How Were Petroglyphs, Pictographs, and Inscriptions Made?

Petroglyphs at Chaco Culture National Historical Park showing abrasion, drilling, and carving.

NPS photo.

Petroglyphs are carved into rock using stone tools. Various techniques made different shapes, forms, and textures. Sharp-edged, chipped tools made fine lines, whereas blunt tools left thicker lines. Chipping or abrading a patinated surface -- called “desert varnish” -- exposed the lighter color beneath. Abrasion prepared a surface or filled in a shape. Rubbing a stone sideways against the rock surface created texture. Drilling using sharp objects punched small holes in rock. Petroglyphs might show one or many of these techniques.

Wide-angle and detail of Navajo pictographs at Canyon de Chelly National Monument.

NPS photo.

Pictographs are painted on rock. People made paints from pigments ground from minerals and added to a binder to make a paste or liquid. People used calcium carbonate for white, hematite for red, yellow ochre for yellow, turquoise for blue, and charcoal for black. They mixed the minerals with plant or animal oils, saliva, eggs, blood, urine, grease or beeswax to help bind the pigment to the rock. The pigments were applied using tools such as sticks or brushes, or fingers and hands.

The “Beasley” inscription at Petrified Forest National Park.

NPS photo.

Inscriptions are carved into soft rock faces, such as sandstone, using sharp-edged, hard stones. The term typically refers to markings made by European peoples after they arrived in North America. Some inscriptions are attributed to Native Americans, as well.

Historic graffiti dated 1906 versus modern graffiti dated 2005.

NPS photos.

Graffiti consists of initials or marks, typically from the modern era. It may be carved or painted onto rock. The NPS preserves historic graffiti that is 50 years old or older.

Modern graffiti, however, is a problem across our public lands and is against federal law. People who use paint or carve on rock do irreparable harm to the resources. Please do your part to protect these fragile resources and enable the next visitor to enjoy them.

An artist's rendition of people chipping petroglyphs onto the rock surface of a canyon wall.

NPS image.

Think about carving or painting a mark on rock – it's not easy, or fast! Petroglyphs, pictographs, and inscriptions took time, planning, and teamwork to make.

Look closely for clues in the qualities of the rock face itself, the techniques chosen to create rock markings, and the styles or motifs. Consider if people constructed ladders, scaffolds or even a boat, to reach the site. Think about the relationship with the surrounding landscape and the relationship of the image to the sun, to other rock formations, and access points.

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Petroglyphs