E is for Earth

I think that we, as modern artists, really can’t be blamed for being spoilt with colour. It is the wonderful colourmen out there, now colour scientists, ever seeking new ways to bring forth colour in lightfast and economical ways. Did you know that we have a lot to thank car manufacturers for? Where do you think the demand for strong, lightfast colours originally came from? I know what the Australian sun is capable of – I had a red car for ten years and no carport to shelter it with. I saw its paint get literally eaten…and I won’t mention what happened to the sun-exposed upholstery. The colour of your car has a long history of scientific colour research behind it, and that research bled into the artistic paints (and other uses for pigments) we see today.

But I drift off my letter. Today is E, and E is for Earth…the most lightfast pigments of all.

The first colour pigments the human race ever used were the Earth pigments. We are talking clays. You tend to see these translated into red and yellow ochres. Collected from sacred sites ( Australian Aboriginal people, up until around two hundred years ago would trade in ochre, and if you’ve ever seen Rainbow Valley, you would know why) and mixed with a variety of binders from saliva to animal fat to form paints. Australia has many ancient painting sites with the Aboriginal communities inhabiting this land for over 40,000 years, and their cave paintings ancient and new decorate many a site.

The painting above is from a cave in Spain – Cave of Altamira. Apparently it is full of such paintings dating from 20,000 – 35,000 years ago. I’d call that pretty lightfast.

But what do these pigments mean for the modern artist? Do we still use them?

Most definitely.  Of course, our binders tend to come from different sources. I think the average cave artist would have been tickled pink to have access to an acrylic polymer emulsion. There have also been some synthetic versions created

So which of our pigments come from these traditional Earth sources?

Here are a few familiar names:

• Red Ochre PR102 – calcined (roasted) natural red iron oxide,based on deposits of hematite, an iron oxide/ore that is the main source of iron for the steel industry, often called ‘rust’. PR101 is the synthesized version of this pigment. Looking through my paints, my red oxides all contain 101. Names for Red Ochre colours – Indian Red, Light Red, Persian Red, Red Oxide, Sinopia, Terra Rosa and Venetian Red.
• Yellow Ochre PY43 – natural yellow iron oxide based on deposits of limonite. Apparently the higher the iron content, the darker the colour. PY42 is synthetic yellow iron oxide. Some colour names include Yellow Oxide, Deep Ochre, Flesh Ochre and Bronze Yellow.

  

• Green Earth PG23 – often called Terre Verte is not an iron oxide, but is sourced from marine clays containing iron silicate. Two main colours are created depending upon the mineral composition – celadonite produces a bluish gray and glauconite a dark brownish olive. Natural Green Earth deposits have become almost exhausted as they were much rarer than the iron oxides. Consequently most Green Earth colours are now created using either Phthalo (PG7) or Viridian (PG18). Some common names include – Olive Green, Green Umber, Venice Green and Rhenish Earth.
• Chalk – Whiting PW 18 – Calcium carbonate and Gypsum PW25 – Calcium sulphate. While these two aren’t traditionally used as pigments in paint, I’m sure the pastel users amongst us could vouch for their value. Both were used by ancient artists and both are still in use today.
• Black – although not derived from the Earth, I think the blacks deserve a quick mention here as along side all those pigments above, black was a core colour in ancient times. Often derived from either burnt animal fats or perhaps burnt wood, the processes used today do not correspond enough to give them a defined pigment name, but carbon black, lamp black and perhaps vine black share their origins.

A couple of really familiar names are Sienna and Umber so they deserve a quick note here.

Raw Sienna is an orange-brown colour produced from a natural yellow-brown earth oxide containing iron and manganese. Originally mined near Siena, Tuscany in Italy, this is where its name came from (though now the mines are exhausted so it is sourced from other regions of Italy). If you calcine (roast) Raw Sienna, you create Burnt Sienna. The natural pigment PBR7 – natural iron oxide is often combined with a synthetic red oxide PR101 to create Burnt Sienna (and I have proof with the very paint sitting here on my desk with those two numbers on its label).

Raw Umber is a greenish-brown Earth colour that also is obtained from oxides containing iron and manganese. And if you roast it you get Burnt Umber. Again a combination of natural and synthtic pigments create the colours bearing this name today. ‘Umber’ is thought to originate from the Latin word ‘Umbra’ meaning shadow, of which many it has painted. Both my Raw Umber and my Burnt Umber use the natural pigment PBr7.

When I was a kid we had some friends who were building a house not far from an old quarry. Being kids we played in the quarry which was literally dripping with clay deposits (it was winter, there was rain, and can we say mud?). Little did I know that I was playing with the raw ingredients of the paints I would end up painting with as an adult. There were several different colours and I had the time of my life getting myself coated in them. The quarry is gone now, eaten by housing estates, but it would be fun to go back and look at those colours and wonder.

Best wishes,
Liz
(who lives in a country streaked with coloured ochres)

See all my Blogging A to Z posts here!