NASA Mars color trick reveals Earth rock art
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The gist
NASA's decorrelation stretch, a 1978 JPL image technique, now reveals faded rock art on Earth.
It lets researchers see ancient paintings that are invisible to the naked eye.
Background
Decorrelation stretch was developed by researchers at NASA's Jet Propulsion Laboratory in 1978 to enhance contrasts in digital imagery and improve interpretation of high-correlation remote sensing and satellite imagery. It was later applied to Mars surface images, turning the rusty-red landscape into a mosaic of red, green, and yellow that exposed fine detail. Around 2005, rock art enthusiast Jon Harman saw those Mars before-and-after images at a conference and realized the same method could help study ancient, faded paintings.
How it unfolded
- 1978Researchers at NASA's Jet Propulsion Laboratory develop decorrelation stretch to improve interpretation of high-correlation remote sensing and satellite imagery.
- Around 2005Rock art enthusiast Jon Harman sees NASA Mars images with and without decorrelation stretch applied and recognizes its potential for studying ancient, faded images.
- Around 2005Harman finds a NASA paper explaining the algorithm, applies it to his own photos of rock art in Baja California, Mexico, and a new yellow figure appears in one image from the Cave of San Borjitas.
- Sep 8, 2026NASA publishes a tech-transfer article describing how the satellite-imaging algorithm now reveals ancient images.
Who’s saying what
- Expert
- Harman said the yellow figure that appeared in the Baja California image convinced him of the technique's usefulness for rock art research.