(favicon.png@v1)  (favicon.svg@v1) (favicon.ico@v1)  (https://gizmodo.com/apple-touch-icon.png?v1) (site.webmanifest) (https://gizmodo.com/safari-pinned-tab.svg?v1) (../cdnjs.cloudflare.com/ajax/libs/font-awesome/5.15.3/css/all.min.css)  This NASA Color Trick Was Meant for Mars. Now It's Unveiling Rock Art on Earth  (this-nasa-color-trick-was-meant-for-mars-now-its-unveiling-rock-art-on-earth-2000809844.html)                        (https://api.consentframework.com/)  (https://cache.consentframework.com/)  (https://scripts.opti-digital.com/)  (https://gizmodo.com/feed)      (https://securepubads.g.doubleclick.net/tag/js/gpt.js)  (app/plugins/pdfjs-viewer-shortcode/blocks/dist/style.css@ver=2.2.1.css) (app/plugins/keleops-liveblog/css/liveblog.min.css@ver=0.6.0.css) (app/plugins/keleops-shopbot/css/all.min.css@ver=1.6.37.css) (app/plugins/keleops-toc/assets/css/screen.min.css@ver=2.0.23.css) (app/themes/gizmodo/public/app.43e1e3.css)    (this-nasa-color-trick-was-meant-for-mars-now-its-unveiling-rock-art-on-earth-2000809844.html#main) Skip to content   (https://gizmodo.com)     Gizmodo   (https://gizmodo.com/latest) Latest  (https://gizmodo.com/tech) News  (https://gizmodo.com/reviews) Reviews  (https://gizmodo.com/io9) io9  (https://gizmodo.com/science) Science  (https://gizmodo.com/deals) Deals  (https://gizmodo.com/download/) Downloads   (https://gizmodo.com/search) (Search)     (https://gizmodo.com/newsletters) Newsletters   (Switch Color Scheme)    (Menu)               (https://gizmodo.com/science/human-history) Human History   This NASA Color Trick Was Meant for Mars. Now It’s Unveiling Rock Art on Earth  Rather than simply raising the contrast between colors, the decorrelation method maps the original colors to an expanded range.   By  (https://gizmodo.com/author/prabie) Passant Rabie    Published September 10, 2026, 10:50 am ET   Reading time 3 minutes   (Harman poses in front of an example of the Rancho Bernardo style of Native American artwork.)  Harman poses in front of an example of the Rancho Bernardo style of Native American artwork. Jon Harman         Read Later    Read Later   (this-nasa-color-trick-was-meant-for-mars-now-its-unveiling-rock-art-on-earth-2000809844.html#comments)   Comments (5)    In 2005, archaeologist Jon Harman was attending a conference on rock art when he came across an unexpected source of inspiration: images of Mars. One showed the planet’s familiar rusty-red surface; another, created using a method developed at NASA, transformed the Martian landscape into a striking mosaic of red, green, and yellow, revealing remarkable detail. Harman immediately saw how the technique could help researchers study some of the world’s oldest paintings.  (Dstretch 2ab.jpg)  The image of the Martian surface, with and without the decorrelation stretch technique applied. Credit: NASA  The technique, known as decorrelation stretch, is used to enhance contrasts in digital imagery. It was first developed by researchers at NASA’s Jet Propulsion Laboratory (JPL) in 1978 to improve the interpretation of high-correlation remote sensing and satellite imagery. “I Googled it and found a NASA paper that explained how to do the algorithm,” Harman said in a (https://www.nasa.gov/technology/tech-transfer-spinoffs/nasa-technique-for-manipulating-satellite-photos-now-reveals-ancient-images/) statement . The archeologist first applied it to photos he had taken of rock art in Baja California, Mexico, revealing a new yellow figure in one image that seemed to appear out of nowhere. “That convinced me of the usefulness,” he said.    (Dstretch 3ab Side By Side.jpg)  The yellow figure appeared in this image from the Cave of San Borjitas in Baja California, Mexico. Credit: Harman  Since then, Harman has used a software plug-in to enhance hundreds of images of ancient rock art. Space technology on Earth Rather than simply raising the contrast between colors, decorrelation stretch maps the original colors to a different, expanded range of colors. The technique is based on the Karhunen–Loève Transform, a theorem used in statistical analysis to maximize energy compaction (i.e., concentrating most of a signal’s information into fewer components).    In 1978, a supervisor of a digital image processing group at JPL, Jim Soha, proposed applying the Karhunen–Loève Transform to digital imagery for color enhancement. Later in 1996, Ronald Alley, who was a member of Soha’s group at JPL, refined the process to make it faster and more accurate. It was Alley’s (https://www.semanticscholar.org/paper/Algorithm-Theoretical-Basis-Document-for%3A-Stretch-Alley/0a2429954225929702894cc035c3d22a154e2548) paper that Harman stumbled upon when he first began his own journey in adopting the technique to study rock art. “Someone had to write up a description of this thing so users would know what we were talking about,” Alley said in a statement.    Harman, who is now retired in Pacifica, California, has experience in medical imaging, in addition to a PhD in math from Berkeley, which gave him confidence he could figure it out. Using Alley’s paper, Harman created the Dstretch software plug-in to enhance digital imagery. Uncovering the past The archeologist was able to tailor the decorrelation stretch method to rock art. “I started playing around and found that by changing the color space I was working in, I could get good results in different images,” he said. A color space is a range of numerically represented colors, such as the RGB color space (red-green-blue) commonly used on screen devices. The Dstretch plug-in includes custom color spaces that have proven useful with Harman’s images of rock art.    (Stone Wall)  Singaporean archaeologist Noel Hidalgo Tan used the Dstretch plug-in to discover more than 200 faded paintings around the Angkor Wat temple complex in Cambodia. Credit: Noel Hidalgo Tan  Archaeologists have used Dstretch to discover images of bats and pigs in the ancient Egyptian cemetery of Beni Hassan, revealing animals rarely depicted in ancient Egyptian art. In Alberta, Canada’s Writing-on-Stone Provincial Park, Dstretch revealed what could be considered an early form of graffiti tagging: a pictograph of a horse and rider that is believed to serve as a calling card from a Crow warrior, taunting his Blackfoot enemies. The plug-in software also uncovered about 15 previously undocumented figures and revealed new details in 28 others at the Årsand 1 site in western Norway. “No one really knows why people made the rock art they made, at least in many cases,” Harman said of his fascination with the ancient paintings. “And the symbols are quite strange.”     Explore more on these topics (https://gizmodo.com/tag/nasa) NASA  (https://gizmodo.com/tag/satellites) satellites     Share this story  (https://www.facebook.com/sharer.php?display=popup&u=https%3A%2F%2Fgizmodo.com%2Fthis-nasa-color-trick-was-meant-for-mars-now-its-unveiling-rock-art-on-earth-2000809844%3Futm_source%3Dfacebook%26utm_medium%3Dsocial%26utm_campaign%3Dshare) (Share on Facebook)    (https://threads.net/intent/post?text=This%20NASA%20Color%20Trick%20Was%20Meant%20for%20Mars.%20Now%20It%E2%80%99s%20Unveiling%20Rock%20Art%20on%20Earth&url=https%3A%2F%2Fgizmodo.com%2Fthis-nasa-color-trick-was-meant-for-mars-now-its-unveiling-rock-art-on-earth-2000809844%3Futm_source%3Dthreads%26utm_medium%3Dsocial%26utm_campaign%3Dshare) (Share on Threads)    (Share on X (Twitter))    (https://www.reddit.com/submit?url=https%3A%2F%2Fgizmodo.com%2Fthis-nasa-color-trick-was-meant-for-mars-now-its-unveiling-rock-art-on-earth-2000809844%3Futm_source%3Dreddit%26utm_medium%3Dsocial%26utm_campaign%3Dshare&title=This%20NASA%20Color%20Trick%20Was%20Meant%20for%20Mars.