I do not drive anywhere without a little shovel and a box of plastic sandwich bags behind the front seat of my truck, to gather and collect small amounts of subtle shades of colored earth. Ochres, typically ranging from yellow to red, are natural earths consisting of clay, silica, and iron oxide in either anhydrous or hydrous form. I have found large chunks of pure limonite (yellow ochre) washed up on the shore of Lake Mead, pebbles of pure hematite (red iron oxide) in a dry stream bed in the Tucson Mountains, and a rich, deep red layer of burnt earth directly under the lava flow near Munds Park, Arizona. A captivating paper workshop at the University of Northern Arizona in 1983 lit more than a few light bulbs above my head and started my addiction to handmade paper. Like many other papermakers, I added natural sands and earths to my pulp. While the results were fine for some ideas, I was generally not satisfied with the loss of strength and increased weight in the sheet. I temporarily abandoned the use of gathered earth colors to pigment my papers (although vessels filled with a palette of raw earths were an element in one of my sculptural paper installations, The Clearing, from 1995). I met Norwegian paper artist Alison Leggat at a paper conference in Kyoto in 1995. We co-taught workshops in her studio in Oslo for the next five summers. Our mutual fascination with earth pigments as paper colorants became quickly apparent. Alison had been researching the use of earths from Kolsås, Norway, having read a brief article on pigments in Norwegian that sparked her interest. We could find nothing substantial published on or pertinent to the subject of natural pigments and nothing in print in English regarding the use of earth colors for artists. Through experimentation, trial and error, we began refining our studio techniques for washing, filtering, and grinding clays and soils to extract earth pigments. During the summer of 1999, we co-taught a pigment and paper workshop in Oslo. It was an interesting experience for all—students and instructors alike—as we extracted colors from Norwegian soil and mineral deposits and varied Arizona clays, sands, and earth, comparing the qualitative differences of the resulting pigments. We tested them as internal colorants with different paper fibers, using both Western and Japanese sheet forming techniques. Filtering the pigments from an earth sample obviously yields a much finer particle size and subsequent grinding creates uniformity of color throughout a sheet of handmade paper. Our collaborative lecture about filtering pigments at the August 2000 International Association of Papermakers and Paper Artists (IAPMA) conference in Sarteano, Italy, was met with great interest. Not being scientists ourselves, we welcomed the pertinent enumerations from the more experienced geologists and chemists in the audience. Pigments have a lighter weight than the sands or earths in which they can be found and, when mixed thoroughly with water, they will be the last layers to settle. Sometimes a single earth sample contains different colors (such as a red and a yellow), which can be seen as distinct layers. Grinding the sample before washing is at times appropriate. For instance, I have found that some of the harder earths from Arizona yielded greater quantities of pigment when I crushed them first. Alison and I developed a process that generally includes the following steps. The earth sample is soaked overnight before filtering; this tends to soften and dissolve any hard clays present. Then it is whisked thoroughly, to completely mix it with water, and poured through a metal sieve to remove any gravel, sand, or rocks. The process is continued, straining through finer and finer mesh with the final straining through silk. (The washed-out gravel and coarse sand from each washing can be saved in a separate bucket for a future washing to try to filter out even more pigment.) A final refined solution is whisked up and allowed to settle; the heavier layers settle first. The color still suspended in the water is scooped out and poured through several layers of coffee filters, which trap the pigment. Alison and I solved problems as we went, such as grinding the pigments carefully to a finer particle size. We achieved much better results when we ground the filtered earth pigments on a slab of marble, using either a glass muller or a hand-size piece of marble, making sure that all dry particles were thoroughly and evenly pasted up (somewhat like the preparatory grinding of a lithographic stone). According to Anne Wall Thomas, the quality of the color "...often depends on the size of the pigment particle. While most pigments are more intense if finely ground, others may become