Talk:Color rendering index: Difference between revisions

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== Obsolete merge proposal ==

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Oppose -- CRI is a very specific and measurable quality of light. Perhaps a better solution would be to create a more general "Color Rendering qualities of Light" topic wherein various measurables both quanititive and qualitative could be discussed <!-- Template:Unsigned IP --><small class="autosigned">—&nbsp;Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[Special:Contributions/161.88.255.139|161.88.255.139]] ([[User talk:161.88.255.139#top|talk]]) 17:43, 2 May 2006 (UTC)</small>

Agree in part -- CRI is a terrible metric to use by any lighting expert's standards. However it is specific and important for historic reasons. Not to mention it's dominance in household products. CRI deserves to remain a page perhaps with the heading "CIE Color Rendering Index" to more specifically refer to the named standard. A new page on the topic of color rendering should be written using the following definition "The property of a lighting fixture which describes how the light it produces will affect the appearance of colored materials" [[User:TDcolor|TDcolor]] ([[User talk:TDcolor|talk]]) 19:39, 2 January 2021 (UTC)

== Request: Add still photo to the "Film and video high-CRI LED lighting incompatibility" section. ==

== New test color samples section ==

The "Film and video high-CRI LED lighting incompatibility" section describes the applicability of CRI scores to film and video results. Still digital photography is not specifically mentioned. Could such material be added? <!-- Template:Unsigned --><small class="autosigned">—&nbsp;Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[User:Dmk5717|Dmk5717]] ([[User talk:Dmk5717#top|talk]] • [[Special:Contributions/Dmk5717|contribs]]) 17:52, 3 June 2019 (UTC)</small> <!--Autosigned by SineBot-->

The harv templates really mess with the flow of the text, since they display in parentheses, yet are used as important words or phrases in sentences. Looks like murder to fix... [[User:Huw Powell|Huw Powell]] ([[User talk:Huw Powell|talk]]) 01:23, 18 January 2011 (UTC)

== Request Move / Re-org ==

:I agree; it never makes sentence to try to use a ref as a noun in a sentence, but editors do that all the time. [[User:Dicklyon|Dicklyon]] ([[User talk:Dicklyon|talk]]) 05:36, 18 January 2011 (UTC)

Hi all. Like the above very old merge request mentions. There are numerous reasons why this page needs extensive editing.

:I did some work on it. Let's see if anyone objects before we do a lot more. [[User:Dicklyon|Dicklyon]] ([[User talk:Dicklyon|talk]]) 05:58, 18 January 2011 (UTC)

1) The topic of "Color Rendering" in color science / lighting science has come to mean much much more than the CIE CRI standard.

:: Is anyone especially attached to the Harvard citations? I much prefer sticking a footnote at the end of each paragraph or so, and just writing “John Doe 2010, p. 50” or whatever in the footnote for each source already listed in the Bibliography/Sources section. Also, I think it works best when the sources listed in their own section (here called “Sources” but sometimes called “Further Reading” or “Bibliography”) are either especially comprehensive/readable, or else the most important original sources for some topic. Then putting a source in that section becomes a bit of an endorsement, suggesting that readers might turn to those sources first before venturing into the forest of papers. Finally, in general, I think littering an article with phrases like “as described by so-and-so 2000” is unnecessary, unless the author’s name is so important/relevant to the topic that it deserves special mention. Many of the sentences with such phrases in this article would be supportable by many sources, and so calling out the specific authors doesn’t seem worth the extra clutter and emphasis. I don’t ''especially'' mind Harvard citations – if the page’s main authors like them I’m not going to complain about their volunteer writing efforts – but I avoid them if I’m writing an article. –[[user:jacobolus|jacobolus]] [[User_talk:jacobolus|(t)]] 08:03, 18 January 2011 (UTC)

2) The CIE no longer endorses the use of CRI although has not replaced it. In 2015 they endorsed the IES TM-30 standard

== Missing definition in chromatic adaption section ==

3) Many of the "alternatives" are not really contenders in the lighting community. SSI, TLCI, and TM-30 are pretty much the only 3 new standards that matter to a wide audience at this point.

The variables <math>c_{r,i}, d_{r,i}</math> and <math>c_{t,i}, d_{t,i}</math>are not properly introduced. While the indices ''r'' and ''t'' refer to the reference and the test light source, ''i'' refers to the test color. However, it is not explained what the connection of ''r,i'' or ''t,i'' means. If it refers to the '''apparent''' chromaticity of the ''i''th source color illuminated by light type ''r'' or ''t'', this should be explained explicitely and unambigously.--[[User:SiriusB|SiriusB]] ([[User talk:SiriusB|talk]]) 15:08, 6 January 2012 (UTC)

Therefore I think a page specifically called "Color Rendering" should be created which just defines the topic provides a paragraph overview of the most important standards and links to their pages. Important specific pages would, at the very least include "CRI, TLCI, TM-30", and "SSI".

