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Archive 1 |
Right now this article mainly discusses the practical application of color temperature in cinematography -- we need information on the physics of it...
Agreed. But I don't know anything about the physics of it. -- Koyaanis Qatsi
Nice work anyway KQ! I really enjoyed reading it (OK, it does need the techie stuff though) - MMGB
yeh. and the prose needs a little work. but i'm off to bed now. :-) thanks, though. much appreciated. -- Koyaanis Qatsi
Added more physics-oriented discussion, made distinction between colour temperature and white balance. -- The Anome
Hehe - Article title "Color Temperature". First sentence "Colour temperature...". God I love this place. - MMGB
Yeh, it's great. Thanks, Anome, for adding the physics stuff. Sorry to use the term "loosely"; it's very common in the film & documentary industry. -- Koyaanis Qatsi
Yep, I know -- The Anome
Cinematographers don't/can't "white balance" in the same way as video camera operators: they can use techniques such as filters, pre-flashing, and after shooting, color grading (both by exposure at the labs, and also digitally, where digital film processes are used). This needs to be incorporated into the article. -- Anon.
Yes, it does need to be integrated into it. I've worked with both film and video, and noticed that, but never noticed the lack of coverage in the article. However, I'm off to bed now, so I'm glad to see you've added it. Thanks. :-) Koyaanis Qatsi 07:20 17 Jun 2003 (UTC)
Mark Sweep created pure art work from your basic start. I tried to help a little too. I want color temp to link like this, but I'm gettng the wrong words incandescent or incandescance, should link to the section called Incandescent Bulbs but [ "Incandescent" / "Incandescent Bulbs" ]]doesn't give me back my original word.gimma quick lessson please.I want to do this to fluorescence too.[User:Dkroll2|Dkroll2]]--[[User:Dkroll2| Dkroll2]] 04:09, Dec 14, 2004 (UTC)
All you need to do is write this: [[Incandescent light bulb|incandescent]] he pipe character "|" is used to show different text in a wikilink. Put the article name before the pipe, and the desired text of the link after the pipe. It'll show up like this: incandescent. But please remember that we only need to link the first time each term is used. There's no need to go through articles linking every instance of the term "incandescent". Rhobite 05:17, Dec 14, 2004 (UTC)
OOPS!//excuse me whilst I go fix a ton of stuff. DKroll2 OK you Color Temp guys got your physics, well some of it. Enough so It it didn't get too complex. I didnt agree about white balance and photography, since there are so many alternative applications, but at least you HAVE applications sections. AND I learned a bit mre about how white balance relates to color temp. thanks DKroll2
The plot showing a spectral power distribution looks representative of older "halophosphate" fluorescents, but not of the majority of modern tubes found in offices etc which use a newer "triphosphor" mix. My personal web page has a measured triphosphor spectrum (don't use as a wikipedia source!) http://www.techmind.org/colour/tld32w84hfsml.gif the key point being that the modern triphosphors have a very spikey spectrum with very little continuum at all. You may find emission spectra graphics from Philips/GE-Lighting/...
For spikey emission spectra, even if the overall colour were equivalent to a blackbody, the way it renders reflective (object) colours will always be "off" [colour-rendering issues - reflected colour arise from the product of the lightsource spectral power distribution and the object spectral reflectance]. Consequently, for photography it can still be impossible to properly colour-correct fluorescent light using filters.
I'll try and explain myself better and edit the article itself sometime.
57.66.65.38 12:58, 23 August 2006 (UTC) Andrew Steer ( http://www.techmind.org )
Question about citations.
I did 2 with success on those sections I wrote, but:
1: how many sections/paragraphs up from the citation is it valid? problem: I desire to find citations for my contributions, but not to some others, with whom I disagree, etc.
How do I limit my citations to my writings?
A thought: What if my writings are eventually rewritten, or even just editing incorrectly? The citation is invalid and is an insult to the cited author.
Hmmmm.--[[User:Dkroll2| Dkroll2]] 06:23, Dec 23, 2004 (UTC)
I fixed the link to Planck's Law, but I wondered if that shouldn't be Planck's_law_of_black_body_radiation? -- Lemming 21:57, 21 Jun 2005 (UTC)
hmm I've been thinking (not expert, just a question :) ) how does colour temperature relate to cold/warm colours? I mean, red is a "warm colour", and blue is a "white colour" but according to colour temperature, it's the opposite. Is there anyone who sees the problem (and can clear things)?
Our ideas about hot, warm, cool, and cold temperatures are psycological associations based on the common experiences of man since time immemorial. Red is the color of many things hot: fire, embers, lava, molten steel, even sunburned skin. Something "red-hot" is considered very, very hot. Orange and yellow, other "warm" colors, are also often seen in fire. Blue, on the other hand, is associated with water and ice. It's considered very cold. Green is associated with things like leaves and grass. These things are usually somewhat cool to the touch (they conduct heat away from your skin), but not cold like water and ice. These thermal associations were determined before people understood that, as incandesence goes, red is really very cold. Red-hot was just about as hot as anybody could get anything for a long time. PJA 17:30, 19 December 2005 (UTC)
Though quite late (almost six years after), here some addition. According the German Wikipedia article cold colour the interpretation of blue has changed during the centuries. For the medieval Christian understanding, blue was considered warm, and commonly used as the colour of Maria. Similarly, a blue sky is sometimes associated with warm and sunny weather (especially if accompanied with a saturated green landscape), sometimes with the low temperatures at high altitudes (i.e. blues sky above snow-covered mountains). In connection with lighting it would be interesting to look for studies about the reception of light of different colour temperature. For example, I personally do not associate "warm white" with a warm and cosy atmosphere necessarily. Rather, my primary association is that of cold winter days where such orange-yellow light sources are required even at daytime, and where the sun sometimes hardly penetrates the haze, appearing as a yellowish to reddish, dull and blurry spot on the sky, rather than as the powerful white ball like which it appears in summer. On the other hand, I recently made the experience, that a fluorescent lamp with high color temperature (6500 K) does not necessarily appear "cold", but, in certain circumstances may cause even a tropical feeling (my first association after installing it in the bathroom was that of the beaches of Tenerife). This may also depend on the total lux value (the tropical feeling is much less in the much larger living room, using the same lamp). I have heard of at least a few statements (e.g. as online-posted customer's experiences with lamps, or on blogs about lighting) of people who feel similarly. To avoid original research, the next step would now be to retrieve such a study and post the results.-- SiriusB ( talk) 08:51, 24 October 2011 (UTC)
Why used color instead colour? The color is the American spelling. And the colour is the more frequent word then the color (Look at Macmillan English Dictionary, 2002).