gray and almost devoid of color...Some colored earths have base components which are merely coated with particles of hematite and/or other coloring agents. Grinding, which pulverizes that base material, may reduce the color strength of the coloring agent considerably."1 I find it best to experiment by first grinding just a small amount of my filtered earth pigments. Wet, ground pigments can be used with a commercial retention aid directly with pulp or they can be allowed to dry. If you use distilled water, they can be stored in an aqueous-dispersed form in a covered jar for a longer shelf life. A classic source of information about pigment use for papermaking, Elaine Koretsky' s Color for the Hand Papermaker is a very good reference for techniques in pigmenting pulp. As each pigment has different characteristics and qualities, we found it necessary to experiment with the pigment-to-fiber ratio. For instance, a lot of the Arizona pigments were very translucent compared to the heavier, denser Norwegian ochres. Finally, using both traditional Western and Japanese techniques of sheet forming, we were able to achieve very refined papers in which the pigment particle is barely discernable. In August of 2000, I co-taught a workshop, "From Earth to Paper to Earth," with German paper artist Helmut Frerick at his wonderful home and studio, called "la font du ciel." We were in the tiny village of Charrus, in a valley of the nature reserve of the Ardèche Mountains in south central France. It was an exciting opportunity to completely make handmade paper from the landscape around us. We harvested, peeled, cooked, and hand-pounded fig and mulberry barks from trees on Helmut's property. Our formation aid was the mucilage garnered from crushing and soaking kiwi branches from a neighbor's tree. We dug, filtered, and ground our colorants ourselves, from some of the region's famous ochre deposits. With our workshop participants, we drove two hours to Roussillon (due east of Avignon), to learn about pigment extraction and processing at an industrial level. The hills in this part of Provence, in southeastern France, are richly striated with colored earths. This region is known as the source of some of the best ochres in the world, with colors ranging from light yellow to deep red. Two hundred thirty million years ago, the area was covered by sea. The ochres in this region evolved ever so slowly from more than one thousand meters of eroded sediment that accumulated under water. The red that is naturally present in the surrounding landscape results from the sun baking the surface; most of the earths found here are yellow. Our destination was the Conservatoire des Ocres et Pigments Appliqués, which was established by a non-profit association called Ôkhra. Mathieu and Barbara Barrois are the co-founders of the association and now act as directors of the Conservatoire. Located on an historical site that has been used for washing ochres since at least the1880s, the Conservatoire occupies some of the buildings of the last ochre factory to operate there, the Usine d'Ochre Mathieu, which was active from 1921 until 1963. With Ôkhra's support, the Conservatoire presents the opportunity for observing the historical process of filtering ochres each year. However Ôkhra's main goal is for the Conservatoire to act as a crystallization point for transmitting and developing knowledge and practical work concerning color in whatever instance. Once a year, in August or September, a symposium is held and professionals in the field gather for a day of scientific discussion. Each year the theme is different (in 2002 it was "Colors to Eat, Colors to Drink" and in 2003 the focus is "Colors and Metals"). As resources, the Conservatoire maintains a scientific laboratory for professional research and facilities for documenting the uses of pigments and color derived from plants, as well as a technical library with historical archives. The general public is invited to participate through guided visits of the factory (in French, English, and German), practical workshops in both traditional and new uses of pigments and other coloring substances and processes, and thematic exhibitions. There is also a wonderful bookshop, which sells a rich diversity of pigments and related supplies. I believe that only one commercial ochre-producing factory still operates in France, just outside the nearby town of Apt. It is run by the Société Ocrière de France and visits can sometimes be specially arranged by the Conservatoire. The traditional process of extracting pigment from the excavated earth takes an entire year from start to finish. The ochre-laden sands (approximately 80% to 90% sand and 20% to 10% pigment) are washed during the winter, because