doesn't fit for a lot of artificial light sources, which may tilt more towards green or magenta — tints which are off the Kelvin WB scale. See How does Kelvin for color temperature relate to Kelvin for actual temperature? for details on the Kelvin scale, and Relationship between tint-temp and magenta-green-blue-amber white balance corrections?



    Second, not every light source covers a complete spectrum



    Sunlight filtered through the atmosphere, or the candlelight you mention, or an incandescent bulb — all of these have a clear weight on that Kelvin scale, but they also put out light across the visible spectrum (and into the invisible infrared and ultraviolet). This is not the case with gas-discharge or fluorescent light sources. That includes sodium-vapor streetlights, fluorescent bulbs, and LED lighting.



    Our perception of color depends on wavelengths reflected by the lit objects in the scene. If those wavelengths are reduced (or entirely missing) in the source light, they can't be reflected, and that alters our perception of color.



    For more on this, see
    What is Colour Rendering Index (CRI)? — and Can I color-balance a photo if I know the light source within the photo?, where someone wants to balance color but is limited by the narrow-band light source.



    Third, the numbers are nominal.



    No candle flame snaps to exactly 1800K, and the color of sunrise and sunset is so complex that it's probably safe to say that literally every one is different. The labeled values on lights are not precise — probably more so for gear designed for photography, but consumer light bulbs will vary quite a bit from what the box says (as well as from brand to brand).



    Sooooo.....



    You ask:




    Could you say that the values of the pixels are the same with these three sources of light?




    And in practice, no, this is completely unlikely.



    They may, however, be similar enough that they work together in a single photograph without causing the disruptive look we get when one area of the photograph is cool blue and another quite orange due to mixed lighting.



    In your example of a bulb rated 2800K and a sunrise or sunset coming through a window (nominally 2400K), the window light may look a little warm (that is, warm in the artistic rather than physical sense: more orange) in your photograph balanced for the 2800K bulb — but then, that may be exactly what you want.






    share|improve this answer

























    • Your answer seems excellent, but two more questions (sorry if I did not understand correctly), if I do not take into account the three warnings that you mention, would it be correct to relate somehow light bulb of 2800 ° k with the sunrise and sunset of 2400 ° k because their values ​​are "close"? Do you know any way in which you could relate the artificial light sources and the source of natural light (sun) in different conditions such as midday, sunrise, etc, that is, if there is any equivalence between them?

      – SRG
      2 days ago











    • Yes, they relate. That's exactly why we use this scale. If you have a flash rated for a daylight-like 5500K¸ it's roughly balanced with sunlight outdoors. If you have a flash balanced for 2800K, you can mix and match it with the light bulb you mention, without noticeable color shifts from the different light sources.

      – mattdm
      2 days ago











    • Thanks for your answers. Finally, you could give me references about your answers. I need to give references to justify my work. Maybe some book or some research article.

      – SRG
      2 days ago











    • I can... but I'm a little confused by the request. Is this homework? I'm happy to help you understand, but I'm not interested in doing your homework for you.

      – mattdm
      2 days ago











    • Okay, thank you very much.

      – SRG
      2 days ago















    8














    It's roughly true that light sources with the same color temperature have the same appearance. In fact, matching light sources in this way is exactly the reason we use the Kelvin WB scale in photography. However, there are three big caveats.



    First, there's also a magenta-green axis



    Human perception of color is complicated. White balance as measured in Kelvin is simplification of one aspect of that perception, basically relating to orange/blue balance. This is reasonably helpful for light sources that approximate blackbody radiation, but doesn't fit for a lot of artificial light sources, which may tilt more towards green or magenta — tints which are off the Kelvin WB scale. See How does Kelvin for color temperature relate to Kelvin for actual temperature? for details on the Kelvin scale, and Relationship between tint-temp and magenta-green-blue-amber white balance corrections?