There are not frequent of not frequent word. 'Color' is a american term, colour, an english one. As say Nareek, stay constant; if you use one term, keep it all along your article. -- luxorion
I agree, it should be translated from American into English. It would probabally make more sense to people. J ( talk) 14:07, 10 January 2010 (UTC)
The whole of Wikipedia should be so "translated". It is supposed to be an international, geography neutral resource, and like it or not, there are more speakers and writers of "English English" than "American English" in the world. To insist on American spellings is another example of US cultural imperialism. —Preceding unsigned comment added by 93.96.126.212 ( talk) 09:57, 14 January 2010 (UTC)
I believe that there is an error in this page. There where some example Kelvins are noted, I don't think the sky colors count as Black bodies. The blue color of the sky and the yellow color of the sun is actually due to refraction.
From Luxorion : see my answer at the end of this page. For short, you are completely right.
Mostly because of the Oxygen in the air, if I remember correctly. The oxygen has higher refration at the blue spectrum. That's why indirect, refracted light from the sun, all over the sky is blue and the rest of the direct light (image of the sun itself) lies in the yellow to orange (substraction of blue from a white light source gives yellow). Of course, if it's a very bright day, more of the unrefracted light comes from the direction of the sun and it looks whiter. The sun actually has about the same color continuously (except if you gonna count solar flares and solar activity changes). It's just its position in the sky (lower means more air, more refraction) and the composition of the sky (the wheather, height, .. ) that makes it change color (and consequently the color of the sky).
This can also be confirmed by the spectrum of the sky (the indirect light from the sun), it isn't a temperature color on itself! It's rather a refracted part of the spectrum of the sun. Can someone (confirm &) correct ?
R U Bn @ e-builds 13:24, 10 February 2006 (UTC)
This article explains it, its up to you to copy paste :)
http://members.shaw.ca/jimht03/light.html -Anon
While it may be true that the blue colour of the sky is due to a specific phenomenon not related to temperature (namely Rayleigh scattering), the fact remains that light colours can be correlated to black-body temperatures, and so it is still useful to speak of 'colour temperature' in relation to the appearance of the sky. The fact that photographers have produced the results desired by using reference to colour temperature in relation to daylight (and have done so for decades) merely reinforces the utility value of the concept, even though what is taking place here is a conceptual mapping from one physical phenomenon to another. Science and technology is, after all, replete with such useful conceptual mappings! Calilasseia 21:36, 16 March 2006 (UTC)
As you say, the underlying physics is different, but pale blue skies could be a reasonable approximation to a black-body colour, and thus be assigned a Correlated Colour Temperature. Deep blue skies however are simply nowhere near the blackbody locus and cannot be assigned a CCT.
57.66.65.38 09:32, 24 August 2006 (UTC) Andrew Steer
http://www.techmind.org/
Thanks, Calilasseia, you are very right. Though I also agree with Andrew Steer and I would add that the clear midday sun is also not very near BB. But maybe we need to reflect this.
Proposal: Let's just put between ( ) which resemble BBs and are not really a (appr.) BB source with for example (approc.) and (no BB source). Wayathink ?
R U Bn @ e-builds 13:34, 24 August 2006 (UTC)
Clear midday sun is not far off a blackbody for most practical colour-matching purposes. I took a nice spectrum from Surrey in England a few days ago - hopefully I can get that on the web sometime as it's a nice illustration :-) As to your last point, real BBs vs approx... recall "D65" is NOT the same as 6500K; 6500K is a blackbody colour while "D65" is a "standardised" daylight spectrum with colour close to a BB at 6500K. Similarly other "Dxx" colours - specified spectral power distributions defined by the CIE way back when! Fluorescents and discharge lamps are the ones which are nothing like BBs (and cause real headaches for colour-matching) - and it's the spikiness of the spectrum which prevents smooth filters from being able to balence the light. An arbitrary non-blackbody-colour source, as long as the spectrum is smooth, could be perfectly colour-corrected with a smooth-response filter on a camera. 80.189.152.198 22:01, 24 August 2006 (UTC)Andrew Steer http://www.techmind.org/
From Luxorion (ex-weatherman and pro-photographer among others) : I changed the text about black body and color of the sun in the paragraph were the previous author compared the color of the sun and the sky with the one of a BB brought over 6000 K... It is a non sense ! Only the effetive sun color depends on the BB. The color of the sun seen from the earth surface is only affected by refraction of sunlight and the color of the sky by Rayleigh scattering. See the text for comments. The rainbow graph of the sky from 0-15000 K or so should also be removed of moved elsewhere because it not related to the sky color but only to a black body. More explanations in French on LUXORION website How is it possible to let such errors on wiki !
An additional note: While it is correct that the sky colour is not caused by blackbody radiation, there is an interesting mathmatical similarity: Rayleigh scattering is proportional to the fourth power of the frequency (thus wavelength-4). This, however, is exactly the shape of the Planckian law of radiation for the limit of infinite temperature (which has a well-defined locus in the CIE colour space). For this reason, the blue sky can indeed be treated as a good approximation to a very hot blackbody resp. its shine on a distant white surface. This relationship would be exact for an equal-power spectrum. Since the Sun has a near-Planckian spectrum itself, the shape of the resulting spectrum is different (more green, less steep ascent towards blue, i.e. lower colour temperature at the blue end). But as the cited references in Standard Illuminant (in particular, Fig. 2 in Judd, MacAdam, Wyszecki (1964) on the sky colour spectra show, the approximation is still valid, and most sky colours are quite close (and typically slightly above, i.e. green-shifted with respect) to the Planckian locus curve.-- SiriusB ( talk) 09:15, 24 October 2011 (UTC)
I suppose we can't say xenon arc has color temperature because it is not produced by a back body.
Fluorescent lamps shouldn't not be referred as having color temperature. They do not have. One can say they have light characteristics that look like (?) another black body light source, but that's all. HMartins
The "common examples" of color temperature needs either citation, cleanup, or further explanation. Right now it lists:
... listing Daylight as *two* different colors, "average daylight" (whatever that means) as a third, and "effective sun temperature" as yet a fourth. That's confusing enough to be utterly unhelpful.
Unindenting.
Colorimetry is related to perception, but translated to objective physical measurements and calculations. Perception is variable and subjective; chromaticity and color temperature are not. But it's not really about physics per se, either, just a representation of a 3D subspace of spectrum space.
I think it's great that you're interested in working on improving the article. But improving it with information from reliable sources will be a better contribution; sourced material is usually correct, and usually lasts better, than stuff made up from what's in you head.
As to the "purely thermal" explanation of blackbodies, I think you made that up. It's not enough. Emissions from a low-pressure gas will be in discrete lines, nothing like a blackbody spectrum. That's why the sun has so many well known solar spectrum lines (actually the Fraunhofer lines are mostly absorption lines from cooler gases higher up in the solar atmosphere). Also see Solar variation.