of the typical abundance of rain at that time, and are filtered through decantation. The pigment is allowed to dry through the summer and is then processed by grinding and burning in the fall. The excavated earth is mixed into a pool of water with an electrical mixer called a malaxeur. In a process called levigation, the sands settle and leave the pigments suspended in the water. At one end of the pool, holes drilled through just the top half of a flagstone gate (dalle percée) are unplugged. The top levels of pigmented liquid are allowed to flow into the bâtardeau, a deep, rock-lined trench, which acts like a transport canal. Descending in elevation, the ochre-charged water travels through a series of pierced gates, which act as obstacles for the heavier sands. The workers helping the liquid navigate down the bâtardeau can tell by tasting the surface if there is too much sand still in the water. Eventually the mixture flows into the bassin d'ocre, a basin where the pigments are allowed to settle. The water is recycled and pumped back up to the beginning of the process, where it is reused. By summer, the pigment in the bassin d'ocre is dry enough to cut into bricks. These are stacked to form walls, which are allowed to dry completely. The purest layer of color is in the top centimeter of each brick. In the autumn, the pigment is ready to be crushed in a mill or baked in an oven to create a range of red values. Yellow ochre is placed in an oven fired with oak wood to a maximum of five hundred degrees centigrade for fifteen to thirty-five hours. A skilled craftsman is sensitive to the varied smells at each stage of cooking and can determine each shade by scent. After the dry pigments have been ground into a fine powder, they are filtered through several layers of natural silk material. This process has caused some factory workers to develop breathing problems and lung disease. When we visited the Conservatoire in 2000, we saw a sculptural installation, by German artist Helga Brenner, in memoriam to those who fell ill. Bags of pigments were lined up on the floor and pigment-covered jackets were hung on the wall. This poignant work of art was reminiscent of earlier times, before environmental hazards were understood and preventative measures taken. It served as a great reminder to wear a good dust mask when working with dry pigments! Historically, pigments of the highest quality manufactured at the Usine Mathieu were exported for purposes for which a powerful colorant was needed, such as artists' supplies, paints of all kinds, and colorants for concrete. The second quality pigment (still slightly sandy) was used for the fabrication of linoleum. Earth pigments, used since the beginning of human history, are still considered the most permanent, despite the predominant use of synthetic colors in the commercial marketplace. Anne Wall Thomas states that, "They are not affected by sunlight or by atmospheric conditions—humidity, temperature, and impurities. They remain unaltered by contact with alkalis and dilute acids...[they] do not react with solvents and they have reasonable tinting strength and covering power. They have the capacity to screen harmful ultraviolet rays...and are invariably the least expensive pigments available. These characteristics account for their popularity with manufacturers of protective coatings for both wood and metal."2 Indeed, the most common house colors one sees everywhere in Norway and Sweden are yellow ochre and röd farg, a deep, rich red. I was told that these earth colored paints withstand the harsh Scandinavian winters for many years. Interestingly, today's paper industry rarely uses earth pigments as colorants,3 because their customers want standardized colors. Different oxidation levels and levels of quality cause variance in the colors of earth pigments making it impossible to reproduce exact hues. Because iron is a relatively reactive metal, though, chemists can control it for specific, reproducible synthetic colors. Iron oxides are inorganic pigments whose color can range from brown to red to yellow to green (umber to red oxide to ochre to terra verte) based on the amount of iron present, but they vary depending on the earth in which they are found. Other minerals found in a sample of iron oxide—such as carbonic materials, limestone, calcium, and manganese oxides—also affect the specific color of the pigment. Almost all naturally occurring iron oxides have a clay base (an eroded product of silicate rocks) that also influences the ultimate color. Iron oxides were used by prehistoric cave dwellers symbolically for cultural and spiritual rituals. There is evidence that prehistoric man traveled many miles to mine iron oxides, perhaps for their qualities