Umber
3 of the 6 encyclopedias on this shelf carry an entry for Umber. All 3 are reproduced below, so you can see where they agree and where they differ.
Collier's New Encyclopedia (1921)
a well-known pigment of an olive-brown color in its raw state, but much redder when burnt. It consists of an ocherous earth containing manganese, is durable, has a good body, and is useful in oil and water-color painting. It occurs either naturally in veins or beds, or is prepared artificially from various admixtures. That which is brought from Cyprus, under the name of Turkish umber, is the best. It is of a brown citrine color, semi-opaque, has all the properties of good ocher, is perfectly durable both in water and oil, and one of the best drying colors we possess. It injures no other good pigment with which it may be mixed. Also, a variety of peat or brown coal occurring near Cologne, used as a pigment and for the adulteration of snuff. In mineralogy, a clay-like substance of varying shades of a brown color, consisting essentially of a hydrated silicate of alumina mixed with varying proportions of iron and manganese oxides. Used as a pigment.
Aiton's Encyclopedia (1910)
a kind of earth used as a pigment in painting. The name is related to the Latin umbra, meaning shade. In its native condition umber has an olive color. It is opaque; it mixes well with oil; it wears well and associates readily with other coloring materials. When raw umber is roasted to drive out moisture a trace of iron present asserts itself and turns the pigment red. Raw umber gives a greenish yellow color to a house or painting; burnt umber produces a deep reddish brown. The best quality is a clay exported from Cyprus under the name of Turkish umber. A cheaper substitute is manufactured at Cologne from brown lignite coal. See Sienna; Painting
The Encyclopedia of Founding (1892)
A variety of hematite ore, composed of oxide of iron 48, oxide of manganese 20, silex 13, alumina 5, water 14. It is found in Cyprus; occurs massive; has no lustre; is brown and yellow in color; becomes a reddish brown when burnt, and in that state is used as an artist's color.
What Has Changed in the Last Century
The pigment itself is essentially as described: raw umber is still a hydrated iron oxide (goethite) earth whose defining ingredient is manganese oxide, and it still turns warm red-brown when roasted because heating dehydrates the goethite to hematite. Modern chemistry explains one of Collier's 1921 boasts "one of the best drying colors we possess" the manganese acts as a catalyst that speeds the oxidation of drying oils. Cyprus is still the classic source, and "Turkish" or Cyprus umber is sold today, though much of the brown on a modern palette is synthetic iron oxide rather than a mined earth. The one product that has quietly vanished is the Cologne lignite earth the 1910 and 1921 entries treat as a cheap umber substitute: as Cologne earth or Vandyke brown it proved fugitive and structurally unreliable in oil, and tubes bearing that name now hold blended substitutes.
Written for this edition, 2026.