I wasn't aware of the atronomical term effective temperature, but I see it's about stellar luminosity, not color. I don't think it has any place in this article, but if you find a source that connects it, then please do cite it.
As for importance of spectrum to Color-rendering index, you are correct. But that's not really very relevant to this article. Dicklyon 14:52, 12 September 2007 (UTC)
I just want to say this is an outstanding article. I've been trying to find the right color temperature to request LED lighting, and wanted to make sure I understand color temperature. It would be interesting, if someone has the information, to describe the differences in LED lighting (relating to color temperature, or CCT) as has been done with fluorescent. 206.124.31.24 17:39, 31 January 2007 (UTC)
Can someone explaine the difference in ratings between wikiprojects? - JWGreen 04:00, 15 March 2007 (UTC)
I have a question about the following statement made in this article.
"The power of a lightbulb (20 or 100 W) seems to change its color but in reality it only affects its luminosity (luminance) to which our eyes are very sensitive."
Is there a reference for this? This doesn't seem to agree with a statement in the Incandescent Light Bulb entry (see quote below), which infers that color temperature of tungsten lighting is variable.
"The current heats the filament to an extremely high temperature (typically 2000K to 3300K depending on the filament type, shape, size, and amount of current passed through). Heated atoms within the filament intensely vibrate. The electrons, which are charged particles now strongly oscilating, radiate excess energy in the form of black body radiation, according to Maxwell's equations."
I'm not saying that a 20W bulb and a 100W bulb couldn't have the same color temperature, it just means that they aren't necessarily the same since there is a lot of variability in filament temperatures for tungsten bulbs.
Furthermore, I have seen many photography websites which list color temperatures for tungsten lighting as a range, rather than a single value.
On a different (but related) subject, I would infer from the Incandescent Light Bulb entry that a dimmer switch will vary not only the luminosity of the bulb, but also the color temperature. This might be worth mentioning in this article. —The preceding unsigned comment was added by 202.33.240.34 ( talk) 02:00, 14 May 2007 (UTC).
Please get a real, full spectral power plot for incandescent lamp - don't cut it off at 700 nm!- 69.87.203.221 01:44, 26 May 2007 (UTC)
If anyone knows about LED lights and their color temperature, that is what i wondered next when reading this article. good job y'all; thx.
I added a fact tag to the colour temperature recommended range as I'm not sure how universally true it is. For example, I'm pretty sure Asians, at least East Asians and I think also South East Asians prefer a higher colour temperature then is the norm in the West. While I couldn't find any reliable sources to support this, these sources [1] & [2] do make the claim Nil Einne ( talk) 12:23, 23 August 2008 (UTC)
not sure where to put this, nor do i have a reference, although i'm sure one can be found: colour temperature of the light source is considered an important technical consideration in endoscopic surgery. the older tungsten light sources, developed for arthroscopic (joint) use are considered to have too low a light temp for belly and chest surgery. consequently, halogen sources are preferred. it has to do with energy emitted, particularly in the near-infrared spectrum, at a given luminosity. this is unimportant in joint surgery, because the space is continuously irrigated, preventing unwanted heating. in abdominal procedures, the cavity is inflated with co2.it is also said that visualization is superior with the higher colour temp. of halogen sources, but, frankly, i think that's splitting hairs. Toyokuni3 ( talk) 15:26, 3 November 2008 (UTC)
That should go in the article about that tool, not here. — Adoniscik( t, c) 16:30, 3 November 2008 (UTC)
The approximation equations for CCT appear helpful but are based on (x,y) coordinates; this seems to be counter to the statement "This (u,v) chromaticity space became the CIE 1960 color space, which is still used to calculate the CCT." Could someone clarify whether an approximation exists for the 1960 (u,v) coordinate system, similar to the approximation using 1931 (x,y) coordinates? Thanks! Jrtuenge ( talk) 21:19, 8 November 2008 (UTC)
This article is quite good, however, it took me quite a while to figure out what color temperature actually is, and I'm familiar with most concepts in physics so I should have been able to read the introductory paragraph and at least have an idea of what it is. However, the 3rd sentence, which I reworded (just moved words around) and marked with a vague tag because, well, it seemed pretty vague to me :p but I feel obliged to provide a reason for the vagueness. Specifically, the problems in the following sentence - "The temperature (usually measured in kelvins, K) is that source's color temperature at which the heated black-body radiator matches the color of the light source for a black body source" - this is my rewording, but it still is confusing that it uses 'temperature' and 'color temperature' without making it explicit whether the former is just a shortened form of color temp or if it refers to the temperature of either the black body source or the black body radiator (there was and is no mention elsewhere, at least in the intro, that would distinguish between these two pairs of similar words/phrases. Remember, the purpose of the introduction is to explain to a general reading population, i.e. in the simplest terms possible without sacrificing meaning, the essential nature of the topic at hand. As someone familiar with science and physics couldn't figure it out (that would be myself, heh) then the avg reader probably won't either. So if someone with knowledge of the topic (and grammatical skills, preferably) could reword that sentence further, to change it from semi-intelligible to intelligible, that person would have my gratitude as well as the knowledge of having earned good karma! Thanks in advance, if even just for reading this. Been trying to contribute to WP in more ways than just doing copy editing, and I figured "be bold," but I apologize if I actually screwed up the sentence by rewording it. Mr0t1633 ( talk) 12:15, 2 January 2010 (UTC)
I've come across many references saying daylight is standardized at 5500k or 5600k (I realize they're relatively arbitrary numbers). Who picked which number? What exactly are they used for? I don't think there are any relevant citations here? The closest I've found is that one of the CIE's standard daylight illuminants is 5503k. I've seen contradicting statements that each are the standard for the "film industry". Darxus ( talk) 22:09, 20 April 2010 (UTC)
(This comment was placed on the article page, but properly belongs on the talk page, so here it is)
Here is a typo which is important: "The general consensus is that "warm" colors promote flowering and setting of fruit, "warm" temperatures promote green growth." should read "The general consensus is that "warm" colors promote flowering and setting of fruit, "COOLItalic text" temperatures promote green growth." 72.227.96.103 ( talk) 12:09, 24 September 2010 (UTC)
Figure with caption "Close up of the CIE 1960 UCS" says that the color distance Delta_uv is of 0.05. This is incorrect, it actually is 0.0054. One can actually see that if it would be 0.05 it corresponds to one sixth of the graph, so this number is too big. I'm new user, sorry if I didn;t write following certain rules. — Preceding unsigned comment added by Vonromainoff ( talk • contribs) 23:19, 21 December 2010 (UTC)
