Pigments in this group owe their name to the fact that most of them are made (or were made historically) of clay and earth minerals. The most common designation for these pigments is “PBrXX“, meaning “Pigment Brown”, but there are some yellow and red pigments in this group too. The Xs in the designation are digits which correspond to a certain chemical substance (or range of similar substances).
Naples Yellow usually ends up in this group, but I refuse to include it here, because it was a synthetic pigment originally (in fact, it’s one of the oldest synthetic pigments, as it dates back to 17th century; the real deal is no longer being made because it is toxic). I also don’t include sepia here, because it was historically made out of ink of some oceanic cephalopods (like squids or cuttlefish). Quinacridones are also absent, obviously.
Below, you will find the swatches of all the various earths that I have or had in my possession, imitations included. Swatches have two areas, the upper one to demonstrate the range of tints (diluted paint), and the lower one to show the mass-tone (the paint taken straight from the tube without diluting or, in case of the pans, the thickest concentration I could get). On each swatch you will notice a black line – I made it to give the idea about the transparency of the paint.