    Second, not every light source covers a complete spectrum



    Sunlight filtered through the atmosphere, or the candlelight you mention, or an incandescent bulb — all of these have a clear weight on that Kelvin scale, but they also put out light across the visible spectrum (and into the invisible infrared and ultraviolet). This is not the case with gas-discharge or fluorescent light sources. That includes sodium-vapor streetlights, fluorescent bulbs, and LED lighting.



    Our perception of color depends on wavelengths reflected by the lit objects in the scene. If those wavelengths are reduced (or entirely missing) in the source light, they can't be reflected, and that alters our perception of color.



    For more on this, see
    What is Colour Rendering Index (CRI)? — and Can I color-balance a photo if I know the light source within the photo?, where someone wants to balance color but is limited by the narrow-band light source.



    Third, the numbers are nominal.



    No candle flame snaps to exactly 1800K, and the color of sunrise and sunset is so complex that it's probably safe to say that literally every one is different. The labeled values on lights are not precise — probably more so for gear designed for photography, but consumer light bulbs will vary quite a bit from what the box says (as well as from brand to brand).



    Sooooo.....



    You ask:




    Could you say that the values of the pixels are the same with these three sources of light?




    And in practice, no, this is completely unlikely.



    They may, however, be similar enough that they work together in a single photograph without causing the disruptive look we get when one area of the photograph is cool blue and another quite orange due to mixed lighting.



    In your example of a bulb rated 2800K and a sunrise or sunset coming through a window (nominally 2400K), the window light may look a little warm (that is, warm in the artistic rather than physical sense: more orange) in your photograph balanced for the 2800K bulb — but then, that may be exactly what you want.






    share|improve this answer

























    • Your answer seems excellent, but two more questions (sorry if I did not understand correctly), if I do not take into account the three warnings that you mention, would it be correct to relate somehow light bulb of 2800 ° k with the sunrise and sunset of 2400 ° k because their values ​​are "close"? Do you know any way in which you could relate the artificial light sources and the source of natural light (sun) in different conditions such as midday, sunrise, etc, that is, if there is any equivalence between them?

      – SRG
      2 days ago











    • Yes, they relate. That's exactly why we use this scale. If you have a flash rated for a daylight-like 5500K¸ it's roughly balanced with sunlight outdoors. If you have a flash balanced for 2800K, you can mix and match it with the light bulb you mention, without noticeable color shifts from the different light sources.

      – mattdm
      2 days ago











    • Thanks for your answers. Finally, you could give me references about your answers. I need to give references to justify my work. Maybe some book or some research article.

      – SRG
      2 days ago











    • I can... but I'm a little confused by the request. Is this homework? I'm happy to help you understand, but I'm not interested in doing your homework for you.

      – mattdm
      2 days ago











    • Okay, thank you very much.

      – SRG
      2 days ago













    8












    8








    8







    It's roughly true that light sources with the same color temperature have the same appearance. In fact, matching light sources in this way is exactly the reason we use the Kelvin WB scale in photography. However, there are three big caveats.



    First, there's also a magenta-green axis



    Human perception of color is complicated. White balance as measured in Kelvin is simplification of one aspect of that perception, basically relating to orange/blue balance. This is reasonably helpful for light sources that approximate blackbody radiation, but doesn't fit for a lot of artificial light sources, which may tilt more towards green or magenta — tints which are off the Kelvin WB scale. See How does Kelvin for color temperature relate to Kelvin for actual temperature? for details on the Kelvin scale, and Relationship between tint-temp and magenta-green-blue-amber white balance corrections?



    Second, not every light source covers a complete spectrum



    Sunlight filtered through the atmosphere, or the candlelight you mention, or an incandescent bulb — all of these have a clear weight on that Kelvin scale, but they also put out light across the visible spectrum (and into the invisible infrared and ultraviolet). This is not the case with gas-discharge or fluorescent light sources. That includes sodium-vapor streetlights, fluorescent bulbs, and LED lighting.



    Our perception of color depends on wavelengths reflected by the lit objects in the scene. If those wavelengths are reduced (or entirely missing) in the source light, they can't be reflected, and that alters our perception of color.



