The human eye can distinguish less than 100 grays, but more than 10,000 colors. The use of color can reveal by design or accident new and very subtle features in the data. A well-designed color palette can artfully emphasize difficult-to-see anomalies. At the same time color can be distracting to the eye. It can emphasize certain features of an image and downplay others, leading to confusion about the strength of anomalies and what actually lies in the data. For this reason many investigators prefer the gray scale as an unbiased indication of patterns in a data set.

The electrical resistance data set in this slide show is of a 10 x 10 m region, acquired with a probe separation of 50 cm (click here to restart slide show if not displayed). It represents the footprint of Sluss Cabin, an 1870s frontier cabin in central Kansas. Based on limited testing we know that it had a stone foundation with two rooms, one with an earthen floor (right) and the other made of fist-size cobbles (left). The stone is highly resistant generating good contasts, but can any details be seen in the cobble floor and can it be distinguished from the larger cut-stone foundation blocks? Certain color palettes allow some of these features to be better distinguished. Moreover, it may be possible to discern very subtle linear anomalies extending upward and to the right from the cabin that may represent footpaths leading from the cabin, possibly seen owing to differences in soil compaction that mildly raise soil resistance.

Other modes of display may also enhance visualization of these features.

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