Talk:Mired

Untitled
I think some correction is needed here.

My understanding is that the relationship between mireds (M) and colour temperature (T) is given by the equation:

$$M=\frac{1000000}{T}$$

Therefore writing:

"equals 1,000,000 (one million) divided by the reciprocal of a given color temperature" (my emphasis)

as originally appeared in the article is incorrect, as this would imply:

$$M=\frac{1000000}{1/T}$$

The first formula above generates the correct mired values, so that for T=10000K, M=100, for T=12000, M=83.3333, and for T=6000, M=166.6667 (to 4 decimal places). The second formula generates incorrect results, and is effectively the same as:

$$M=1000000 \times T$$

I am therefore editing this article accordingly. If anyone wishes to give my edit an overview a check, feel free. I also think that a link to this article from the colour temperature article is needed, as photographers will expect this, and the fact that mired and colour temperature are closely related in the world of photography should be present in the latter article.

Ack. forgot to add my user name tildes! Calilasseia 18:50, 12 January 2006 (UTC)

A pronunciation guide would be useful. 128.186.111.146 18:02, 14 September 2006 (UTC)
 * It's pronounced "my-red". How else could it be pronounced? 83.104.249.240 (talk) 00:11, 10 May 2009 (UTC)

How is mirek a contraction of reciprocal megaKelvin? Surely it's a contraction of micro reciprocal Kelvin. 83.104.249.240 (talk) 00:11, 10 May 2009 (UTC)
 * Am I right to assume that mirek === mired? The article says mirek is the S.I. unit but not how it's defined. If it is defined as 1000000/K, that would be neither reciprocal megakelvin nor micro reciprocal kelvin, but mega reciprocal kelvin: merek. Or reciprocal microkelvin: remik. How could the SI ever standardize something with such a flawed definition?--92.78.102.252 (talk) 21:59, 28 June 2010 (UTC)

To the pronunciation issue: After a quick Google search I found two pronunciations: "my-red" and "my-r'd" (approx. like the adjective "mired", i.e. the "e" not spoken; see this posting at [www.openphotographyforums.com]). But the first one seems to be more frequent.--SiriusB (talk) 11:20, 12 August 2012 (UTC)

Nonsense, improper use of prefixes
The article says
 * "1 mired is equivalent to 106 K&minus;1 or MK&minus;1."

The first problem is improperly starting a sentence with a numeral.

But the biggest problem is that it is self-contradictory and false.

At the very least it isn't following the rules for using unit prefixes and exponents. If it is 106 K&minus;1, which is $$\frac{10^6}{1 \ \mathrm{K}}$$, then moving the number from the numerator to the denominator, that is the same as
 * $$\frac{1}{10^{-6} \ \mathrm{K}}$$

since 1,000,000 = 1/0.000001, or with the exponents, 106 = 1/10−6, and then we can replace $$10^{-6}$$ with the symbol for micro- to get
 * $$\frac{1}{1\ \mu \mathrm{K}} = 1 \ \mu \mathrm{K}^{-1}$$,

In other words, it is 1 µK−1 not 1 MK−1, if the 106 K&minus;1 is correct.

But I don't know if the error occurs on the left side (maybe the exponent 6 is supposed to be −6) of the equal sign, or on the right side as assumed above. Is there anybody who does know who can fix this, please? Gene Nygaard (talk) 02:44, 7 February 2010 (UTC)

"T is the color temperature in kelvins" Incorrect English?
Surely that should be "T is the color temperature in degrees Kelvin" Or is this an US English thing? Or am I just plain wrong? (I've seen "kelvins" elsewhere on Wikipedia too) BrianDGregory (talk) 23:50, 6 March 2010 (UTC)
 * Elsewhere on Wikipedia: Unlike the degree Fahrenheit and degree Celsius, the kelvin is not referred to as a "degree"--92.78.102.252 (talk) 21:46, 28 June 2010 (UTC)

Negative mired values?
Is there any logical (albeit non-physical) extension towards negative mired values? The chromaticity allows an extension by simply extrapolating the Planckian Locus, but proper extrapolations would require some mathematical description which is continuous and differentiable at 0 mired. The motivation of this is that the color of a perfect sky (i.e. following ideal Rayleigh scattering) illuminated by an equal-energy illuminant would be the same as that of black body at infinite temperature, since both Rayleigh scattering and the Rayleigh-Jeans law (which becomes applicable for all wavelength for high enough temperatures) are a &lambda;-4 power law. Thus, with standard illuminant E having a correlated color temperature of 183 mireds, and a infinitely hot black body has 0 mireds, the "super-Planckian" light of a perfect sky illuminated by a very hot illuminant (e.g. a planet with atmosphere orbiting an O-type star), with approx. &lambda;-8, would have about -183 mireds. For intinite negative mired values the chromaticity should asymptotically approximate the violet point at the far left end of the "purple line" in the CIE color space (i.e. that of monochromatic light at about 380 nm). The straight-forward idea to extend the Planck law by a power-law with power>4 fits the latter condition, but fails the requirement of being differentiable at 0 mireds (both curves show similar but yet diffent slopes). In contrast, just expanding Planck's law for negative temperatures would make the exp(*)-1 term negative and thus result in a negative SED, whichs does not make sense. The whole idea may look a bit academic, but the given example of the sky of a planet orbiting an O star is indeed a possible (although not probable) one. Furthermore, in photography there might be the requirement of filters or corrections that can deal with extremely violet-biased light sources (e.g. LEDs without phosphor), which could be approximated by a negative (correlated) mired value. I tried to search for this problem via Google, but didn't get any results to this.--SiriusB (talk) 14:21, 16 February 2012 (UTC)

Proposed article name change to "Reciprocal Megakelvins"
The term "mired" has been deprecated for a half-century, and has been replaced by the SI-compliant "reciprocal megakelvin." It it therefore proposed:

1. The article be renamed "Reciprocal Megakelvin;"

2. The page "Mired" be established as a re-direct to the correctly-named page;

3. The deprecated term "mired" be changed to the correct term throughout the article, expect when appearing in the title of a reference or in a direct quotation;

and

4. An explanatory note regarding the deprecation of "mired" be provided.

2603:7080:9600:9BEE:B9B0:F6C3:6D61:7FF2 (talk) 01:57, 16 October 2022 (UTC)


 * Please cite sources for your proposed change. Adakiko (talk) 04:06, 16 October 2022 (UTC)
 * We have WP:COMMONNAME here. According to a 2005 source, "this term has not gained traction". Artoria2e5 🌉 13:38, 23 January 2024 (UTC)