Can someone fix the image please? I see that the issue has been mentioned on the image's page in 2010, but nothing has been done. —Preceding unsigned comment added by 41.6.62.247 ( talk) 09:06, 7 May 2011 (UTC)
Hello all, I have changed the table in the section [4] mentioned above and move studio lighting to the 3,200K range. Standard studio fixtures, such as the Arri ArriPlus650, Arri300, Mole Tweenie (500-650W), Mole Tweenie II, Mole Baby Junior SolarSpot (1K-2K), Bardwell McAlister MacLite 650, and numerous others use Tungsten Halogen bulbs with color temps of 3,200K (not 3,400K). The short list above (and their brethren in different wattage ranges), all come standard with 3,200K bulbs - and the standard replacements (such as the FRK650 for the Arri and Mole 650W) come standard at 3,200K as well. Though I am responsible for literally over a ton of such lighting and bulbs from various manufacturers, I am happy to provide references if needed. Best, ROBERTMFROMLI | TK/ CN 18:03, 22 July 2011 (UTC)
There is an important information missing: How is the deviation from the Planck blackbody curve and the best-fitting temperature calculated? In other words, what is the metric of the (u,v) space? If the metric is Euklidian, one could simply calculate the difference of squares, (u-uT)^2+(v-vT)^2, and find the temperature T for which it becomes minimal. The chart, however, suggests that one has to calculate the isotherms as orthogonal intersections to the Planck loci curve, and find the isotherm line whichs hits the actual color point. However, before adding something more or less obvious but yet unreferenced and thus doing "original research", it would be best if someone could find a freely available source (the CIE paper "The CIE definition of correlated color temperature" is, as apparently most CIE sources, either removed or no longer freely available and therefore useless to WP) which explains the method.-- SiriusB ( talk) 11:50, 5 September 2011 (UTC)
Why is the color temperature of the Moon so much lower than the solar color temperature? I guess that the Moon's own color is the cause, but this would imply that the Moon is of brownish od reddish color. But actually, it appears to be amlost neutral grey (not only to the eyes but also on many photographs, including the Apollo images) and should therefore have approximately the same color temperature (i.e. up to 5500 K near the zenith). Unfortunately, there seems to be little reliable information about the true color (i.e. without white balance) of the moon.-- SiriusB ( talk) 16:10, 28 September 2011 (UTC)
Additional note: I have now made some own measurements using a digital camera capable of RAW images. During a stay at Fuerteventura I took test photos of the full Moon (at about 37 degrees altitude corresponding to an air mass of 1.66) and determined the color temperature by using GIMP UFRAW 1. by automatic determination inside a frame around the Moon and 2. by setting the white point to 6500 K, RGB to linear (gamma=1) and then transforming RGB (assuming sRGB primaries) to CIE UCS 1960 and determined the color temperature. Both methods yielded very similar values around 4650 K, i.e. 500 K above the value the reference above states for the full moon "directly overhead". In addition, I calculated the CCT of several lunar reflectance spectra (e.g. from Kieffer & Stone (2005) which resulted in values up to 5000 K if filtered through the ASTMG173 solar spectrum (1.5 air masses, direct sunlight). Although this measurements/calculations alone are probaböy OR, it should at least be considered to check for other sources with more precise/reliable values. 4100 K seems to be too low for the near-zenith full moon.-- SiriusB ( talk) 10:23, 25 May 2013 (UTC)
I tried to calculate the correlated color temperature of the Sun based on spectra from ASTMG173 (extraterrestric) and (G2V, averaged). I used the method described here in the article, which gives accurate results for Planckian and D-Illuminant spectra. But in both true spectra the CCT was considerable higher than the well-known effective temperature of 5800 K. ASTMG173 corresponds to 5933 K, and HILIB G2V even in 6046 K (if compared in the same plot with same normalisations, the HILIB G2V spectrum is slightly reduced in the read around 600 nm while quite equal in the blue to green range. In the IR range it is slightly higher, but IR is ignored by the CIE 1931 tristimulus). It is true that realistic spectra are non-ideal blackbody spectra, and thus the CCT is different from the effective temperature. But if the difference is truely that large, this should be mentioned in some sources. If the CCT of pure direct sunlight (without the blues sky) from the zenith is about 5500 K a CCT of 6000 K would correspond to an atmospheric "color temperature" filter of +15 mireds, while for 5800 K Solar CCT it would be only +9 mireds.
As far as time permits I will look for reliable references for a 6000 K CCT of the Sun and, if positive, mention them in the article.-- SiriusB ( talk) 21:50, 13 June 2012 (UTC)
The sentence "Higher color temperatures are seen[by whom?] as getting through the water better,..." suggests that this is a subjective/unproven statement. However, isn't this a well-known fact that the blue portion gets better through water than the longer wavelengths? The choice of high-CCT light may also provide a more realistic simulation of the light conditions in real seawater, ten or more meters below the surface. A standard home aquarium, however, is probably not deep enough to filter the light. Therefore, the high-CCT light is rather to simulate the lighting in real waters rather than to enhance penetration in the actual aquarium. This is true for both freshwater and seawater (at the same depth), since the transmittance spectrum is, as far as I know, a property of the H2O molecule itself, not one of the salt content or other substances in natural water.-- SiriusB ( talk) 20:33, 29 July 2012 (UTC)
my understanding is that reflectance decreases with temperature, i.e. all materials become closer to perfectly black with increasing temperature. yet i don't see this mentioned anywhere - indeed i generally see reflectance being treated as a constant. if i am not wrong, perhaps someone with more knowledge could insert a paragraph or two — Preceding unsigned comment added by 110.175.57.184 ( talk) 03:07, 17 June 2013 (UTC)
it really should be cleaned up, in my opinion, so that an average layperson can read it and learn something or anything. 24.205.211.183 ( talk) 05:11, 27 April 2015 (UTC)
Being familiar with the various subjective color of light sources, I set my camera to live view and attempt to match the white balance in real time use the screen. I know that the bulb that lights the room is about 3500 kelvin. I input 3500 kelvin and the picture looks blue (more like 7000 kelvin). Why do they design the camera like that? Why not make 3500 kelvin LOOK LIKE 3500 kelvin. Having politely asked this question elsewhere, I get a lot of patronizing waffle as if I'm unfamiliar with what various color temperatures look like or wouldn't know in terms of photography - all of which is wrong by several decades. Does anyone actually know the reason why camea designers make 3500 kelvin blueish and 7000 kelvin reddish? Suggestion for the world's camera engineers and software developers: design a camera so that when the users recognizes and desires 3500 kelvin they get 3500 kelvin (not 7000 kelvin blueness). Thanks. — Preceding unsigned comment added by 31.55.127.254 ( talk) 22:51, 22 August 2015 (UTC)
This is an archive of past discussions. Do not edit the contents of this page. If you wish to start a new discussion or revive an old one, please do so on the current talk page. |
Archive 1 |
Right now this article mainly discusses the practical application of color temperature in cinematography -- we need information on the physics of it...
