Transparent Umber is another colour with the “Oh Wow” factor. The earth colours have generally changed very little over the millennia and artists tend to think of earth colours as all being ancient in origin, but the situation is more complex than that.
Raw Sienna and Raw Umber as found in a modern tube of paint is virtually identical to the Raw Sienna and Raw Umber used 18,000 years ago by artists in caves in France. Red Oxide and Yellow Oxide have improved in purity during the 20th century by being made synthetically but the difference between the natural and the synthetic products are relatively small. Transparent Umber however is genuinely different.
There is no natural pigment that looks and behaves in a similar manner and it is totally an invention of the modern chemical industry in response to the demand, among others, of automobile manufacturers for new colours. Since cars typically are exposed to direct sunlight for 10 or more years, pigments used in auto paints need to have exceptional resistance to light. Transparent Red Oxide and Transparent Yellow Oxide fitted the requirements of colour and beauty as well as absolute stability in light so; extending the colour range of the transparent iron oxides into the dark brown range was a logical next step.
Chemical Description: Trans synthetic red oxide
Pigment Number: PR101
Lightfastness Rating: ASTM I
Pigment Opacity: Transparent
Paint Opacity: Transparent