    For more on this, see
    What is Colour Rendering Index (CRI)? — and Can I color-balance a photo if I know the light source within the photo?, where someone wants to balance color but is limited by the narrow-band light source.



    Third, the numbers are nominal.



    No candle flame snaps to exactly 1800K, and the color of sunrise and sunset is so complex that it's probably safe to say that literally every one is different. The labeled values on lights are not precise — probably more so for gear designed for photography, but consumer light bulbs will vary quite a bit from what the box says (as well as from brand to brand).



    Sooooo.....



    You ask:




    Could you say that the values of the pixels are the same with these three sources of light?




    And in practice, no, this is completely unlikely.



    They may, however, be similar enough that they work together in a single photograph without causing the disruptive look we get when one area of the photograph is cool blue and another quite orange due to mixed lighting.



    In your example of a bulb rated 2800K and a sunrise or sunset coming through a window (nominally 2400K), the window light may look a little warm (that is, warm in the artistic rather than physical sense: more orange) in your photograph balanced for the 2800K bulb — but then, that may be exactly what you want.






    share|improve this answer















    It's roughly true that light sources with the same color temperature have the same appearance. In fact, matching light sources in this way is exactly the reason we use the Kelvin WB scale in photography. However, there are three big caveats.



    First, there's also a magenta-green axis



    Human perception of color is complicated. White balance as measured in Kelvin is simplification of one aspect of that perception, basically relating to orange/blue balance. This is reasonably helpful for light sources that approximate blackbody radiation, but doesn't fit for a lot of artificial light sources, which may tilt more towards green or magenta — tints which are off the Kelvin WB scale. See How does Kelvin for color temperature relate to Kelvin for actual temperature? for details on the Kelvin scale, and Relationship between tint-temp and magenta-green-blue-amber white balance corrections?



    Second, not every light source covers a complete spectrum



    Sunlight filtered through the atmosphere, or the candlelight you mention, or an incandescent bulb — all of these have a clear weight on that Kelvin scale, but they also put out light across the visible spectrum (and into the invisible infrared and ultraviolet). This is not the case with gas-discharge or fluorescent light sources. That includes sodium-vapor streetlights, fluorescent bulbs, and LED lighting.



    Our perception of color depends on wavelengths reflected by the lit objects in the scene. If those wavelengths are reduced (or entirely missing) in the source light, they can't be reflected, and that alters our perception of color.



    For more on this, see
    What is Colour Rendering Index (CRI)? — and Can I color-balance a photo if I know the light source within the photo?, where someone wants to balance color but is limited by the narrow-band light source.



    Third, the numbers are nominal.



    No candle flame snaps to exactly 1800K, and the color of sunrise and sunset is so complex that it's probably safe to say that literally every one is different. The labeled values on lights are not precise — probably more so for gear designed for photography, but consumer light bulbs will vary quite a bit from what the box says (as well as from brand to brand).



    Sooooo.....



    You ask:




    Could you say that the values of the pixels are the same with these three sources of light?




    And in practice, no, this is completely unlikely.



    They may, however, be similar enough that they work together in a single photograph without causing the disruptive look we get when one area of the photograph is cool blue and another quite orange due to mixed lighting.



    In your example of a bulb rated 2800K and a sunrise or sunset coming through a window (nominally 2400K), the window light may look a little warm (that is, warm in the artistic rather than physical sense: more orange) in your photograph balanced for the 2800K bulb — but then, that may be exactly what you want.







    share|improve this answer














    share|improve this answer



    share|improve this answer








    edited 2 days ago

























    answered 2 days ago









    mattdmmattdm

    122k40357653




    122k40357653












    • Your answer seems excellent, but two more questions (sorry if I did not understand correctly), if I do not take into account the three warnings that you mention, would it be correct to relate somehow light bulb of 2800 ° k with the sunrise and sunset of 2400 ° k because their values ​​are "close"? Do you know any way in which you could relate the artificial light sources and the source of natural light (sun) in different conditions such as midday, sunrise, etc, that is, if there is any equivalence between them?