Agreed. But I don't know anything about the physics of it. -- Koyaanis Qatsi
Nice work anyway KQ! I really enjoyed reading it (OK, it does need the techie stuff though) - MMGB
yeh. and the prose needs a little work. but i'm off to bed now. :-) thanks, though. much appreciated. -- Koyaanis Qatsi
Added more physics-oriented discussion, made distinction between colour temperature and white balance. -- The Anome
Hehe - Article title "Color Temperature". First sentence "Colour temperature...". God I love this place. - MMGB
Yeh, it's great. Thanks, Anome, for adding the physics stuff. Sorry to use the term "loosely"; it's very common in the film & documentary industry. -- Koyaanis Qatsi
Yep, I know -- The Anome
Cinematographers don't/can't "white balance" in the same way as video camera operators: they can use techniques such as filters, pre-flashing, and after shooting, color grading (both by exposure at the labs, and also digitally, where digital film processes are used). This needs to be incorporated into the article. -- Anon.
Yes, it does need to be integrated into it. I've worked with both film and video, and noticed that, but never noticed the lack of coverage in the article. However, I'm off to bed now, so I'm glad to see you've added it. Thanks. :-) Koyaanis Qatsi 07:20 17 Jun 2003 (UTC)
Mark Sweep created pure art work from your basic start. I tried to help a little too. I want color temp to link like this, but I'm gettng the wrong words incandescent or incandescance, should link to the section called Incandescent Bulbs but [ "Incandescent" / "Incandescent Bulbs" ]]doesn't give me back my original word.gimma quick lessson please.I want to do this to fluorescence too.[User:Dkroll2|Dkroll2]]--[[User:Dkroll2| Dkroll2]] 04:09, Dec 14, 2004 (UTC)
All you need to do is write this: [[Incandescent light bulb|incandescent]] he pipe character "|" is used to show different text in a wikilink. Put the article name before the pipe, and the desired text of the link after the pipe. It'll show up like this: incandescent. But please remember that we only need to link the first time each term is used. There's no need to go through articles linking every instance of the term "incandescent". Rhobite 05:17, Dec 14, 2004 (UTC)
OOPS!//excuse me whilst I go fix a ton of stuff. DKroll2 OK you Color Temp guys got your physics, well some of it. Enough so It it didn't get too complex. I didnt agree about white balance and photography, since there are so many alternative applications, but at least you HAVE applications sections. AND I learned a bit mre about how white balance relates to color temp. thanks DKroll2
The plot showing a spectral power distribution looks representative of older "halophosphate" fluorescents, but not of the majority of modern tubes found in offices etc which use a newer "triphosphor" mix. My personal web page has a measured triphosphor spectrum (don't use as a wikipedia source!) http://www.techmind.org/colour/tld32w84hfsml.gif the key point being that the modern triphosphors have a very spikey spectrum with very little continuum at all. You may find emission spectra graphics from Philips/GE-Lighting/...
For spikey emission spectra, even if the overall colour were equivalent to a blackbody, the way it renders reflective (object) colours will always be "off" [colour-rendering issues - reflected colour arise from the product of the lightsource spectral power distribution and the object spectral reflectance]. Consequently, for photography it can still be impossible to properly colour-correct fluorescent light using filters.
I'll try and explain myself better and edit the article itself sometime.
57.66.65.38 12:58, 23 August 2006 (UTC) Andrew Steer ( http://www.techmind.org )
Question about citations.
I did 2 with success on those sections I wrote, but:
1: how many sections/paragraphs up from the citation is it valid? problem: I desire to find citations for my contributions, but not to some others, with whom I disagree, etc.
How do I limit my citations to my writings?
A thought: What if my writings are eventually rewritten, or even just editing incorrectly? The citation is invalid and is an insult to the cited author.
Hmmmm.--[[User:Dkroll2| Dkroll2]] 06:23, Dec 23, 2004 (UTC)
I fixed the link to Planck's Law, but I wondered if that shouldn't be Planck's_law_of_black_body_radiation? -- Lemming 21:57, 21 Jun 2005 (UTC)
hmm I've been thinking (not expert, just a question :) ) how does colour temperature relate to cold/warm colours? I mean, red is a "warm colour", and blue is a "white colour" but according to colour temperature, it's the opposite. Is there anyone who sees the problem (and can clear things)?
Our ideas about hot, warm, cool, and cold temperatures are psycological associations based on the common experiences of man since time immemorial. Red is the color of many things hot: fire, embers, lava, molten steel, even sunburned skin. Something "red-hot" is considered very, very hot. Orange and yellow, other "warm" colors, are also often seen in fire. Blue, on the other hand, is associated with water and ice. It's considered very cold. Green is associated with things like leaves and grass. These things are usually somewhat cool to the touch (they conduct heat away from your skin), but not cold like water and ice. These thermal associations were determined before people understood that, as incandesence goes, red is really very cold. Red-hot was just about as hot as anybody could get anything for a long time. PJA 17:30, 19 December 2005 (UTC)
Though quite late (almost six years after), here some addition. According the German Wikipedia article cold colour the interpretation of blue has changed during the centuries. For the medieval Christian understanding, blue was considered warm, and commonly used as the colour of Maria. Similarly, a blue sky is sometimes associated with warm and sunny weather (especially if accompanied with a saturated green landscape), sometimes with the low temperatures at high altitudes (i.e. blues sky above snow-covered mountains). In connection with lighting it would be interesting to look for studies about the reception of light of different colour temperature. For example, I personally do not associate "warm white" with a warm and cosy atmosphere necessarily. Rather, my primary association is that of cold winter days where such orange-yellow light sources are required even at daytime, and where the sun sometimes hardly penetrates the haze, appearing as a yellowish to reddish, dull and blurry spot on the sky, rather than as the powerful white ball like which it appears in summer. On the other hand, I recently made the experience, that a fluorescent lamp with high color temperature (6500 K) does not necessarily appear "cold", but, in certain circumstances may cause even a tropical feeling (my first association after installing it in the bathroom was that of the beaches of Tenerife). This may also depend on the total lux value (the tropical feeling is much less in the much larger living room, using the same lamp). I have heard of at least a few statements (e.g. as online-posted customer's experiences with lamps, or on blogs about lighting) of people who feel similarly. To avoid original research, the next step would now be to retrieve such a study and post the results.-- SiriusB ( talk) 08:51, 24 October 2011 (UTC)
Why used color instead colour? The color is the American spelling. And the colour is the more frequent word then the color (Look at Macmillan English Dictionary, 2002).