:Solved so far. The web reference which contains the Matlab script clarifies the question.

I am happy to work on these articles but I'm a new wikipedian, I don't know the best ways to go about this.

:However, there is now another question: Where do the numbers in the example calculation come from? Are they extracted from some citeable reference or derived by numerical means? If the former is true, please give all references. If the latter is true, please give a detailed description of methods and sources, in particular: 1. The source for the F4 spectrum, 2. the numerical method for the chromaticity calculation (especially whether discrete values for e.g. 5 nm steps are added or an accurate interpolation and quadrature algorithm, e.g. cubic splines and Simpson's integration rule or better, is used. Inaccurate, non-repeatable description of the methods may render this part as original research. I have made calculations on this topic and found very good agreement but, however, no exact match of the particular DeltaUVW or Ri values. In addition, I can almost exactly reproduce the chromaticities for all F spectra with F4 as the only exception; source of data is one of the (equivalent) weblinks given at the and of the article.--[[User:SiriusB|SiriusB]] ([[User talk:SiriusB|talk]]) 20:49, 15 November 2012 (UTC)

Lastly, since part of what I am discussing doesn't have a clear place for content like the CQS paragraphs, I would move these to the "Color Rendering" topic page in some kind of "other alternatives" just so that interested readers could know that they are out there and have some search terms for them. I'm not willing, at this time, to cover those in depth.

:: Agreed; I've just spent two days trying to get these results to come out and too many steps are skipped to see where it's going wrong. Even fudging and playing with the significant figure requirements, I can't get the results to come out closer than several percent. The von Kries adaptation step especially goes wrong, even using the values directly out of the table from the preceding step. <span style="font-size: smaller;" class="autosigned">— Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[Special:Contributions/71.232.13.18|71.232.13.18]] ([[User talk:71.232.13.18|talk]]) 20:36, 16 September 2014 (UTC)</span><!-- Template:Unsigned IP --> <!--Autosigned by SineBot-->

[[User:TDcolor|TDcolor]] ([[User talk:TDcolor|talk]]) 19:48, 2 January 2021 (UTC)

== Typical values / Light Source Chart ==

:I see this article as only for CRI per its name. I am confused why it jumps to talking about color rendering in general. I think a separate article called '''Color rendering''' that discusses color rendering in general with this article linking back to that would make this page cleaner and the topics easier to understand. --[[User:tonsofpcs|tonsofpcs]] _{([[User talk:tonsofpcs|Talk]])} 03:20, 5 January 2021 (UTC)

Can regular incandescent bulbs be added to the Typical values / Light Source Chart? I can't tell if the last entry of incandescent/halogen refers to ordinary (classical) incandescent bulbs or only to the newer halogen bulbs. Do designations such as "soft white" etc. have differing CRI values? I notice a particlar LED-based bulb advertised as CRI of 80. This seems low. Is this typical? Thanks! --[[User:Lbeaumont|Lbeaumont]] ([[User talk:Lbeaumont|talk]]) 15:30, 5 March 2012 (UTC)

:'''Support''' the creation of a separate [[Color rendering]] article. {{U|TDcolor}}, I've finished stubbing the target article out, but I am afraid I don't have time to do the reorganization (i.e. move stuff there) for now. --[[User:Artoria2e5|Artoria]][[User talk:Artoria2e5|2e5]] <small style="font-weight:lighter">[[Special:Contributions/Artoria2e5|🌉]]</small> 06:09, 15 November 2021 (UTC)

::Thanks. It's a good change. I like the new article. I'd love to contribute more but it's kind of difficult scheduling and I'm a new wikipedian. Great to pull out the different relevant standards in a bulleted list. Mainly material needs to get moved from this article into the new article, then this needs to get parred down just to the text of the CIE document for color rendering index. I'll have to look up the relevant standards later. [[User:TDcolor|TDcolor]] ([[User talk:TDcolor|talk]]) 18:49, 14 March 2022 (UTC)

== Downgrade to C ==

:Typical incandescents have a CCT of about 2700K, but still a CRI of 100 by definition. See [http://books.google.com/books?id=ax_MgxXtTa8C&pg=PA132 this book page]. [[User:Dicklyon|Dicklyon]] ([[User talk:Dicklyon|talk]]) 15:41, 5 March 2012 (UTC)

I have downgraded this article to "C" for two reasons:

== Ra8, Ra14 ==

1) It does not contain up-to-date information on the status of CRI in the lighting science community where it has become highly frowned upon.

