{"id":5532,"date":"2026-07-13T09:00:08","date_gmt":"2026-07-13T13:00:08","guid":{"rendered":"https:\/\/designinglight.com\/?p=5532"},"modified":"2026-07-09T15:22:36","modified_gmt":"2026-07-09T19:22:36","slug":"cri-has-one-job-thats-the-problem","status":"publish","type":"post","link":"https:\/\/designinglight.com\/?p=5532","title":{"rendered":"CRI Has One Job. That\u2019s the Problem."},"content":{"rendered":"

Below is a slightly expanded version of an article I wrote for this month’s IES NYC newsletter.<\/em><\/p>\n

Color rendering should be an intentional design decision, not a specification checkbox. \u00a0I was recently in what should have been a beautiful hotel bar.\u00a0 The interior was relatively new and skillfully conceived and executed, the materials were luxurious, and the lighting design should have been beautiful. Unfortunately, the overall look of the space was flat and dull.\u00a0 It didn\u2019t take me long to figure out why \u2013 poor color rendering was muting the colors in the space.<\/p>\n

I could tell that the SPD, while warm (roughly 2400 K) was still deficient in red and probably had a CRI in the low 80s.\u00a0 The lighting designer probably relied on CRI, which isn\u2019t up to the job in this application. \u00a0CRI only tells you one thing about a light source: fidelity, or how closely it matches the reference light source. \u00a0This means the designer can have only one color rendering goal. \u00a0TM-30, on the other hand, supports a broad range of possibly overlapping color rendering goals. \u00a0The lighting designer then balances the metrics, evaluating of preference, vividness, and fidelity to achieve specific goals.<\/p>\n

Start with Blue to Make Red<\/h3>\n

Most of us know that white light LEDs start with a blue LED as the “pump”. \u00a0Phosphors packed on top of the blue LED convert a large portion of that blue light to longer wavelengths. \u00a0Converting high energy, short wavelength blue light to lower energy, longer wavelength light comes at the expense of efficacy. \u00a0The more blue light converted to green, yellow, orange, and red, the lower the LED’s lumens per watt. \u00a0Since most manufacturers prize efficacy over color rendering, the skimp on red compared to the reference light source, resulting in low CRI.<\/p>\n

Figure 1 is a TM-30 report for a typical 80 CRI LED. \u00a0At the top right hand corner the P3 V- F- means its color rendering meets Priority Level 3 for Color Preference (P3) so it is slightly preferred over a high CRI source, that it doesn\u2019t increase the vividness of colors (V-), and that the color rendering is not very close to its reference source (F-).\u00a0 In the graphic, the red arrows pointing toward the center of the circle indicate less energy in those color ranges than in the reference source.\u00a0 This results in the muting or graying of all object colors in those ranges, including the skin of the people in the room.<\/p>\n

\"TM-30
Figure 1 – TM-30 report of a typical 80 CRI light source.<\/figcaption><\/figure>\n

 <\/p>\n

Figure 2 is a TM-30 Simple Report of a typical 90 CRI LED.\u00a0 Even here, there\u2019s slightly less red than in the reference light source. P2 indicates that it is broadly preferred over a high CRI source and F2 indicates that it has good color fidelity.<\/p>\n

 <\/p>\n

\"TM-30
Figure 2 – TM-30 report of a typical 90 CRI light source<\/figcaption><\/figure>\n

 <\/p>\n

Use the Tools<\/h3>\n

So, using a 90 CRI LED instead of an 80 CRI LED would improve things, and many designers and manufacturers are defaulting to 90 CRI these days.\u00a0 However, there\u2019s another problem \u2013 the Hunt effect, which tells us that as illuminance decreases, so does perceived object colorfulness.\u00a0 The bar was lit to somewhere between 5 and 10 fc, so even under a high CRI source the colors in the room would be muted compared to their appearance at, say, 50 fc.\u00a0 CRI leaves us powerless to do anything about this, but TM-30 gives us the tools.<\/p>\n

Instead of looking for a high CRI source, the designer could have used the PVF measures from TM-30 to find a high preference source, as shown in Figure 3.\u00a0 A light source that measures P1 (highly<\/em> preferred compared to the reference source) has a spectrum that increases red saturation, which would enhance the colors of materials in a way that people prefer over high fidelity – and possibly somewhat negate the Hunt effect.<\/p>\n

 <\/p>\n

\"TM-30
Figure 3 – TM-30 report for a typical high preference light source<\/figcaption><\/figure>\n

 <\/p>\n

When attempting to counter the Hunt effect, a light source that also increases the overall vividness of colors (V3 or V2) would do an even better job. \u00a0This is just one example of how switching to TM-30 and broadening your color rendering goals can enhance your lighting designs.<\/p>\n