There are not frequent of not frequent word. 'Color' is a american term, colour, an english one. As say Nareek, stay constant; if you use one term, keep it all along your article. -- luxorion
I agree, it should be translated from American into English. It would probabally make more sense to people. J ( talk) 14:07, 10 January 2010 (UTC)
The whole of Wikipedia should be so "translated". It is supposed to be an international, geography neutral resource, and like it or not, there are more speakers and writers of "English English" than "American English" in the world. To insist on American spellings is another example of US cultural imperialism. —Preceding unsigned comment added by 93.96.126.212 ( talk) 09:57, 14 January 2010 (UTC)
I believe that there is an error in this page. There where some example Kelvins are noted, I don't think the sky colors count as Black bodies. The blue color of the sky and the yellow color of the sun is actually due to refraction.
From Luxorion : see my answer at the end of this page. For short, you are completely right.
Mostly because of the Oxygen in the air, if I remember correctly. The oxygen has higher refration at the blue spectrum. That's why indirect, refracted light from the sun, all over the sky is blue and the rest of the direct light (image of the sun itself) lies in the yellow to orange (substraction of blue from a white light source gives yellow). Of course, if it's a very bright day, more of the unrefracted light comes from the direction of the sun and it looks whiter. The sun actually has about the same color continuously (except if you gonna count solar flares and solar activity changes). It's just its position in the sky (lower means more air, more refraction) and the composition of the sky (the wheather, height, .. ) that makes it change color (and consequently the color of the sky).
This can also be confirmed by the spectrum of the sky (the indirect light from the sun), it isn't a temperature color on itself! It's rather a refracted part of the spectrum of the sun. Can someone (confirm &) correct ?
R U Bn @ e-builds 13:24, 10 February 2006 (UTC)
This article explains it, its up to you to copy paste :)
http://members.shaw.ca/jimht03/light.html -Anon
While it may be true that the blue colour of the sky is due to a specific phenomenon not related to temperature (namely Rayleigh scattering), the fact remains that light colours can be correlated to black-body temperatures, and so it is still useful to speak of 'colour temperature' in relation to the appearance of the sky. The fact that photographers have produced the results desired by using reference to colour temperature in relation to daylight (and have done so for decades) merely reinforces the utility value of the concept, even though what is taking place here is a conceptual mapping from one physical phenomenon to another. Science and technology is, after all, replete with such useful conceptual mappings! Calilasseia 21:36, 16 March 2006 (UTC)
As you say, the underlying physics is different, but pale blue skies could be a reasonable approximation to a black-body colour, and thus be assigned a Correlated Colour Temperature. Deep blue skies however are simply nowhere near the blackbody locus and cannot be assigned a CCT.
57.66.65.38 09:32, 24 August 2006 (UTC) Andrew Steer
http://www.techmind.org/
Thanks, Calilasseia, you are very right. Though I also agree with Andrew Steer and I would add that the clear midday sun is also not very near BB. But maybe we need to reflect this.
Proposal: Let's just put between ( ) which resemble BBs and are not really a (appr.) BB source with for example (approc.) and (no BB source). Wayathink ?
R U Bn @ e-builds 13:34, 24 August 2006 (UTC)
Clear midday sun is not far off a blackbody for most practical colour-matching purposes. I took a nice spectrum from Surrey in England a few days ago - hopefully I can get that on the web sometime as it's a nice illustration :-) As to your last point, real BBs vs approx... recall "D65" is NOT the same as 6500K; 6500K is a blackbody colour while "D65" is a "standardised" daylight spectrum with colour close to a BB at 6500K. Similarly other "Dxx" colours - specified spectral power distributions defined by the CIE way back when! Fluorescents and discharge lamps are the ones which are nothing like BBs (and cause real headaches for colour-matching) - and it's the spikiness of the spectrum which prevents smooth filters from being able to balence the light. An arbitrary non-blackbody-colour source, as long as the spectrum is smooth, could be perfectly colour-corrected with a smooth-response filter on a camera. 80.189.152.198 22:01, 24 August 2006 (UTC)Andrew Steer http://www.techmind.org/
From Luxorion (ex-weatherman and pro-photographer among others) : I changed the text about black body and color of the sun in the paragraph were the previous author compared the color of the sun and the sky with the one of a BB brought over 6000 K... It is a non sense ! Only the effetive sun color depends on the BB. The color of the sun seen from the earth surface is only affected by refraction of sunlight and the color of the sky by Rayleigh scattering. See the text for comments. The rainbow graph of the sky from 0-15000 K or so should also be removed of moved elsewhere because it not related to the sky color but only to a black body. More explanations in French on LUXORION website How is it possible to let such errors on wiki !
An additional note: While it is correct that the sky colour is not caused by blackbody radiation, there is an interesting mathmatical similarity: Rayleigh scattering is proportional to the fourth power of the frequency (thus wavelength-4). This, however, is exactly the shape of the Planckian law of radiation for the limit of infinite temperature (which has a well-defined locus in the CIE colour space). For this reason, the blue sky can indeed be treated as a good approximation to a very hot blackbody resp. its shine on a distant white surface. This relationship would be exact for an equal-power spectrum. Since the Sun has a near-Planckian spectrum itself, the shape of the resulting spectrum is different (more green, less steep ascent towards blue, i.e. lower colour temperature at the blue end). But as the cited references in Standard Illuminant (in particular, Fig. 2 in Judd, MacAdam, Wyszecki (1964) on the sky colour spectra show, the approximation is still valid, and most sky colours are quite close (and typically slightly above, i.e. green-shifted with respect) to the Planckian locus curve.-- SiriusB ( talk) 09:15, 24 October 2011 (UTC)
I suppose we can't say xenon arc has color temperature because it is not produced by a back body.
Fluorescent lamps shouldn't not be referred as having color temperature. They do not have. One can say they have light characteristics that look like (?) another black body light source, but that's all. HMartins
The "common examples" of color temperature needs either citation, cleanup, or further explanation. Right now it lists:
... listing Daylight as *two* different colors, "average daylight" (whatever that means) as a third, and "effective sun temperature" as yet a fourth. That's confusing enough to be utterly unhelpful.
Unindenting.
Colorimetry is related to perception, but translated to objective physical measurements and calculations. Perception is variable and subjective; chromaticity and color temperature are not. But it's not really about physics per se, either, just a representation of a 3D subspace of spectrum space.
I think it's great that you're interested in working on improving the article. But improving it with information from reliable sources will be a better contribution; sourced material is usually correct, and usually lasts better, than stuff made up from what's in you head.
As to the "purely thermal" explanation of blackbodies, I think you made that up. It's not enough. Emissions from a low-pressure gas will be in discrete lines, nothing like a blackbody spectrum. That's why the sun has so many well known solar spectrum lines (actually the Fraunhofer lines are mostly absorption lines from cooler gases higher up in the solar atmosphere). Also see Solar variation.