      – SRG
      2 days ago











    • Yes, they relate. That's exactly why we use this scale. If you have a flash rated for a daylight-like 5500K¸ it's roughly balanced with sunlight outdoors. If you have a flash balanced for 2800K, you can mix and match it with the light bulb you mention, without noticeable color shifts from the different light sources.

      – mattdm
      2 days ago











    • Thanks for your answers. Finally, you could give me references about your answers. I need to give references to justify my work. Maybe some book or some research article.

      – SRG
      2 days ago











    • I can... but I'm a little confused by the request. Is this homework? I'm happy to help you understand, but I'm not interested in doing your homework for you.

      – mattdm
      2 days ago











    • Okay, thank you very much.

      – SRG
      2 days ago

















    • Your answer seems excellent, but two more questions (sorry if I did not understand correctly), if I do not take into account the three warnings that you mention, would it be correct to relate somehow light bulb of 2800 ° k with the sunrise and sunset of 2400 ° k because their values ​​are "close"? Do you know any way in which you could relate the artificial light sources and the source of natural light (sun) in different conditions such as midday, sunrise, etc, that is, if there is any equivalence between them?

      – SRG
      2 days ago











    • Yes, they relate. That's exactly why we use this scale. If you have a flash rated for a daylight-like 5500K¸ it's roughly balanced with sunlight outdoors. If you have a flash balanced for 2800K, you can mix and match it with the light bulb you mention, without noticeable color shifts from the different light sources.

      – mattdm
      2 days ago











    • Thanks for your answers. Finally, you could give me references about your answers. I need to give references to justify my work. Maybe some book or some research article.

      – SRG
      2 days ago











    • I can... but I'm a little confused by the request. Is this homework? I'm happy to help you understand, but I'm not interested in doing your homework for you.

      – mattdm
      2 days ago











    • Okay, thank you very much.

      – SRG
      2 days ago
















    Your answer seems excellent, but two more questions (sorry if I did not understand correctly), if I do not take into account the three warnings that you mention, would it be correct to relate somehow light bulb of 2800 ° k with the sunrise and sunset of 2400 ° k because their values ​​are "close"? Do you know any way in which you could relate the artificial light sources and the source of natural light (sun) in different conditions such as midday, sunrise, etc, that is, if there is any equivalence between them?

    – SRG
    2 days ago





    Your answer seems excellent, but two more questions (sorry if I did not understand correctly), if I do not take into account the three warnings that you mention, would it be correct to relate somehow light bulb of 2800 ° k with the sunrise and sunset of 2400 ° k because their values ​​are "close"? Do you know any way in which you could relate the artificial light sources and the source of natural light (sun) in different conditions such as midday, sunrise, etc, that is, if there is any equivalence between them?

    – SRG
    2 days ago













    Yes, they relate. That's exactly why we use this scale. If you have a flash rated for a daylight-like 5500K¸ it's roughly balanced with sunlight outdoors. If you have a flash balanced for 2800K, you can mix and match it with the light bulb you mention, without noticeable color shifts from the different light sources.

    – mattdm
    2 days ago





    Yes, they relate. That's exactly why we use this scale. If you have a flash rated for a daylight-like 5500K¸ it's roughly balanced with sunlight outdoors. If you have a flash balanced for 2800K, you can mix and match it with the light bulb you mention, without noticeable color shifts from the different light sources.

    – mattdm
    2 days ago













    Thanks for your answers. Finally, you could give me references about your answers. I need to give references to justify my work. Maybe some book or some research article.

    – SRG
    2 days ago





    Thanks for your answers. Finally, you could give me references about your answers. I need to give references to justify my work. Maybe some book or some research article.

    – SRG
    2 days ago













    I can... but I'm a little confused by the request. Is this homework? I'm happy to help you understand, but I'm not interested in doing your homework for you.

