{"id":4324,"date":"2025-01-21T13:08:14","date_gmt":"2025-01-21T18:08:14","guid":{"rendered":"https:\/\/designinglight.com\/?p=4324"},"modified":"2025-01-21T13:08:14","modified_gmt":"2025-01-21T18:08:14","slug":"cie-recommends-transition-from-cri-to-rf","status":"publish","type":"post","link":"https:\/\/designinglight.com\/?p=4324","title":{"rendered":"CIE Recommends Transition from CRI to Rf"},"content":{"rendered":"

Earlier this month, CIE published CIE Position Statement on Color Quality Metrics<\/em><\/a>, in which it recommends the lighting industry transition from the outdated and sometimes inaccurate General Color Rendering Index (CRI) to the General Color Fidelity Index (R<\/em>f <\/sub>) defined in CIE 224:2017. \u00a0The position statement notes that problems with CRI (which we’ve known about for years) include use of an outdated color space (CIE 1960 (u, v<\/em>)), the small number of samples used to calculate CRI (only 8), and that CRI has proven to be especially problematic in evaluating narrow band emitters.<\/p>\n

The good news is that CIE is finally recommending retiring CRI from use (which was last updated over 50 years ago in 1974) and adopting a modern, accurate metric for evaluating fidelity for all lighting applications. \u00a0That’s a huge step forward for the lighting industry.<\/p>\n

The less good news is that it stops there. The position statement acknowledges that fidelity is not the only aspect of color rendering, and that studies have shown preferences for light sources that slightly enhance saturation (and therefore reduce fidelity). \u00a0However, it makes no mention of other metrics (such as ANSI\/IES TM-30’s Gamut Index and Preference Design Intent) that address the issue. \u00a0Since CIE 227’s R<\/em>f<\/sub> and TM-30’s R<\/em>f<\/sub> are identical, I see this as a belated endorsement of R<\/em>f<\/sub> as a fidelity metric and of TM-30 in general. \u00a0My hope is that this spurs the industry to greater adoption of TM-30, especially for its evaluation of color preference, vividness, and fidelity described in Annex E.<\/p>\n

One side note: R<\/em>f<\/sub> as defined in CIE 227 is<\/span> R<\/em>f<\/sub> as defined in TM-30. \u00a0In fact, TM-30 was published two years before CIE 227, which was a response to TM-30. \u00a0In evaluating TM-30, CIE found that there were a few places where CIE and IES chose different methods of extrapolating certain information. \u00a0Since CIE had formalized their procedures and IES had not, the two organizations worked together to harmonize their calculations into one calculation that is used in both systems. \u00a0It’s frustrating that the CIE position statement reads as if CIE developed R<\/em>f<\/sub> out of whole cloth, rather than as a response to TM-30 and a mutual refinement of the R<\/em>f<\/sub> calculation.<\/p>\n","protected":false},"excerpt":{"rendered":"