I wasn't aware of the atronomical term effective temperature, but I see it's about stellar luminosity, not color. I don't think it has any place in this article, but if you find a source that connects it, then please do cite it.
As for importance of spectrum to Color-rendering index, you are correct. But that's not really very relevant to this article. Dicklyon 14:52, 12 September 2007 (UTC)
I just want to say this is an outstanding article. I've been trying to find the right color temperature to request LED lighting, and wanted to make sure I understand color temperature. It would be interesting, if someone has the information, to describe the differences in LED lighting (relating to color temperature, or CCT) as has been done with fluorescent. 206.124.31.24 17:39, 31 January 2007 (UTC)
Can someone explaine the difference in ratings between wikiprojects? - JWGreen 04:00, 15 March 2007 (UTC)
I have a question about the following statement made in this article.
"The power of a lightbulb (20 or 100 W) seems to change its color but in reality it only affects its luminosity (luminance) to which our eyes are very sensitive."
Is there a reference for this? This doesn't seem to agree with a statement in the Incandescent Light Bulb entry (see quote below), which infers that color temperature of tungsten lighting is variable.
"The current heats the filament to an extremely high temperature (typically 2000K to 3300K depending on the filament type, shape, size, and amount of current passed through). Heated atoms within the filament intensely vibrate. The electrons, which are charged particles now strongly oscilating, radiate excess energy in the form of black body radiation, according to Maxwell's equations."
I'm not saying that a 20W bulb and a 100W bulb couldn't have the same color temperature, it just means that they aren't necessarily the same since there is a lot of variability in filament temperatures for tungsten bulbs.
Furthermore, I have seen many photography websites which list color temperatures for tungsten lighting as a range, rather than a single value.
On a different (but related) subject, I would infer from the Incandescent Light Bulb entry that a dimmer switch will vary not only the luminosity of the bulb, but also the color temperature. This might be worth mentioning in this article. —The preceding unsigned comment was added by 202.33.240.34 ( talk) 02:00, 14 May 2007 (UTC).
Please get a real, full spectral power plot for incandescent lamp - don't cut it off at 700 nm!- 69.87.203.221 01:44, 26 May 2007 (UTC)
If anyone knows about LED lights and their color temperature, that is what i wondered next when reading this article. good job y'all; thx.
I added a fact tag to the colour temperature recommended range as I'm not sure how universally true it is. For example, I'm pretty sure Asians, at least East Asians and I think also South East Asians prefer a higher colour temperature then is the norm in the West. While I couldn't find any reliable sources to support this, these sources [1] & [2] do make the claim Nil Einne ( talk) 12:23, 23 August 2008 (UTC)
not sure where to put this, nor do i have a reference, although i'm sure one can be found: colour temperature of the light source is considered an important technical consideration in endoscopic surgery. the older tungsten light sources, developed for arthroscopic (joint) use are considered to have too low a light temp for belly and chest surgery. consequently, halogen sources are preferred. it has to do with energy emitted, particularly in the near-infrared spectrum, at a given luminosity. this is unimportant in joint surgery, because the space is continuously irrigated, preventing unwanted heating. in abdominal procedures, the cavity is inflated with co2.it is also said that visualization is superior with the higher colour temp. of halogen sources, but, frankly, i think that's splitting hairs. Toyokuni3 ( talk) 15:26, 3 November 2008 (UTC)
That should go in the article about that tool, not here. — Adoniscik( t, c) 16:30, 3 November 2008 (UTC)
The approximation equations for CCT appear helpful but are based on (x,y) coordinates; this seems to be counter to the statement "This (u,v) chromaticity space became the CIE 1960 color space, which is still used to calculate the CCT." Could someone clarify whether an approximation exists for the 1960 (u,v) coordinate system, similar to the approximation using 1931 (x,y) coordinates? Thanks! Jrtuenge ( talk) 21:19, 8 November 2008 (UTC)
This article is quite good, however, it took me quite a while to figure out what color temperature actually is, and I'm familiar with most concepts in physics so I should have been able to read the introductory paragraph and at least have an idea of what it is. However, the 3rd sentence, which I reworded (just moved words around) and marked with a vague tag because, well, it seemed pretty vague to me :p but I feel obliged to provide a reason for the vagueness. Specifically, the problems in the following sentence - "The temperature (usually measured in kelvins, K) is that source's color temperature at which the heated black-body radiator matches the color of the light source for a black body source" - this is my rewording, but it still is confusing that it uses 'temperature' and 'color temperature' without making it explicit whether the former is just a shortened form of color temp or if it refers to the temperature of either the black body source or the black body radiator (there was and is no mention elsewhere, at least in the intro, that would distinguish between these two pairs of similar words/phrases. Remember, the purpose of the introduction is to explain to a general reading population, i.e. in the simplest terms possible without sacrificing meaning, the essential nature of the topic at hand. As someone familiar with science and physics couldn't figure it out (that would be myself, heh) then the avg reader probably won't either. So if someone with knowledge of the topic (and grammatical skills, preferably) could reword that sentence further, to change it from semi-intelligible to intelligible, that person would have my gratitude as well as the knowledge of having earned good karma! Thanks in advance, if even just for reading this. Been trying to contribute to WP in more ways than just doing copy editing, and I figured "be bold," but I apologize if I actually screwed up the sentence by rewording it. Mr0t1633 ( talk) 12:15, 2 January 2010 (UTC)
I've come across many references saying daylight is standardized at 5500k or 5600k (I realize they're relatively arbitrary numbers). Who picked which number? What exactly are they used for? I don't think there are any relevant citations here? The closest I've found is that one of the CIE's standard daylight illuminants is 5503k. I've seen contradicting statements that each are the standard for the "film industry". Darxus ( talk) 22:09, 20 April 2010 (UTC)
(This comment was placed on the article page, but properly belongs on the talk page, so here it is)
Here is a typo which is important: "The general consensus is that "warm" colors promote flowering and setting of fruit, "warm" temperatures promote green growth." should read "The general consensus is that "warm" colors promote flowering and setting of fruit, "COOLItalic text" temperatures promote green growth." 72.227.96.103 ( talk) 12:09, 24 September 2010 (UTC)
Figure with caption "Close up of the CIE 1960 UCS" says that the color distance Delta_uv is of 0.05. This is incorrect, it actually is 0.0054. One can actually see that if it would be 0.05 it corresponds to one sixth of the graph, so this number is too big. I'm new user, sorry if I didn;t write following certain rules. — Preceding unsigned comment added by Vonromainoff ( talk • contribs) 23:19, 21 December 2010 (UTC)