of durability and richness of color. Some of the world's oldest prehistoric cave paintings have been found in the south of France. The paintings at Lascaux, perhaps the most famous of these, were created more than 16,000 years ago. Durability, permanence, and light fastness still make these pigments important for today's artist. To accompany this article, I have made paper samples of hand-beaten gampi fiber pigmented with a wonderful green earth that I dug just north of Moab in Utah. This particular earth is from the Brushy Basin member of the Morrison Formation and is dated to the Jurassic era, about 135-230 million years ago. A sedimentary rock, it contains quite a bit of clay. The green is iron that was not oxidized, which means it was laid down in a low oxidized environment (i.e., into water). Geologists have determined that a huge lake measuring 500 miles long and 300 miles wide covered a great deal of the Four Corners area (where the states of Utah, Colorado, New Mexico, and Arizona all meet). Volcanoes along the western shore of this lake spewed alkaline ash into the water, where it settled. Different levels of salinity resulted in varied shades of green (a bluish green can be found near Durango, Colorado).4 For contrast, I have pulp painted two Arizona pigments onto the samples. The first is from the red earth of Sedona, a fine-grained sedimentary sandstone. The magnificent rock formations in this area are similar to those of Utah's Monument Valley. And the second, a purple gray, was gathered in the Painted Desert, from Jurassic and Triassic sedimentary layers. The site is specifically known as the Owl Rock member of the Chinle Formation, along the road just west of Tuba City. The entire Painted Desert is a visual wonder of varied hues, whether marveled at from a distance or explored up close. Like the different colors found in iron oxides, colorful horizontal banding of sandstone and mudstone layers of the Chinle Formation resulted from a varying mineral content in the sediments and also from how quickly they were laid down. Concentrations of slowly deposited oxides of iron and aluminum create red, orange, and pink hues. A rapid sediment buildup, perhaps from a flood, caused oxygen to be removed from the soil and formed pale aqua, gray, and lavender layers.5 I find it fascinating to ponder colored earths and the magnitude of geological time. The immensity of it feeds my creative ideas. Using pigments from the earth gives a personal layer of meaning and experience to my images. Just as the act of gathering a specific plant from a particular location to make paper permeates my sheet, the earth pigments I have dug, filtered, and ground imbue it with the ancient.
Notes 1. Thomas, Anne Wall. Colors from the Earth: The Artists' Guide to Collecting, Preparing, and Using Them, Van Nostrand Reinhold Co., New York, New York: 1980. pg. 30. 2. ibid. pg. 24.3. From a conversation with artist/scientist Helmut Frerick, 2003. 4. From a conversation with Murray Shoemaker, Park Ranger, Arches National Park, Moab, Utah. 2003. 5. National Park Service web site, Geology. <http://www.nps.gov/pefo/painteddesert.htm>  Bibliography
Delamare, Francois & Guineau, Bernard. Colors: The Story of Dyes and Pigments, Harry N. Abrams, New York, NY: 2000.
Koretsky, Elaine. Color for the Hand Papermaker, Carriage House Press, Brookline, MA: 1983.
Nash, Catherine. "From Earth to Pigment to Paper", Earth - Bulletin #29, International Association of Hand Papermakers and Paper Artists. Autumn, 2000.
Nations, Dale & Stump, Edmund. Geology of Arizona, Kendall Hunt Publishing Company, Dubuque, Iowa: 1981.
Ocres, Parc Naturel Régional du Luberon & Édisud, co-editors. Aix-en-Provence, France: 1997.
Simonin, Francine. Les Ocres, de la belle marchandise...-Fabrication á l'Usine Mathieu - Roussillon 1920-1960, Éditions Ôkhra, Roussillon, France: 2000.
Thomas, Anne Wall. Colors from the Earth: The Artists' Guide to Collecting, Preparing, and Using Them, Van Nostrand Reinhold Co., New York, Hew York: 1980. (Interestingly, most of the direct pigment references in this book's bibliography are from the U.S Bureau of Mines. CN)  Resources
Ôkhra, Conservatoire des Ocres et Pigments Appliqué D104-84220 Roussillon, ProvenceFrance tel/fax +33 (0)4.90.05.66.69 For paper/pigment workshops and/or accommodations while in southern France and for help with arranging special visits of the Conservatoire or a visit to the special new museum about prehistoric caves exhibitions about "La Grotte Chauvet" in the Ardèche area (40 kilometers away), contact: Helmut Frerickla font du ciel moulin expérimental á papier La Chambary, Charrus F-97230 Saint André LachampFrance
tel/fax +33 (0)4.75.39.49.08 <lafontduciel@aol.com><http://www.frerick.de>