%20Now%20It%E2%80%99s%20Unveiling%20Rock%20Art%20on%20Earth&type=link) (Share on Reddit)    (https://gizmodo.com/this-nasa-color-trick-was-meant-for-mars-now-its-unveiling-rock-art-on-earth-2000809844?utm_source=gizmodo.com&utm_medium=link&utm_campaign=share) (Copy link)   Copied!     Sign up for our newsletters Subscribe and interact with our community, get up to date with our customised Newsletters and much more.   Gizmodo (df9387f21b)   io9 (219e86e11b)   Earther (5beca34192)   The Next Interface (74d082c487)    (EMAIL ADDRESS) Subscribe now    Leave this field empty if you're human: ()   (1789077073)  (2000506218)  (mc4wp-form-1)           (https://gizmodo.com/back-to-school-the-best-ways-to-get-around-campus-2000802419) Back to School: All the Accessories You Need to Replace Your Laptop With a Foldable Phone  (https://gizmodo.com/back-to-school-all-the-accessories-you-need-to-replace-your-laptop-with-a-foldable-phone-2000806487) (Back to School: All the Accessories You Need to Replace Your Laptop With a Foldable Phone)               Latest news    (https://gizmodo.com/heres-palantir-ceo-alex-karp-wearing-a-keffiyeh-in-college-2000810168)    Sep 10 5:25 pm  Here’s Palantir CEO Alex Karp Wearing a Keffiyeh in College     (https://gizmodo.com/the-record-labels-are-done-fighting-ai-now-they-want-a-cut-2000809977)        Sep 10 5:10 pm  The Record Labels Are Done Fighting AI. Now They Want a Cut     (https://gizmodo.com/apples-biggest-ai-advantage-its-not-trying-to-build-god-2000809978)      Sep 10 4:40 pm  Apple’s Biggest AI Advantage: It’s Not Trying to Build God     (https://gizmodo.com/scientists-tried-recreating-uranian-and-neptunian-ice-heres-what-happened-2000810092)      Sep 10 4:30 pm  Scientists Tried Recreating Uranian and Neptunian Ice. Here’s What Happened     (https://gizmodo.com/live-updates-from-apples-surprise-and-shine-iphone-event-2000806403)      Sep 10 4:18 pm  Live Updates From Apple’s ‘Surprise and Shine’ iPhone Event 🔴     (https://gizmodo.com/widows-bay-gets-a-vinyl-release-thats-as-fun-and-creepy-as-the-show-itself-2000810077)      Sep 10 4:15 pm  ‘Widow’s Bay’ Gets a Vinyl Release That’s as Fun and Creepy as the Show Itself     (https://gizmodo.com/scientists-confirmed-a-new-us-mosquito-species-and-it-may-already-be-spreading-2000809965)      Sep 10 3:50 pm  Scientists Confirmed a New US Mosquito Species—and It May Already Be Spreading     (https://gizmodo.com/the-far-right-pivots-to-hating-algorithmic-immigrants-2000809942)      Sep 10 3:28 pm  The Far-Right Pivots to Hating ‘Algorithmic Immigrants’       (https://gizmodo.com/latest) Show All Latest news                  Latest Reviews    (https://gizmodo.com/back-to-school-all-the-accessories-you-need-to-replace-your-laptop-with-a-foldable-phone-2000806487)    Sep 8 12:45 pm  Back to School: All the Accessories You Need to Replace Your Laptop With a Foldable Phone     (https://gizmodo.com/sony-wh-ch530-review-cheap-wireless-headphones-2000807005)        Sep 7 12:00 pm  Sony’s New $70 Wireless Headphones Have Me Rethinking Everything     (https://gizmodo.com/lg-gram-pro-16-inch-2026-review-an-expensive-disappointment-2000805940)      Sep 6 8:30 am  LG Gram Pro 16-Inch (2026) Review: An Expensive Disappointment     (https://gizmodo.com/gizmodos-best-of-ifa-2026-awards-see-the-winners-2000800027)      Sep 5 5:45 pm  Gizmodo’s Best of IFA 2026 Awards: See the Winners     (https://gizmodo.com/best-gaming-budget-work-laptop-macbook-razer-dell-hp-1849814722)      Sep 1 