Field Analysis:How Colour

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Soil Colour
Soil colours should be recorded out of direct sunlight, from the moist (moistened if necessary) surface of a freshly broken aggregate (not smeared). The dominant matrix colour should be recorded together with the presence and colour of any mottles.

Munsell colour recording
The Munsell&reg; Soil Colour Charts are the best way of systematically recording colour. The Hue (principal colour), Value (lightness) and Chroma (purity or strength) are recorded as shown below. First find the colour sheet that most closely reflects the hue of the sample. Then scan up and down on this sheet to find the value and finally left to right to find the closest colour match and the appropriate chroma.

Freeware Munsell&reg; Conversion software is widely available for download at a number of internet sites, for example here.

Non-Munsell colour recording
In the absence of a Munsell&reg; chart a number of alternative systems exist that involve picking colours from a given list, and where necessary adding a modifier such as light dark or mottled. These schemes are not directly compatible with the Munsell&reg; system.

The Museum of London Archaeology Service (MoLAS, 1994) provide one such scheme.

Mottling
The uniformity of soil colour can be recorded as:
 * Uniform
 * Mottled
 * Gradual vertical change
 * Gradual lateral change

Mottle colours should be recorded in the same way as the matrix colour and their abunadance and contrast or prominence should also be recorded. It may also be interesting to note any spatial relationships between for example mottling and inclusions, voids, roots or aggregate surfaces that exist.

Mottle abundance
Choose the abundance class based on the percentage surface area that is affected by mottling. Use the frequency charts below to help select the appropriate class.



Mottle contrast
Record also the contrast between the mottling and the surrounding matrix colour.

Mottle composition
Where the mineral or organic make up of the mottles clearly differs from that of the surrounding soil matrix, this may be recorded in general comments.

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