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 AI returned was almost completely wrong. \u00a0That strongly suggests that most individuals and manufacturers posting information about color rendering don’t fully understand color rendering and are perpetuating outdated or incorrect information. \u00a0Here’s what the AI had to say, and what’s wrong with it’s response.<\/p>\n
Color rendering is a measure of how well a light source reveals the true colors of objects. (1)<\/strong> A light source with a high CRI (Color Rendering Index) will show objects in their natural colors (2)<\/strong>, while a light source with a low CRI will make objects look dull or washed out (3)<\/strong>. \u00a0The CRI is a scale from 0 to 100 (4)<\/strong>, with 100 being the perfect score (5)<\/strong>. \u00a0A light source with a CRI of 100 will show objects in their true colors (1)<\/strong> while a light source with a CRI if 0 will make all objects look the same color (6)<\/strong>.<\/p>\nThe CRI (7)<\/strong> is important for applications where it is important to see objects in their true colors (1)<\/strong>, such as art galleries, hospitals, and retail stores (8)<\/strong>. \u00a0It is also important for applications where it is important to see subtle variations in color such as fashion design and photography (9)<\/strong>.<\/p>\nThere are a few things that can affect the CRI of a light source (10)<\/strong>. \u00a0The type of light source (incandescent, fluorescent, LED, etc.) will affect the CRI (11)<\/strong>. \u00a0The color temperature of the light source will also affect the CRI (12)<\/strong>. \u00a0Light sources with a higher color temperature will have a higher CRI (12)<\/strong>.<\/p>\nThe CRI (7)<\/strong> is a valuable tool for choosing the right light source for your application. \u00a0By understanding the CRI, you can choose a light source that will show your objects in their true colors (1)<\/strong> and help you achiever the desired look and feel for your space.<\/p>\n
\n<\/blockquote>\n\n- Objects don’t have “true” colors, they have apparent colors. \u00a0The color of an object is determined by the spectrum of light striking it, it’s reflective properties, and the resulting light directed toward the observer. \u00a0An object’s reflective properties don’t change, but the spectrum of light changes every time the light source changes. \u00a0Changing the spectrum may, therefore, change the color appearance of the object, hence apparent color.<\/li>\n
- While there is a correlation between fidelity and naturalness, they are not the same thing. \u00a0CRI measures fidelity, i.e. how well a given light source matches the color rendering of a defined reference light source.<\/li>\n
- One of the problems with single measure metrics like CRI is that there’s a lot of information that isn’t conveyed. \u00a0As CRI values drop, the only thing conveyed is that the match to the reference light source is worse. \u00a0A worse match, however, doesn’t mean colors are made dull. It could be they are increased in saturation since both deviations from the reference are equally penalized. \u00a0That’s the advantage of TM-30. \u00a0As Rf decreases we can see why by looking at Rg and some of the other 147 measures.<\/li>\n
- CRI can have negative values. \u00a0TM-30 Rf is calculated so that 0 is the lowest value.<\/li>\n
- 100 is the highest value. \u00a0It’s dangerous to call it “perfect” though as that implies that high fidelity is the only color rendering goal, which it isn’t. \u00a0TM-30 provides information for the color rendering goals of preference and vividness, and may include more in the future.<\/li>\n
- A CRI of 0 will certainly make nearly all colors look terrible and very similar, but not all the same.<\/li>\n
- CRI isn’t a proper noun, and shouldn’t be preceded by “the”.<\/li>\n
- There are strong arguments for emphasizing preference over fidelity in many applications, including retail. \u00a0Again, fidelity isn’t the only color rendering goal, although it is the only one CRI measures.<\/li>\n
- Research shows that high fidelity isn’t necessarily the best spectrum for detecting color difference. \u00a0Additional research is needed, but the IES may eventually add a color difference metric to TM-30.<\/li>\n
- Only one thing affects CRI value – the spectrum of the light source.<\/li>\n
- This is true because different light producing technologies have similar quirks in their spectra. \u00a0Those similarities can lead us to blanket statements such as “all fluorescents are green” which are not true for all products. \u00a0Again, the individual light source’s spectrum determines everything.<\/li>\n
- A common misconception, but not true at all. \u00a0Not in the slightest. CCT and CRI are separate metrics.<\/li>\n<\/ol>\n","protected":false},"excerpt":{"rendered":"
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 AI returned was almost completely … Continue reading AI and the Internet Need to Learn Color Rendering<\/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":[12,18,21,17,19],"tags":[61,27,72,29,26,68],"class_list":["post-3148","post","type-post","status-publish","format-standard","hentry","category-color","category-design","category-education","category-light","category-lighting-profession","tag-color-perception","tag-color-rendering","tag-color-science","tag-color-temperature","tag-cri","tag-tm-30"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_shortlink":"https:\/\/wp.me\/p4gZSw-OM","jetpack_sharing_enabled":true,"jetpack_likes_enabled":true,"jetpack-related-posts":[{"id":954,"url":"https:\/\/designinglight.com\/?p=954","url_meta":{"origin":3148,"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":386,"url":"https:\/\/designinglight.com\/?p=386","url_meta":{"origin":3148,"position":1},"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":[]},{"id":92,"url":"https:\/\/designinglight.com\/?p=92","url_meta":{"origin":3148,"position":2},"title":"The Best Light?","author":"Jason Livingston","date":"January 31, 2014","format":false,"excerpt":"In class yesterday one of my students, thinking about a project she had recently completed, asked, \"What's the best light for a hair salon?\" \u00a0I'm certain she was hoping I would tell her exactly what lamp technology and\/or lamp style to use. \u00a0Of course, it's not that simple. So 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":5532,"url":"https:\/\/designinglight.com\/?p=5532","url_meta":{"origin":3148,"position":3},"title":"CRI Has One Job. That\u2019s the Problem.","author":"Jason Livingston","date":"July 13, 2026","format":false,"excerpt":"Below is a slightly expanded version of an article I wrote for this month's IES NYC newsletter. 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