    – mattdm
    2 days ago





    I can... but I'm a little confused by the request. Is this homework? I'm happy to help you understand, but I'm not interested in doing your homework for you.

    – mattdm
    2 days ago













    Okay, thank you very much.

    – SRG
    2 days ago





    Okay, thank you very much.

    – SRG
    2 days ago













    1














    Color temperature models a color spectrum only for blackbody radiation. This is pretty much perfect for plasma balls like the sun as seen from space. It also works to some degree for daylight (which is composed of a blue sky in the form of scattered sunlight and a yellowish tinted sun, together approximating the original sunlight). However, at dawn and sunset, there is a whole lot more of scattering and absorption going on. This doesn't change the temperature of the original light source but heavily modifies its spectrum. The result is not comparable to blackbody radiation even though it is a mostly continuous spectrum.



    In contrast, a candle flame is more or less "the real thing" with regard to corresponding to blackbody radiation.



    How much does this difference matter with regard to colors? Well, you rarely photograph direct light sources (like sun or candle flame) as primary objects, instead you are interested in the reflection of their light from colored surfaces. A non-white surface does not reflect light in the three primary colors RGB but rather in a continuum of the light spectrum (fluorescent colors are worse since they may respond with light of a different wavelength from what they are hit with, but let's not look at them for now). Thus even if, for the sake of argument, you manage to get matching colors from imaging a candle flame and a sunset, that doesn't mean that the scene lit by them exhibits the same color.



    This is sort of the bane of paint manufacturers: they cannot afford to match paints using an RGB (or other merely three-dimensional) model since that only works assuming one particular light source wavelength distribution. At the worst, paints match perfectly in daylight and diverge already when it gets overcast. Making paints of different composition match even under a variety of flourescent lightings is a nightmare.






    share|improve this answer



























      1














      Color temperature models a color spectrum only for blackbody radiation. This is pretty much perfect for plasma balls like the sun as seen from space. It also works to some degree for daylight (which is composed of a blue sky in the form of scattered sunlight and a yellowish tinted sun, together approximating the original sunlight). However, at dawn and sunset, there is a whole lot more of scattering and absorption going on. This doesn't change the temperature of the original light source but heavily modifies its spectrum. The result is not comparable to blackbody radiation even though it is a mostly continuous spectrum.



      In contrast, a candle flame is more or less "the real thing" with regard to corresponding to blackbody radiation.



      How much does this difference matter with regard to colors? Well, you rarely photograph direct light sources (like sun or candle flame) as primary objects, instead you are interested in the reflection of their light from colored surfaces. A non-white surface does not reflect light in the three primary colors RGB but rather in a continuum of the light spectrum (fluorescent colors are worse since they may respond with light of a different wavelength from what they are hit with, but let's not look at them for now). Thus even if, for the sake of argument, you manage to get matching colors from imaging a candle flame and a sunset, that doesn't mean that the scene lit by them exhibits the same color.



      This is sort of the bane of paint manufacturers: they cannot afford to match paints using an RGB (or other merely three-dimensional) model since that only works assuming one particular light source wavelength distribution. At the worst, paints match perfectly in daylight and diverge already when it gets overcast. Making paints of different composition match even under a variety of flourescent lightings is a nightmare.






      share|improve this answer

























        1












        1








        1







        Color temperature models a color spectrum only for blackbody radiation. This is pretty much perfect for plasma balls like the sun as seen from space. It also works to some degree for daylight (which is composed of a blue sky in the form of scattered sunlight and a yellowish tinted sun, together approximating the original sunlight). However, at dawn and sunset, there is a whole lot more of scattering and absorption going on. This doesn't change the temperature of the original light source but heavily modifies its spectrum. The result is not comparable to blackbody radiation even though it is a mostly continuous spectrum.



        In contrast, a candle flame is more or less "the real thing" with regard to corresponding to blackbody radiation.



