HVCfromMunsellName {munsellinterpol}

Convert Munsell Notation to numerical Munsell HVC

Description

Convert Munsell Notation to numerical Munsell HVC

Usage

HVCfromMunsellName( MunsellName )
MunsellHVC( MunsellName )
HueNumberFromString( HueString )

Arguments

MunsellName

a character vector of length N > 0, where each string should be a valid Munsell notation, e.g. '2.3P 5/2.3', '9.2YR 3/6', 'N 2.3/', and 'N 4/0'. Whitespace is optional and ignored. It is OK for a neutral to end in either '/' or '/0'.

HueString

a character vector of length N > 0, where each string should be the initial hue part of a Munsell notation, e.g. '4.5GY', '2.5R', '10.3B', etc. Whitespace is optional and ignored. Neutrals, denoted by 'N', are invalid because the hue is undefined.

Value

HVCfromMunsellName() returns a numeric Nx3 matrix with HVC in the rows. For neutral colors, both H and C are set to 0. If a string cannot be parsed, the entire row is set to NAs. The rownames are set to MunsellName.
MunsellHVC() returns a character Nx3 matrix with HVC in the rows, and is there for backward compatibility with older versions of the package. For neutral colors, H is set to 'N' and C is set to '0'.
HueNumberFromString() returns the hue number H (in (0,100]). If the string cannot be parsed, or the color is neutral, the output is set to NA.
For all functions the Hue Number is wrapped to (0,100].

Note

Ever since the Munsell Book of Color (1929), the Munsell hue circle has been divided into 10 principal hues or arcs. And each principal hue has been assigned a 10-point scale, with 5 at the midpoint of the arc. Moreover, the hue "origin" has been at '10RP'. So a 100-point scale (with no letters) for the entire hue circle is obvious and trivial to construct, but I have been unable to determine the first explicit mention of such a scale. The earliest I have have found is from Nimeroff (1968), Figures 20 and 21 on page 27.

There is a reference to ASTM D 1535 in the References of Nimeroff, but it is not dated, and the 2 figures are not attributed to it. There was an ASTM D 1535 in 1968 but I have not been able to locate it; it is possible that the 100-point scale first appeared in ASTM D-1535 (1968), or even earlier in ASTM D 1525-58T (1958).
Interestingly, in the Atlas of the Munsell Color System (1915) there were only 5 principal hues, and each arc was assigned a 10-point scale. If the entire hue circle of 1915 were assigned a scale, it would have been a 50-point scale.

Author(s)

Glenn Davis

References

Nimeroff, I. Colorimetry. National Bureau of Standards Monograph 104. January 1968. 35 cents.

ASTM D 1535-80. Standard Practice for Specifying Color by the Munsell System. 1980.

Munsell Book of Color: defining, explaining, and illustrating the fundamental characteristics of color. Munsell Color Co. 1929.

Atlas of the Munsell Color System. Malden, Mass., Wadsworth, Howland & Co., inc., Printers. 1915.

See Also

MunsellNameFromHVC(), HueStringFromNumber()

Examples

HVCfromMunsellName( c( "4.2P 2.9/3.8", "N 2.3/", "N 8.9/0" ) )
##                  H   V   C
##  4.2P 2.9/3.8 84.2 2.9 3.8
##  N 2.3/        0.0 2.3 0.0
##  N 8.9/0       0.0 8.9 0.0

HueNumberFromString( c('4B','4.6GY','10RP','N') )
##  [1]  64.0  34.6 100.0    NA