2:20 pm  The Best Laptops of 2026     (https://gizmodo.com/back-to-school-the-best-ways-to-get-around-campus-2000802419)      Sep 1 8:30 am  Back to School: The Best Ways to Get Around Campus     (https://gizmodo.com/best-wireless-earbuds-right-now-1851353120)      Sep 1 3:03 pm  The Best Wireless Earbuds of 2026     (https://gizmodo.com/the-best-gadgets-of-august-2026-2000802363)      Aug 31 8:30 am  The Best Gadgets of August 2026       (https://gizmodo.com/reviews) Show All Latest Reviews                Related Articles  (https://gizmodo.com/back-to-school-all-the-accessories-you-need-to-replace-your-laptop-with-a-foldable-phone-2000806487) (Back to School: All the Accessories You Need to Replace Your Laptop With a Foldable Phone)  (https://gizmodo.com/back-to-school-all-the-accessories-you-need-to-replace-your-laptop-with-a-foldable-phone-2000806487) Back to School: All the Accessories You Need to Replace Your Laptop With a Foldable Phone  Ditch your laptop and go with something more compact for your computing needs.   (https://gizmodo.com/reviews/phones) Smartphones    (https://gizmodo.com/author/raywong) Raymond Wong    (September 8, 2026, 12:45 pm) Sep 8      (https://gizmodo.com/nasa-readies-its-quiet-supersonic-jet-for-a-noise-test-later-this-year-2000808277) (X 59 Flight 24)  (https://gizmodo.com/nasa-readies-its-quiet-supersonic-jet-for-a-noise-test-later-this-year-2000808277) NASA Readies Its Quiet Supersonic Jet for a Noise Test Later This Year  The agency wants to see just how quiet the X-59 really is.   (https://gizmodo.com/science/space) Space & Spaceflight    (https://gizmodo.com/author/prabie) Passant Rabie    (September 7, 2026, 4:25 pm) Sep 7      (https://gizmodo.com/extreme-drought-has-shrivelled-new-mexicos-largest-reservoir-down-to-just-1-4-2000807403) (Elephant Butte Reservoir Drought Nm)  (https://gizmodo.com/extreme-drought-has-shrivelled-new-mexicos-largest-reservoir-down-to-just-1-4-2000807403) Extreme Drought Has Shrivelled New Mexico’s Largest Reservoir Down to Just 1.4%  The scientists managing NASA’s imaging satellites are not only tracking the reservoir’s disappearing water but also assisting drought-ravaged farmers and local communities.   (https://gizmodo.com/earther/climate-change) Climate Change    (https://gizmodo.com/author/matthew-phelan) Matthew Phelan    (September 4, 2026, 10:20 am) Sep 4          (https://gizmodo.com/nasas-pluto-probe-could-lose-2-key-instruments-at-a-crucial-moment-2000806831) (Nasa New Horizons)  (https://gizmodo.com/nasas-pluto-probe-could-lose-2-key-instruments-at-a-crucial-moment-2000806831) NASA’s Pluto Probe Could Lose 2 Key Instruments at a Crucial Moment  The spacecraft is currently approaching the outer boundary of the solar system as it prepares to cross into interstellar space.   (https://gizmodo.com/science/space) Space & Spaceflight    (https://gizmodo.com/author/prabie) Passant Rabie    (September 3, 2026, 12:05 pm) Sep 3      (https://gizmodo.com/trump-repeatedly-tried-to-cancel-the-roman-space-telescope-now-hes-praising-its-launch-2000804954) (President Donald Trump presents an executive order establishing the United States Space Academy during an event to award the Congressional Space Medal of Honor to the Artemis II crew as Michael Kratsios, director of the Office of Science and Technology Policy, left; Kevin Hassett, director of the National Economic Council, third from left; and NASA Administrator Jared Isaacman, right, applaud, Friday, Aug. 28, 2026, at NASA’s Johnson Space Center in Houston.)  (https://gizmodo.com/trump-repeatedly-tried-to-cancel-the-roman-space-telescope-now-hes-praising-its-launch-2000804954) Trump Crashed NASA’s Press Conference to Praise the Space Telescope He Repeatedly Tried to Kill  The president interrupted a NASA press briefing to say, "I'm supplying you all that money."   (https://gizmodo.com/science/space) Space & Spaceflight    (https://gizmodo.com/author/prabie) Passant Rabie    (August 31, 2026, 11:15 am) Aug 31      (https://gizmodo.com/nasa-is-launching-a-4-billion-space-telescope-sunday-heres-why-you-should-care-2000803307) (Roman Telescope)  (https://gizmodo.com/nasa-is-launching-a-4-billion-space-telescope-sunday-heres-why-you-should-care-2000803307) NASA Is Launching a $4 Billion Space Telescope on Sunday. Here’s Why You Should Care  Roman is designed to capture enormous areas of the universe quickly and precisely—and gaze upon things we've never seen before.   (https://gizmodo.com/science/space) Space & Spaceflight    (https://gizmodo.com/author/prabie) Passant Rabie    (August 26, 2026, 1:30 pm) Aug 26               (this-nasa-color-trick-was-meant-for-mars-now-its-unveiling-rock-art-on-earth-2000809844.html#)     (https://gizmodo.com)    ©2026 GIZMODO USA LLC. All rights reserved.  (Facebook) (https://facebook.com/gizmodo)    (Instagram) (https://instagram.com/gizmodo)    (X (Twitter)) (https://x.com/Gizmodo) 𝕏  (LinkedIn) (https://www.linkedin.com/company/gizmodo-usa)    (YouTube) (https://www.youtube.com/gizmodo)    (RSS) (https://gizmodo.com/feed)       (https://gizmodo.com/about) About Us  (this-nasa-color-trick-was-meant-for-mars-now-its-unveiling-rock-art-on-earth-2000809844.html#) Other editions  (https://de.gizmodo.com/) Deutsch  (https://es.gizmodo.com) Español  (https://fr.gizmodo.com) Français  (https://www.gizmodo.com.br) Português    (https://gizmodo.com/jobs) Jobs  (https://gizmodo.com/how-gizmodo-tests-products) Product Review  (https://gizmodo.com/newsletter) Newsletters   (this-nasa-color-trick-was-meant-for-mars-now-its-unveiling-rock-art-on-earth-2000809844.html#) Your Privacy Choices  (https://gizmodo.com/privacy-policy) Privacy Policy  (https://gizmodo.com/terms-of-service) Terms of Use  (https://gizmodo.com/accessibility) Accessibility  (https://gizmodo.com/advertise-with-us) Advertising & Licensing   (Facebook) (https://facebook.com/gizmodo)    (Instagram) (https://instagram.com/gizmodo)    (X (Twitter)) (https://x.com/Gizmodo) 𝕏  (LinkedIn) (https://www.linkedin.com/company/gizmodo-usa)    (YouTube) (https://www.youtube.com/gizmodo)    (RSS) (https://gizmodo.com/feed)         We may earn a commission when you buy through links on our sites.                                                                                                   (https://gizmodo.com/)           Search (Search authors, topics, headlines) ()     (https://gizmodo.com/newsletters) Sign up for our newsletters   (https://gizmodo.com/latest) Latest   (https://gizmodo.com/tech) Tech News   (https://gizmodo.com/tech/artificial-intelligence) Artificial Intelligence    (https://gizmodo.com/tech/commerce) Commerce    (https://gizmodo.com/tech/crime) Crime    (https://gizmodo.com/tech/cryptocurrencies) Cryptocurrencies    (https://gizmodo.com/tech/culture) Culture    (https://gizmodo.com/tech/gadgets) Gadgets    (https://gizmodo.com/tech/internet) Internet    (https://gizmodo.com/tech/politics) Politics    (https://gizmodo.com/tech/privacy-and-security) Privacy & Security    (https://gizmodo.com/tech/robots) Robots    (https://gizmodo.com/tech/social-media) Social Media    (https://gizmodo.com/tech/sploid) Sploid    (https://gizmodo.com/tech/tech-policy) Tech Policy    (https://gizmodo.com/tech/transportation) Transportation      (https://gizmodo.com/reviews) Reviews   (https://gizmodo.com/reviews/phones) Smartphones    (https://gizmodo.com/reviews/laptops) Laptops    (https://gizmodo.com/reviews/headphones) Headphones    (https://gizmodo.com/reviews/gaming) Gaming    (https://gizmodo.com/reviews/home-entertainment) Home Entertainment & Smart Home    (https://gizmodo.com/reviews/other-gadgets) Other Gadgets    (https://gizmodo.com/reviews/wearables) Accessories & Wearables    (https://gizmodo.com/reviews/desktops) Desktops    (https://gizmodo.com/reviews/tablets) Tablets      (https://gizmodo.com/deals) Deals   (https://gizmodo.com/deals/buying-guides) Buying Guides      (https://gizmodo.com/science) Science   (https://gizmodo.com/science/biology) Biology    (https://gizmodo.com/science/health) Health    (https://gizmodo.com/science/human-history) Human History    (https://gizmodo.com/science/physics) Physics & Chemistry    (https://gizmodo.com/science/space) Space & Spaceflight      (https://gizmodo.com/earther) Earther   (https://gizmodo.com/earther/climate-change) Climate Change    (https://gizmodo.com/earther/conservation) Conservation    (https://gizmodo.com/earther/earth-science) Earth Science    (https://gizmodo.com/earther/energy) Energy    (https://gizmodo.com/earther/environmental-justice) Environmental Justice      (https://gizmodo.com/io9) io9   (https://gizmodo.com/io9/io9-reviews) io9 Reviews    (https://gizmodo.com/io9/movies) Movies    (https://gizmodo.com/io9/trailer-frenzy) Trailers    (https://gizmodo.com/io9/television) Television    (https://gizmodo.com/io9/books-comics) Books & Comics    (https://gizmodo.com/io9/anime) Anime    (https://gizmodo.com/io9/toys-and-collectibles) Toys & Collectibles    (https://gizmodo.com/io9/games) Games    (https://gizmodo.com/io9/corporate-culture) Corporate Culture    (https://gizmodo.com/io9/theme-parks-destinations) Theme Parks & Destinations       (https://gizmodo.com/video) Videos   Software  (https://gizmodo.com/best-vpn) Best VPN   (https://gizmodo.com/best-vpn/free) Free VPN   (https://gizmodo.com/best-vpn/cheap) Cheap VPN   (https://gizmodo.com/best-vpn/nordvpn) NordVPN Review   (https://gizmodo.com/best-vpn/expressvpn) ExpressVPN Review   (https://gizmodo.com/best-vpn/watch-world-cup) Watch World Cup 2026   (https://gizmodo.com/best-esim-provider/) Best eSIM   (https://gizmodo.com/best-cloud-storage) Cloud Storage   (https://gizmodo.com/best-cloud-storage/free) Free Cloud Storage   (https://gizmodo.com/best-cloud-storage/pcloud) pCloud Review   (https://gizmodo.com/best-web-hosting) Web Hosting   (https://gizmodo.com/best-web-hosting/hostinger) Hostinger Review   (https://gizmodo.com/best-antivirus) Best Antivirus     (https://gizmodo.com/download/) Download Hub     (https://gizmodo.com/about) About Us  (this-nasa-color-trick-was-meant-for-mars-now-its-unveiling-rock-art-on-earth-2000809844.html#) Other editions  (https://de.gizmodo.com/) Deutsch  (https://es.gizmodo.com) Español  (https://fr.gizmodo.com) Français  (https://www.gizmodo.com.br) Português    (https://gizmodo.com/jobs) Jobs  (https://gizmodo.com/how-gizmodo-tests-products) Product Review  (https://gizmodo.com/newsletter) Newsletters    (this-nasa-color-trick-was-meant-for-mars-now-its-unveiling-rock-art-on-earth-2000809844.html#) Your Privacy Choices  (https://gizmodo.com/privacy-policy) Privacy Policy  (https://gizmodo.com/terms-of-service) Terms of Use  (https://gizmodo.com/accessibility) Accessibility  (https://gizmodo.com/advertise-with-us) Advertising & Licensing    (Facebook) (https://facebook.com/gizmodo)    (Instagram) (https://instagram.com/gizmodo)    (X (Twitter)) (https://x.com/Gizmodo) 𝕏  (LinkedIn) (https://www.linkedin.com/company/gizmodo-usa)    (YouTube) (https://www.youtube.com/gizmodo)    (RSS) (https://gizmodo.com/feed)             (this-nasa-color-trick-was-meant-for-mars-now-its-unveiling-rock-art-on-earth-2000809844.html#) Bookmarks             Cookies settings