        How much does this difference matter with regard to colors? Well, you rarely photograph direct light sources (like sun or candle flame) as primary objects, instead you are interested in the reflection of their light from colored surfaces. A non-white surface does not reflect light in the three primary colors RGB but rather in a continuum of the light spectrum (fluorescent colors are worse since they may respond with light of a different wavelength from what they are hit with, but let's not look at them for now). Thus even if, for the sake of argument, you manage to get matching colors from imaging a candle flame and a sunset, that doesn't mean that the scene lit by them exhibits the same color.



        This is sort of the bane of paint manufacturers: they cannot afford to match paints using an RGB (or other merely three-dimensional) model since that only works assuming one particular light source wavelength distribution. At the worst, paints match perfectly in daylight and diverge already when it gets overcast. Making paints of different composition match even under a variety of flourescent lightings is a nightmare.






        share|improve this answer













        Color temperature models a color spectrum only for blackbody radiation. This is pretty much perfect for plasma balls like the sun as seen from space. It also works to some degree for daylight (which is composed of a blue sky in the form of scattered sunlight and a yellowish tinted sun, together approximating the original sunlight). However, at dawn and sunset, there is a whole lot more of scattering and absorption going on. This doesn't change the temperature of the original light source but heavily modifies its spectrum. The result is not comparable to blackbody radiation even though it is a mostly continuous spectrum.



        In contrast, a candle flame is more or less "the real thing" with regard to corresponding to blackbody radiation.



        How much does this difference matter with regard to colors? Well, you rarely photograph direct light sources (like sun or candle flame) as primary objects, instead you are interested in the reflection of their light from colored surfaces. A non-white surface does not reflect light in the three primary colors RGB but rather in a continuum of the light spectrum (fluorescent colors are worse since they may respond with light of a different wavelength from what they are hit with, but let's not look at them for now). Thus even if, for the sake of argument, you manage to get matching colors from imaging a candle flame and a sunset, that doesn't mean that the scene lit by them exhibits the same color.



        This is sort of the bane of paint manufacturers: they cannot afford to match paints using an RGB (or other merely three-dimensional) model since that only works assuming one particular light source wavelength distribution. At the worst, paints match perfectly in daylight and diverge already when it gets overcast. Making paints of different composition match even under a variety of flourescent lightings is a nightmare.







        share|improve this answer












        share|improve this answer



        share|improve this answer










        answered 2 days ago







        user82975




























            0














            It wouldn't be accurate to say the sources are the same but it would be accurate to say the they are similar. Atmospheric differences (moisture, dust, etc.) can change the color temperature of the sun not just from day to day, but even from minute to minute.



            Since lighting conditions are often dim, if you want to photograph a subject in these conditions, a flash might be used. You can use a CTO gel on the flash (CTO = Color Temperature Orange) to bring the color of the flash closer to the color of the candlelight or sunlight so that any color-adjustments performed in post processing wont have radically different color temperatures. But even the CTO gels come in 1/4, 1/2, 3/4 and full CTO strength (depending on whether you need a pale yellow/gold vs. an intense orange).






            share|improve this answer























            • If it was not too much trouble, could you give me references about your answer. I need to give references to justify my work. Maybe some book or some research article.

              – SRG
              2 days ago















            0














            It wouldn't be accurate to say the sources are the same but it would be accurate to say the they are similar. Atmospheric differences (moisture, dust, etc.) can change the color temperature of the sun not just from day to day, but even from minute to minute.



            Since lighting conditions are often dim, if you want to photograph a subject in these conditions, a flash might be used. You can use a CTO gel on the flash (CTO = Color Temperature Orange) to bring the color of the flash closer to the color of the candlelight or sunlight so that any color-adjustments performed in post processing wont have radically different color temperatures. But even the CTO gels come in 1/4, 1/2, 3/4 and full CTO strength (depending on whether you need a pale yellow/gold vs. an intense orange).






            share|improve this answer























            • If it was not too much trouble, could you give me references about your answer. I need to give references to justify my work. Maybe some book or some research article.