Can someone fix the image please? I see that the issue has been mentioned on the image's page in 2010, but nothing has been done. —Preceding unsigned comment added by 41.6.62.247 ( talk) 09:06, 7 May 2011 (UTC)
Hello all, I have changed the table in the section [4] mentioned above and move studio lighting to the 3,200K range. Standard studio fixtures, such as the Arri ArriPlus650, Arri300, Mole Tweenie (500-650W), Mole Tweenie II, Mole Baby Junior SolarSpot (1K-2K), Bardwell McAlister MacLite 650, and numerous others use Tungsten Halogen bulbs with color temps of 3,200K (not 3,400K). The short list above (and their brethren in different wattage ranges), all come standard with 3,200K bulbs - and the standard replacements (such as the FRK650 for the Arri and Mole 650W) come standard at 3,200K as well. Though I am responsible for literally over a ton of such lighting and bulbs from various manufacturers, I am happy to provide references if needed. Best, ROBERTMFROMLI | TK/ CN 18:03, 22 July 2011 (UTC)
There is an important information missing: How is the deviation from the Planck blackbody curve and the best-fitting temperature calculated? In other words, what is the metric of the (u,v) space? If the metric is Euklidian, one could simply calculate the difference of squares, (u-uT)^2+(v-vT)^2, and find the temperature T for which it becomes minimal. The chart, however, suggests that one has to calculate the isotherms as orthogonal intersections to the Planck loci curve, and find the isotherm line whichs hits the actual color point. However, before adding something more or less obvious but yet unreferenced and thus doing "original research", it would be best if someone could find a freely available source (the CIE paper "The CIE definition of correlated color temperature" is, as apparently most CIE sources, either removed or no longer freely available and therefore useless to WP) which explains the method.-- SiriusB ( talk) 11:50, 5 September 2011 (UTC)
Why is the color temperature of the Moon so much lower than the solar color temperature? I guess that the Moon's own color is the cause, but this would imply that the Moon is of brownish od reddish color. But actually, it appears to be amlost neutral grey (not only to the eyes but also on many photographs, including the Apollo images) and should therefore have approximately the same color temperature (i.e. up to 5500 K near the zenith). Unfortunately, there seems to be little reliable information about the true color (i.e. without white balance) of the moon.-- SiriusB ( talk) 16:10, 28 September 2011 (UTC)
Additional note: I have now made some own measurements using a digital camera capable of RAW images. During a stay at Fuerteventura I took test photos of the full Moon (at about 37 degrees altitude corresponding to an air mass of 1.66) and determined the color temperature by using GIMP UFRAW 1. by automatic determination inside a frame around the Moon and 2. by setting the white point to 6500 K, RGB to linear (gamma=1) and then transforming RGB (assuming sRGB primaries) to CIE UCS 1960 and determined the color temperature. Both methods yielded very similar values around 4650 K, i.e. 500 K above the value the reference above states for the full moon "directly overhead". In addition, I calculated the CCT of several lunar reflectance spectra (e.g. from Kieffer & Stone (2005) which resulted in values up to 5000 K if filtered through the ASTMG173 solar spectrum (1.5 air masses, direct sunlight). Although this measurements/calculations alone are probaböy OR, it should at least be considered to check for other sources with more precise/reliable values. 4100 K seems to be too low for the near-zenith full moon.-- SiriusB ( talk) 10:23, 25 May 2013 (UTC)
I tried to calculate the correlated color temperature of the Sun based on spectra from ASTMG173 (extraterrestric) and (G2V, averaged). I used the method described here in the article, which gives accurate results for Planckian and D-Illuminant spectra. But in both true spectra the CCT was considerable higher than the well-known effective temperature of 5800 K. ASTMG173 corresponds to 5933 K, and HILIB G2V even in 6046 K (if compared in the same plot with same normalisations, the HILIB G2V spectrum is slightly reduced in the read around 600 nm while quite equal in the blue to green range. In the IR range it is slightly higher, but IR is ignored by the CIE 1931 tristimulus). It is true that realistic spectra are non-ideal blackbody spectra, and thus the CCT is different from the effective temperature. But if the difference is truely that large, this should be mentioned in some sources. If the CCT of pure direct sunlight (without the blues sky) from the zenith is about 5500 K a CCT of 6000 K would correspond to an atmospheric "color temperature" filter of +15 mireds, while for 5800 K Solar CCT it would be only +9 mireds.
As far as time permits I will look for reliable references for a 6000 K CCT of the Sun and, if positive, mention them in the article.-- SiriusB ( talk) 21:50, 13 June 2012 (UTC)
The sentence "Higher color temperatures are seen[by whom?] as getting through the water better,..." suggests that this is a subjective/unproven statement. However, isn't this a well-known fact that the blue portion gets better through water than the longer wavelengths? The choice of high-CCT light may also provide a more realistic simulation of the light conditions in real seawater, ten or more meters below the surface. A standard home aquarium, however, is probably not deep enough to filter the light. Therefore, the high-CCT light is rather to simulate the lighting in real waters rather than to enhance penetration in the actual aquarium. This is true for both freshwater and seawater (at the same depth), since the transmittance spectrum is, as far as I know, a property of the H2O molecule itself, not one of the salt content or other substances in natural water.-- SiriusB ( talk) 20:33, 29 July 2012 (UTC)
my understanding is that reflectance decreases with temperature, i.e. all materials become closer to perfectly black with increasing temperature. yet i don't see this mentioned anywhere - indeed i generally see reflectance being treated as a constant. if i am not wrong, perhaps someone with more knowledge could insert a paragraph or two — Preceding unsigned comment added by 110.175.57.184 ( talk) 03:07, 17 June 2013 (UTC)
it really should be cleaned up, in my opinion, so that an average layperson can read it and learn something or anything. 24.205.211.183 ( talk) 05:11, 27 April 2015 (UTC)
Being familiar with the various subjective color of light sources, I set my camera to live view and attempt to match the white balance in real time use the screen. I know that the bulb that lights the room is about 3500 kelvin. I input 3500 kelvin and the picture looks blue (more like 7000 kelvin). Why do they design the camera like that? Why not make 3500 kelvin LOOK LIKE 3500 kelvin. Having politely asked this question elsewhere, I get a lot of patronizing waffle as if I'm unfamiliar with what various color temperatures look like or wouldn't know in terms of photography - all of which is wrong by several decades. Does anyone actually know the reason why camea designers make 3500 kelvin blueish and 7000 kelvin reddish? Suggestion for the world's camera engineers and software developers: design a camera so that when the users recognizes and desires 3500 kelvin they get 3500 kelvin (not 7000 kelvin blueness). Thanks. — Preceding unsigned comment added by 31.55.127.254 ( talk) 22:51, 22 August 2015 (UTC)