There is no mention of the Ra8 and Ra14 standards. -- [[User:Frap|Frap]] ([[User talk:Frap|talk]]) 14:44, 14 May 2012 (UTC)

:Ra8 seems to be the same as the Ra described in the artivle (averaged over the first 8 colors), while Ra14 should be the same with all 14 colors. BTW the German [[Stiftung Warentest]] uses both the standard Ra and the R₉ (red) index (or maybe an Ra9 equivalent to Ra but also includes TCS9) to judge the color rendition since red color hues are a typical but serious weak point of many fluorescent and LED lamps--[[User:SiriusB|SiriusB]] ([[User talk:SiriusB|talk]]) 20:58, 15 November 2012 (UTC)

2) It contains dissorganized or out of place information about alternatives that either needs to be cleaned up or replaced with a better topic page / structure.

== External links modified ==

Please see '''Request Move / Re-org''' for suggestions.

Hello fellow Wikipedians,

[[User:TDcolor|TDcolor]] ([[User talk:TDcolor|talk]]) 19:53, 2 January 2021 (UTC)

I have just added archive links to {{plural:1|one external link|1 external links}} on [[Color rendering index]]. Please take a moment to review [https://en.wikipedia.org/w/index.php?diff=prev&oldid=712760728 my edit]. You may add {{tlx|cbignore}} after the link to keep me from modifying it, if I keep adding bad data, but formatting bugs should be reported instead. Alternatively, you can add {{tlx|nobots|deny{{=}}InternetArchiveBot}} to keep me off the page altogether, but should be used as a last resort. I made the following changes:

*Attempted to fix sourcing for http://physics.nist.gov/Divisions/Div844/facilities/vision/color.html

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How does having a high CRI affect health compared to lower CRI? [[Special:Contributions/198.52.172.227|198.52.172.227]] ([[User talk:198.52.172.227|talk]]) 08:37, 8 April 2022 (UTC)

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== TCS15 / R15 for skin tones? ==

Cheers.—[[User:Cyberbot II|<sup style="color:green;font-family:Courier">cyberbot II</sup>]]<small><sub style="margin-left:-14.9ex;color:green;font-family:Comic Sans MS">[[User talk:Cyberbot II|<span style="color:green">Talk to my owner</span>]]:Online</sub></small> 23:56, 30 March 2016 (UTC)

The "Test color samples" of the article talks about a 14 color scale. But a 15th color (TCS15, 1YR6/4) for skin tones is often cited as part of CRI. It's mentioned later in the Wikipedia article. I'm not a ___domain expert but I gather this is a recent addition. Should it be included with the other 14 samples? [[User:Nelson Minar|Nelson Minar]] ([[User talk:Nelson Minar|talk]]) 16:54, 30 March 2023 (UTC)

==References==

There are currently five sources involving the same set of authors (R. Dangol, M. Islam, M. Hyvärinen, P. Bhusal, M. Puolakka, and L. Halonen). Are these authors so prominent in this field that one quarter of all sources are written by them? Or is this another case of [[WP:REFSPAM|refspamming]]? <font color="#8b4513">[[User:Mindmatrix|Mind]]</font><font color="#ee8811">[[User_talk:Mindmatrix|matrix]]</font> 14:41, 7 November 2016 (UTC)

:imho definitely refspamming <!-- Template:Unsigned IP --><small class="autosigned">—&nbsp;Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[Special:Contributions/131.155.212.62|131.155.212.62]] ([[User talk:131.155.212.62#top|talk]]) 09:22, 9 October 2017 (UTC)</small> <!--Autosigned by SineBot-->

:: I am Also a researcher in the field and have never heard of them. However it seems this is obsolete. I'm new to wiki, can it be removed from the talk page? [[User:TDcolor|TDcolor]] ([[User talk:TDcolor|talk]]) 15:07, 30 December 2020 (UTC)

== Proposed merge of [[High-CRI LED lighting]] into [[Color rendering index]] ==

== External links modified ==

{{Discussion top|result=To '''not merge''', but to refine [[High-CRI LED lighting]] to reduce duplication there, then link to this page for more detail. [[User:Klbrain|Klbrain]] ([[User talk:Klbrain|talk]]) 10:51, 5 October 2023 (UTC)}}