              – SRG
              2 days ago













            0












            0








            0







            It wouldn't be accurate to say the sources are the same but it would be accurate to say the they are similar. Atmospheric differences (moisture, dust, etc.) can change the color temperature of the sun not just from day to day, but even from minute to minute.



            Since lighting conditions are often dim, if you want to photograph a subject in these conditions, a flash might be used. You can use a CTO gel on the flash (CTO = Color Temperature Orange) to bring the color of the flash closer to the color of the candlelight or sunlight so that any color-adjustments performed in post processing wont have radically different color temperatures. But even the CTO gels come in 1/4, 1/2, 3/4 and full CTO strength (depending on whether you need a pale yellow/gold vs. an intense orange).






            share|improve this answer













            It wouldn't be accurate to say the sources are the same but it would be accurate to say the they are similar. Atmospheric differences (moisture, dust, etc.) can change the color temperature of the sun not just from day to day, but even from minute to minute.



            Since lighting conditions are often dim, if you want to photograph a subject in these conditions, a flash might be used. You can use a CTO gel on the flash (CTO = Color Temperature Orange) to bring the color of the flash closer to the color of the candlelight or sunlight so that any color-adjustments performed in post processing wont have radically different color temperatures. But even the CTO gels come in 1/4, 1/2, 3/4 and full CTO strength (depending on whether you need a pale yellow/gold vs. an intense orange).







            share|improve this answer












            share|improve this answer



            share|improve this answer










            answered 2 days ago









            Tim CampbellTim Campbell

            5266




            5266












            • If it was not too much trouble, could you give me references about your answer. I need to give references to justify my work. Maybe some book or some research article.

              – SRG
              2 days ago

















            • If it was not too much trouble, could you give me references about your answer. I need to give references to justify my work. Maybe some book or some research article.

              – SRG
              2 days ago
















            If it was not too much trouble, could you give me references about your answer. I need to give references to justify my work. Maybe some book or some research article.

            – SRG
            2 days ago





            If it was not too much trouble, could you give me references about your answer. I need to give references to justify my work. Maybe some book or some research article.

            – SRG
            2 days ago










            SRG is a new contributor. Be nice, and check out our Code of Conduct.









            draft saved

            draft discarded


















            SRG is a new contributor. Be nice, and check out our Code of Conduct.












            SRG is a new contributor. Be nice, and check out our Code of Conduct.











            SRG is a new contributor. Be nice, and check out our Code of Conduct.














            Thanks for contributing an answer to Photography Stack Exchange!


            • Please be sure to answer the question. Provide details and share your research!

            But avoid


            • Asking for help, clarification, or responding to other answers.

            • Making statements based on opinion; back them up with references or personal experience.

            To learn more, see our tips on writing great answers.




            draft saved


            draft discarded














            StackExchange.ready(
            function ()
            StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fphoto.stackexchange.com%2fquestions%2f106302%2fit-is-correct-to-match-light-sources-with-the-same-color-temperature%23new-answer', 'question_page');

            );

