Soil Thresholds (various locations), Claire Pentecost

Chromatography refers to a variety of laboratory techniques for physically separating the parts of a complex mixture. As part of her ongoing artistic work appreciating soil, Pentecost employs a particular method of soil chromatography advanced by Ehrenfried Pfeiffer in the mid 20th century. As a pioneer of biodynamic agriculture, Pfeiffer used paper filter chromatography to produce qualitative visual information about a given soil. The resulting chromatograms are something like portraits, debatably closer to art than to science. Similar to a fingerprint, they document the unique nature of various soils. No two soils will deliver an identical image, although the particular variations may be subtle.
Pentecost has collected soil samples for different projects over the years. Many of the soils pictured in this exhibition were collected as part of an exploration of the Wisconsin Driftless region, a terrain that escaped glaciation in the last glacial period and is noted for its deeply carved river valleys.