Wide overlap and duplication. [[User:Fgnievinski|fgnievinski]] ([[User talk:Fgnievinski|talk]]) 05:16, 10 April 2023 (UTC)

:This seems like a bad idea. These are two completely different subjects. One is about a kind of lamps, and the other is about a standard metric by which lamps can be measured. The High-CRI LEDs article should be slimmed down and refocused on the details of the lamps rather than on explaining the CRI. ––[[user:jacobolus|jacobolus]] [[User_talk:jacobolus|(t)]] 07:08, 10 April 2023 (UTC)

Hello fellow Wikipedians,

::That makes sense to me--to slim down the high CRI LEDs article and refer readers to this one more as needed. [[User:Ccrrccrr|Ccrrccrr]] ([[User talk:Ccrrccrr|talk]]) 02:26, 12 April 2023 (UTC)

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*Added archive https://web.archive.org/web/20110718171338/http://www.lrc.rpi.edu/programs/solidstate/assist/recommends/lightcolor.asp to http://www.lrc.rpi.edu/programs/solidstate/assist/recommends/lightcolor.asp

*Added archive https://web.archive.org/web/20110718171338/http://www.lrc.rpi.edu/programs/solidstate/assist/recommends/lightcolor.asp to http://www.lrc.rpi.edu/programs/solidstate/assist/recommends/lightcolor.asp

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== External links modified ==

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*Added archive https://web.archive.org/web/20071012085113/http://www.truesun.com/philips_TL950.php to http://www.truesun.com/philips_TL950.php

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==Suggest merge January 2019==

[[Color rendering capacity]] covers substantially the same subject matter as this article. Any unique material from that article could be merged here to make a more comprehensive discussion. --[[User:Wtshymanski|Wtshymanski]] ([[User talk:Wtshymanski|talk]]) 18:26, 18 January 2019 (UTC)

Support (with caveats) - I agree with the commenters from the previous merge suggestion that CRI is usually use to refer to CIE Ra. I suggest that this page (Colour Rendering Index) be broadened to note this fact but refer to the concept of colour rendering indices more broadly, with CIE Ra obviously forming a large part of that. This would open the door for the inclusion of Gamut Area Indices, the Colour Quality Scale, Memory Colour Indices and most importantly (considering its recent rise to prominance IES TM-30-15/18).[[User:Da5nsy|Da5nsy]] ([[User talk:Da5nsy|talk]]) 19:10, 23 August 2019 (UTC)

===Oppose merge proposal===

"color rendering capacity" is not documented in any color vision or colorimetric text known to me. search results show three hits for the term: this wiki page, the original 1983 paper by xu he, and an unsigned and unsourced web page whose neologisms suggest a chinese author.

the main problem is that color space is not a volume; its dimensions are incommensurate and its space is not euclidean; for example, the chromaticity area implied by hue differences is roughly twice the area implied by chroma differences. there is no standard way to "count the colors" within a chromaticity plane, and illuminance, not illuminant (assuming the light is broadband), is the main source of colorfulness and lightness contrast in surface colors. (the phrase "one unit luminous flux" is incoherent jargon, and if the intended meaning is one lumen then the color measurement is being done by candlelight.) finally, "color rendering capacity" is indistinguishable from "gamut", already widely established as the *limits* of a color space (which are determinate) rather than its indeterminate *volume*, and algorithms to compare gamuts are in wide use and have many practical applications.

rather than merge, i propose that the "color rendering capacity" page be deleted, as i suspect it is self promotional. no other wiki pages link to it. [[User:Drollere|Drollere]] ([[User talk:Drollere|talk]]) 19:20, 12 February 2020 (UTC)

:{{ping|Wtshymanski|Da5nsy|Drollere}} Given this, I've launched a deletion discussion; feel free to contribute at [[Wikipedia:Articles for deletion/Color rendering capacity (2nd nomination)]]. [[User:Klbrain|Klbrain]] ([[User talk:Klbrain|talk]]) 15:06, 12 April 2020 (UTC)

== Request: Add still photo to the "Film and video high-CRI LED lighting incompatibility" section. ==

The "Film and video high-CRI LED lighting incompatibility" section describes the applicability of CRI scores to film and video results. Still digital photography is not specifically mentioned. Could such material be added? <!-- Template:Unsigned --><small class="autosigned">—&nbsp;Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[User:Dmk5717|Dmk5717]] ([[User talk:Dmk5717#top|talk]] • [[Special:Contributions/Dmk5717|contribs]]) 17:52, 3 June 2019 (UTC)</small> <!--Autosigned by SineBot-->