Final answer:
Umber is a brown or reddish-brown earth pigment with iron and manganese oxides, which becomes darker when heated. Ochre is a natural earth pigment that ranges from yellow to deep orange or brown, and it doesn't darken under light exposure. Both pigments have been historically significant in art for their earthy tones and mixing capabilities.
Step-by-step explanation:
The difference between Umber and Ochre relates to their color properties and the materials from which they are derived. Umber is a natural brown or reddish-brown earth pigment that contains iron oxide and manganese oxide. In its natural form, it often comes from a dark brown to a near-black color. When heated (burnt), umber becomes a darker brown and is often referred to as burnt umber. Historically, it has been used in art since prehistoric times and provides a rich, deep color in paintings.
On the other hand, Ochre is a natural clay earth pigment which is a mixture of ferric oxide and varying amounts of clay and sand. It ranges in color from yellow to deep orange or brown. One of the unique properties of ochre is that it does not darken when exposed to light over time, making it a popular choice among artists for its stability. Ochre is also one of the oldest pigments used by humans, and it was a key part of the palette used by ancient artists, including Indigenous cave dwellers, who utilized pigments made from natural materials.
Mixing ochre with black creates different shades of the color, while mixing it with white lightens its hue. This results in a spectrum of earth tones that was used to create visuals with depth and realism, especially valuable in eras such as the Renaissance where the depiction of chiaroscuro and nuanced shading was essential.