Earlier this month, CIE published CIE Position Statement on Color Quality Metrics, in which it recommends the lighting industry transition from the outdated and sometimes inaccurate General Color Rendering Index (CRI) to the General Color Fidelity Index (Rf ) defined in CIE 224:2017. \u00a0The position statement notes that problems with CRI (which we’ve known about … Continue reading CIE Recommends Transition from CRI to Rf<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_feature_clip_id":0,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2},"jetpack_post_was_ever_published":false},"categories":[12,11,19],"tags":[27,72,26,68],"class_list":["post-4324","post","type-post","status-publish","format-standard","hentry","category-color","category-leds","category-lighting-profession","tag-color-rendering","tag-color-science","tag-cri","tag-tm-30"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_shortlink":"https:\/\/wp.me\/p4gZSw-17K","jetpack_sharing_enabled":true,"jetpack_likes_enabled":true,"jetpack-related-posts":[{"id":526,"url":"https:\/\/designinglight.com\/?p=526","url_meta":{"origin":4324,"position":0},"title":"CRI Inches Forward","author":"Jason Livingston","date":"November 1, 2015","format":false,"excerpt":"The CIE\u2019s Color Rendition Index (CRI) has long had several known weaknesses including outdated components of the calculations, a limited set of color samples, and standard reporting of only one piece of data (the average color distortion of the first eight colors, known as the General Color Rendering Index or\u2026","rel":"","context":"In "Color"","block_context":{"text":"Color","link":"https:\/\/designinglight.com\/?cat=12"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":2447,"url":"https:\/\/designinglight.com\/?p=2447","url_meta":{"origin":4324,"position":1},"title":"Manufacturers Don’t Understand Color Rendering","author":"Jason Livingston","date":"March 17, 2022","format":false,"excerpt":"I attended LEDucation in New York City this week. \u00a0While there I spoke to over two dozen manufacturers, none of whom understood color rendering beyond the (partially accurate) belief that higher CRI is better. \u00a0My conversations when like this. Lighting Salesperson: \"Our color rendering is great. \u00a0Our CRI is over\u2026","rel":"","context":"In "Color"","block_context":{"text":"Color","link":"https:\/\/designinglight.com\/?cat=12"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":719,"url":"https:\/\/designinglight.com\/?p=719","url_meta":{"origin":4324,"position":2},"title":"CIE Adopts TM-30 (sort of)","author":"Jason Livingston","date":"May 3, 2017","format":false,"excerpt":"The CIE has issued a statement titled \"CIE 2017 Colour Fidelity Index for accurate scientific use\" in which they partially adopt the Rf fidelity metric of TM-30. \u00a0Here are some of the details. When the IES released TM-30-15 it seemed to be a wake up call for the CIE, who\u2026","rel":"","context":"In "Color"","block_context":{"text":"Color","link":"https:\/\/designinglight.com\/?cat=12"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":5394,"url":"https:\/\/designinglight.com\/?p=5394","url_meta":{"origin":4324,"position":3},"title":"A Brief History of TM-30","author":"Jason Livingston","date":"April 9, 2026","format":false,"excerpt":"Next Wednesday I\u2019ll be giving a presentation on LP-30 at LEDucation (hope to see you there!), and in preparing for it I\u2019ve been reflecting on how far we\u2019ve come in our understanding and evaluation of color rendering. \u00a0 The Color Rendering Index (CRI) was published by the International Commission on\u2026","rel":"","context":"In "Color"","block_context":{"text":"Color","link":"https:\/\/designinglight.com\/?cat=12"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":780,"url":"https:\/\/designinglight.com\/?p=780","url_meta":{"origin":4324,"position":4},"title":"The Advantages of TM-30","author":"Jason Livingston","date":"October 30, 2017","format":false,"excerpt":"In this series of posts about IES TM-30-15 I've discussed the problems with CRI and the resistance to adopting TM-30. \u00a0In this post I'll discuss the advantages of TM-30 over CRI, and what TM-30 is and isn't. Color Samples Like CRI, TM-30 compares color samples rendered by a given test\u2026","rel":"","context":"In "Color"","block_context":{"text":"Color","link":"https:\/\/designinglight.com\/?cat=12"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/designinglight.com\/wp-content\/uploads\/2017\/10\/TM-30-Bins.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/designinglight.com\/wp-content\/uploads\/2017\/10\/TM-30-Bins.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/designinglight.com\/wp-content\/uploads\/2017\/10\/TM-30-Bins.jpg?resize=525%2C300&ssl=1 1.5x"},"classes":[]},{"id":386,"url":"https:\/\/designinglight.com\/?p=386","url_meta":{"origin":4324,"position":5},"title":"A New Color Rendering Metric","author":"Jason Livingston","date":"May 11, 2015","format":false,"excerpt":"At last week\u2019s Lightfair one of the presentations was Quantifying Color Rendition: A Path Forward. The presentation was the first public look at the (not yet approved) IES Method of quantifying color rendering. What is this new (not yet approved) IES Method? Let\u2019s start with a quick review of the\u2026","rel":"","context":"In "Color"","block_context":{"text":"Color","link":"https:\/\/designinglight.com\/?cat=12"},"img":{"alt_text":"CRI Test Color Sample SPDs","src":"https:\/\/i0.wp.com\/designinglight.com\/wp-content\/uploads\/2015\/05\/CIE_CRI_TCS_SPDs.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/designinglight.com\/wp-content\/uploads\/2015\/05\/CIE_CRI_TCS_SPDs.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/designinglight.com\/wp-content\/uploads\/2015\/05\/CIE_CRI_TCS_SPDs.jpg?resize=525%2C300&ssl=1 1.5x"},"classes":[]}],"_links":{"self":[{"href":"https:\/\/designinglight.com\/index.php?rest_route=\/wp\/v2\/posts\/4324","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/designinglight.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/designinglight.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/designinglight.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/designinglight.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=4324"}],"version-history":[{"count":1,"href":"https:\/\/designinglight.com\/index.php?rest_route=\/wp\/v2\/posts\/4324\/revisions"}],"predecessor-version":[{"id":4325,"href":"https:\/\/designinglight.com\/index.php?rest_route=\/wp\/v2\/posts\/4324\/revisions\/4325"}],"wp:attachment":[{"href":"https:\/\/designinglight.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=4324"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/designinglight.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=4324"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/designinglight.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=4324"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}