            Post as a guest















            Required, but never shown





















































            Required, but never shown














            Required, but never shown












            Required, but never shown







            Required, but never shown

































            Required, but never shown














            Required, but never shown












            Required, but never shown







            Required, but never shown







            Popular posts from this blog

            Romeo and Juliet ContentsCharactersSynopsisSourcesDate and textThemes and motifsCriticism and interpretationLegacyScene by sceneSee alsoNotes and referencesSourcesExternal linksNavigation menu"Consumer Price Index (estimate) 1800–"10.2307/28710160037-3222287101610.1093/res/II.5.31910.2307/45967845967810.2307/2869925286992510.1525/jams.1982.35.3.03a00050"Dada Masilo: South African dancer who breaks the rules"10.1093/res/os-XV.57.1610.2307/28680942868094"Sweet Sorrow: Mann-Korman's Romeo and Juliet Closes Sept. 5 at MN's Ordway"the original10.2307/45957745957710.1017/CCOL0521570476.009"Ram Leela box office collections hit massive Rs 100 crore, pulverises prediction"Archived"Broadway Revival of Romeo and Juliet, Starring Orlando Bloom and Condola Rashad, Will Close Dec. 8"Archived10.1075/jhp.7.1.04hon"Wherefore art thou, Romeo? To make us laugh at Navy Pier"the original10.1093/gmo/9781561592630.article.O006772"Ram-leela Review Roundup: Critics Hail Film as Best Adaptation of Romeo and Juliet"Archived10.2307/31946310047-77293194631"Romeo and Juliet get Twitter treatment""Juliet's Nurse by Lois Leveen""Romeo and Juliet: Orlando Bloom's Broadway Debut Released in Theaters for Valentine's Day"Archived"Romeo and Juliet Has No Balcony"10.1093/gmo/9781561592630.article.O00778110.2307/2867423286742310.1076/enst.82.2.115.959510.1080/00138380601042675"A plague o' both your houses: error in GCSE exam paper forces apology""Juliet of the Five O'Clock Shadow, and Other Wonders"10.2307/33912430027-4321339124310.2307/28487440038-7134284874410.2307/29123140149-661129123144728341M"Weekender Guide: Shakespeare on The Drive""balcony"UK public library membership"romeo"UK public library membership10.1017/CCOL9780521844291"Post-Zionist Critique on Israel and the Palestinians Part III: Popular Culture"10.2307/25379071533-86140377-919X2537907"Capulets and Montagues: UK exam board admit mixing names up in Romeo and Juliet paper"Istoria Novellamente Ritrovata di Due Nobili Amanti2027/mdp.390150822329610820-750X"GCSE exam error: Board accidentally rewrites Shakespeare"10.2307/29176390149-66112917639"Exam board apologises after error in English GCSE paper which confused characters in Shakespeare's Romeo and Juliet""From Mariotto and Ganozza to Romeo and Guilietta: Metamorphoses of a Renaissance Tale"10.2307/37323537323510.2307/2867455286745510.2307/28678912867891"10 Questions for Taylor Swift"10.2307/28680922868092"Haymarket Theatre""The Zeffirelli Way: Revealing Talk by Florentine Director""Michael Smuin: 1938-2007 / Prolific dance director had showy career"The Life and Art of Edwin BoothRomeo and JulietRomeo and JulietRomeo and JulietRomeo and JulietEasy Read Romeo and JulietRomeo and Julieteeecb12003684p(data)4099369-3n8211610759dbe00d-a9e2-41a3-b2c1-977dd692899302814385X313670221313670221

            Creating closest line along the point''s azimuth using PostgreSQL Planned maintenance scheduled April 17/18, 2019 at 00:00UTC (8:00pm US/Eastern) Announcing the arrival of Valued Associate #679: Cesar Manara Unicorn Meta Zoo #1: Why another podcast?Drawing line between points at specific distance in PostGIS?How to efficiently find the closest point over the dateline?How to find the nearest point by using PostGIS function?PostGIS nearest point with LATERAL JOIN in PostgreSQL 9.3+Creating a table and inserting selected streets using plpgsql functionsCreating a table that stores Distances and other columnSaving select query results (year wise) from PostgreSQL/PostGIS to text filesWhat is the information behind this geometry?How to give start and end vertex ids dynamically in pgr_dijkstra?Point to Polygon nearest distance DS_distance is not using geography index & knn <-> or <#> does not give result in orderLine to point conversion with start point and end point detection?

            Crop image to path created in TikZ? Announcing the arrival of Valued Associate #679: Cesar Manara Planned maintenance scheduled April 17/18, 2019 at 00:00UTC (8:00pm US/Eastern)Crop an inserted image?TikZ pictures does not appear in posterImage behind and beyond crop marks?Tikz picture as large as possible on A4 PageTransparency vs image compression dilemmaHow to crop background from image automatically?Image does not cropTikzexternal capturing crop marks when externalizing pgfplots?How to include image path that contains a dollar signCrop image with left size given