Dazzled by Limestone Cave Paintings




 I am bedazzled by the sheer innovation of painting on limestone, the chemical composition of which includes calcium carbonate.  I am amazed because we are still painting on gesso and using calcium carbonate as a key ingredient in artists’ paints.  Imagine for 100,000 years painters have had the technology to make paint but when did we start making paintings on limestone walls? 

Humans who fished did have an early need for oil varnish.  Before ancient boats could float, the wood had to be coated with oil/varnish mixture containing if not linseed oil then a progenitor.  They needed an oil varnish that hardened into a waterproof film.  When were colorants added to the oil varnish? Probably when I wanted to find my boat.

By adding colored pigments - carbon black, calcium carbonate white, yellow ochre, iron oxides and hematite to varnish, human had another way to differentiated objects.  Being able to select my boat from many boats seems like a good reason to add color.  The leap from using color to differentiate my boat to using color for storytelling is a long one.  Did original painters have a painting tradition before they found the caves or did they find the caves when they had something to say?

A breakthrough must have been finding bright limestone walls of caves undisturbed by animals or inhabited by humans, secure places to leave their paintings as messages, for rituals or ?  

Perhaps painters added a white wash then applied colors with some fluidity into dampened limestone walls in a manner similar to techniques used to make frescos by Egyptians, Romans, Greeks, Europeans among others.   As it dries, quicklime reacts with carbon dioxide in the air and convert to calcium carbonate.  Its components, calcite and aragonite form a crystalline structure across the painted surface, sealing in line and color.  

There are more than a million sites with cave paintings and rock art throughout Africa, the Americas, Asia throughout Europe and Indonesia.  Did original artists intend to leave messages - paintings at some sites were added on or over older ones for tens of thousands of years.  Were they recording animals’ migration patterns, in case they did not live long enough to transmit information to their grandchildren? 

Archeologists have not yet to find the oldest messages from our ancestors because there is at least a 50,000 year gap in our discoveries of paint making and cave paintings.  A painting of a red disk at El Castillo in Spain is at least 41,000 years.  

40,000 years ago cave paintings on the Indonesian Island of Sulawesi were created.  The famous caves of France and Spain date back 35,000 years.  A tablet painted with ochre, black and white was discovered in southwestern Namibia dated to between 26,300 and 28,400 BCE. The “National Geographic” reported on discovery of engravings, estimated to be about 15,000 years old, chiseled into several sandstone (containing calcium) cliffs at Qurta 400 miles south of Cairo.  Earliest indications of the Egyptian civilization as we imagine it emerged about 6000 BCE.  

Through the dynasties, Egyptians perfected a painting technique we’d call “secco” on lime plaster.  

As I understand their processes, the tempera style paints were applied then coated with beeswax.  The wax was then steamed into the surface, usually sandstone, the composition of which includes calcium.  Aside:  “Encaustic paints” were invented during the Arts & Crafts movement of the 19th century.  

Because colors on the paintings inside the pyramids were protected from sun and temperature variations, scientists and artists can still see the actual colors and analyze the colorants used.  Those colorants include the infamous Egyptian Blue made by heating calcium carbonate with a copper-containing compound (metal filings for example), silica plus potash as a flux to temperatures around 1500 degrees F .  

That is just about the same temperature at which calcium carbonate calcines so they had the technology to make both white pigment and Egyptian Blue thousands of years ago.

Above see Lapis and Egyptian Blue

Egyptian blue pigment was considered obsolete because its formulae had been corrupted during the Middle Ages. However conservators have found evidence that throughout the Renaissance and into the 18th century, Lapis lazuli was often adulterated with Egyptian blue. If no one thought the pigment existed, would they suspect they were looking at a mixture of Egyptian/lapis blue rather than pure lapis lazuli?   Maybe secrets of the Old Masters do exit.  

calcium carbonate

calcium carbonate