Don’t Trade One-for-One<\/h3>\n

One final note.\u00a0 In January of 2025 the CIE recommended<\/a> the lighting industry transition from CRI to R<\/em>f<\/sub>, which is a much more accurate measure of fidelity.\u00a0 My position, and that of the IES Color Committee, is it makes no sense to swap out one fidelity measure for another. \u00a0Designers would still be limited to a single color rendering goal. \u00a0We\u2019d like the industry to adopt the full TM-30 suite. \u00a0Designers can ignore the 149 calculated values and focus on the PVF categories as I’ve done here.<\/p>\n

For a full explanation of the color rendering goals possible with TM-30 and Preference, Vividness, and Fidelity, see ANSI\/IES LP-30 Lighting Practice: A Comprehensive Guide to Specifying Color Rendition – Concepts, Criteria, and Implementation <\/em>in the IES Online Store or the Online Lighting Library.\u00a0 Despite its long title it is an easy to read, phase-by-phase user\u2019s guide to TM-30. From schematic design to construction documentation, this TM-30 user’s guide outlines important color quality considerations and how to incorporate them into your workflow.<\/p>\n","protected":false},"excerpt":{"rendered":"

Below is a slightly expanded version of an article I wrote for this month’s IES NYC newsletter. Color rendering should be an intentional design decision, not a specification checkbox. \u00a0I was recently in what should have been a beautiful hotel bar.\u00a0 The interior was relatively new and skillfully conceived and executed, the materials were luxurious, … Continue reading CRI Has One Job. That\u2019s the Problem.<\/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":[12,17,19],"tags":[27,26,68],"class_list":["post-5532","post","type-post","status-publish","format-standard","hentry","category-color","category-light","category-lighting-profession","tag-color-rendering","tag-cri","tag-tm-30"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_shortlink":"https:\/\/wp.me\/p4gZSw-1re","jetpack_sharing_enabled":true,"jetpack_likes_enabled":true,"jetpack-related-posts":[{"id":954,"url":"https:\/\/designinglight.com\/?p=954","url_meta":{"origin":5532,"position":0},"title":"Misunderstanding CRI","author":"Jason Livingston","date":"April 8, 2019","format":false,"excerpt":"Discusses a common misuse of CRI and how it is corrected with TM-30.","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\/2019\/04\/LED90.png?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/designinglight.com\/wp-content\/uploads\/2019\/04\/LED90.png?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/designinglight.com\/wp-content\/uploads\/2019\/04\/LED90.png?resize=525%2C300&ssl=1 1.5x"},"classes":[]},{"id":4324,"url":"https:\/\/designinglight.com\/?p=4324","url_meta":{"origin":5532,"position":1},"title":"CIE Recommends Transition from CRI to Rf","author":"Jason Livingston","date":"January 21, 2025","format":false,"excerpt":"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\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":5532,"position":2},"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":3148,"url":"https:\/\/designinglight.com\/?p=3148","url_meta":{"origin":5532,"position":3},"title":"AI and the Internet Need to Learn Color Rendering","author":"Jason Livingston","date":"March 28, 2023","format":false,"excerpt":"Recently a colleague of mine from the IES Color Committee asked of one of the new AIs \"Tell me about color rendering.\" \u00a0If we assume that the answer was formulated based on information about color rendering that is available on the internet we have a problem because the answer the\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":769,"url":"https:\/\/designinglight.com\/?p=769","url_meta":{"origin":5532,"position":4},"title":"R.I.P. CRI","author":"Jason Livingston","date":"October 16, 2017","format":false,"excerpt":"It's been a little over two years since the IES released TM-30-15 IES Method for Evaluating Light Source Color Rendition. \u00a0In that time TM-30 has seen growing support in the industry and a growing body of evidence for its accuracy and usefulness. \u00a0We've nearly reached the moment when we can\u2026","rel":"","context":"In "Calculations"","block_context":{"text":"Calculations","link":"https:\/\/designinglight.com\/?cat=6"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":5394,"url":"https:\/\/designinglight.com\/?p=5394","url_meta":{"origin":5532,"position":5},"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":[]}],"_links":{"self":[{"href":"https:\/\/designinglight.com\/index.php?rest_route=\/wp\/v2\/posts\/5532","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=5532"}],"version-history":[{"count":5,"href":"https:\/\/designinglight.com\/index.php?rest_route=\/wp\/v2\/posts\/5532\/revisions"}],"predecessor-version":[{"id":5612,"href":"https:\/\/designinglight.com\/index.php?rest_route=\/wp\/v2\/posts\/5532\/revisions\/5612"}],"wp:attachment":[{"href":"https:\/\/designinglight.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=5532"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/designinglight.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=5532"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/designinglight.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=5532"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}