Tag Archives: medium


Okay, we got the paper, we got the pens and brushes—now we need the medium: ink.

Medium (singular), media (plural) are Latin words.

Medium is the word we artists use when we talk about the substance used to make marks—ink, paint, crayon, pencil, pastel, chalk. Every medium needs 2 parts: pigment and binder. The pigment is the color. You get pigment from vegetable, animal, or mineral sources. The binder is what holds the pigment together and makes it stick to a surface like paper. Liquid medium needs a third part: solvent.

To get black pigment, the Egyptians used the same stuff they did in pre-historic times: burned bones. When bones burn they turn black and brittle. The scribes ground them into a powder. You can use charcoal from wood, too.

This is a stone mortar and pestle—the tools you use to grind something into a powder.

To hold the powder together, they used the sap from the acacia tree. It’s called Gum Arabic and is still used in watercolor today. Gum Arabic is water-soluble. The Egyptian scribes would dry out the gum, grind it into a powder, mix it with burnt-bone powder and add water. They might add very little water to make a thick paste which they could form into a cake.

The round shapes at the top of this scribe’s kit are ink-cakes.

After the cake dried, a scribe could carry it around with him and reactivate the ink by adding a bit of water with his brush. Water is the solvent. If you’ve painted with a box of pan watercolors you understand what I mean. The scribe wrote on the papyrus with brush or pen and when the ink dried the pigment stayed there for thousands of years.

A set of pan watercolors

When they’re exposed to water and air, metals oxidize or corrode. As they do, they produce a colored outer layer. The Egyptians got red pigment by scraping the rust from iron. They got green or blue by scraping the corrosion off of copper.

The egyptologist in this article says ‘infers’ but he means ‘implies:’
This book is a must-read if you’re interested in color:

Back to the beginning of The Western Civ User’s Guide to Reading & Writing.

What do I paint second?

Michael asks:

Thanks so much for posting your technique, I am currently working on my first painting and have been doing exactly what you’ve done here. i think i did do something wrong though, a friend of mine said to do a light wash over the entire piece ,but I think it just confused me. Anyhow , why do you not put more detail in the underpainting, are you modeling further with your glazes?

I’m not sure what the light wash is for, either.  I’m assuming you’re using acrylic paints, which dry to a hard finish and so allow you to paint a wash on top of them.  I use gouache, and a wash would scrub off whatever was painted underneath.  So, I start my paintings with washes and build up to opaque brushstrokes. A wash is paint made transparent by adding water.  A glaze is paint made transparent by adding a medium—for acrylic, glazing medium; for oil paint, linseed oil and varnish—or glazing medium.

I do an underpainting to block in and organize big areas of light and dark.  I long ago found out it’s too complicated for me to figure out light and dark and color all at the same time.  There’s no point in me putting lots of detail in the underpainting, because I’m only going to paint the same details on top with opaque paint.  In fact, to discourage myself from getting into details while underpainting, I use an oversized brush.

Here’s a step-by-step example of how I build up from an underpainting.  This is a continuation of a previous post, What do I paint first?