Tar Buckets

“Its use is advised against in every technique, including fresco.” These words were spoken by Max Doerner in his book, The Materials of the Artist and their use in Painting, copyright 1934. This book also has “Notes on the techniques of the Old Masters”, and is widely used by dinosaurs like me who have insatiable appetites for this type of information.

In his book, Doerner was advising against the use of asphaltum in painting. Doerner (1870- 1939) was a renowned professor in the Academy of Fine Arts in Munich for 25 years. He became respected for his knowledge of relationships between science and techniques of past master painters.

Asphaltum, or bitumen, is not really a tar but for our description here it is close enough. It is a naturally occurring residue of petroleum evaporation. Now, it is really difficult to imagine why artists began using this in their paintings, but it does have a beautiful golden brown color. It was used mostly as a glaze, meaning to tone a certain passage that had been painted and left to dry.

Asphaltum, which has an odd odor like tar, is actually not a pigment at all but a dye and artificial varieties are made of coal tar and brown coal. The way I have come to understand its use is that it diffuses when mixed with other colors, and thus must be mixed with an oil medium and painted over dried colors. It was used in the 17th century as a glaze by Rembrandt relatively successfully, mainly because he did not mix it with other colors.

In the 1800s other artists such as Prudhon, Hans Makart, and Hans von Marees used it freely, however they made the mistake of mixing it with other colors. Wide cracks began to appear in paintings where asphaltum had been employed.

Kurt Wehlte demonstrated during his lectures how asphaltum in oil and resin solutions can penetrate oil paint and ground layers, even as a final glaze.

I have never used authentic asphaltum in any of my artwork but there are a few suppliers who have replicated the color with more reliable pigments. In my experiments, just the right combinations of black, yellow and a red make a perfect substitute.

No need for those tar buckets after all.