plotLociHC: Plot Curves of Constant Munsell Hue and Chroma

In munsellinterpol: Interpolate Munsell Renotation Data from Hue Value/Chroma to CIE/RGB

Plot Curves of Constant Munsell Hue and Chroma

Description

Plot Curves of Constant Munsell Hue and Chroma

Usage

plotLociHC( value=5, hue=seq(2.5,100,by=2.5), chroma='auto', coords='xy',
                        main="Value %g/", est=FALSE, ... ) 

Arguments

value	a Munsell value for which the plot is created. It must be in the interval (0,10]. value can also be a numeric vector of such numbers, and then a separate plot is made for each element of the vector.
hue	a numeric vector for which curves of contant Hue are plotted. Each of these radial curves starts at Munsell Chroma = min(chroma,1) and extends to max(chroma). hue can also be a character vector, which is then converted to a numeric vector using HueNumberFromString().
chroma	a numeric vector for which ovoids of constant Chroma are plotted. Each of these ovoids is closed; i.e. goes full circle from Hue=0 to Hue=100. If chroma='auto' then a vector is chosen appropriate for the current value.
coords	either 'xy' or 'ab'. If coords='xy' then the plots are in the standard xy chromaticity plane. If coords='ab' then the plots are in the ab chrominance plane, from Lab. Even when it is 'ab', the interpolation of loci takes place in 'xy' before transformation to Lab.
main	a string used to set the main title of the plot. The optional placeholder '%g' is replaced by the current value.
est	if TRUE, initial estimates for the iteration used in xyYtoMunsell() are plotted
...	other arguments passed to the function MunsellToxyY(). This includes hcinterp, vinterp, and xyC. However warn=FALSE is forced.

Details

The plot limits (xlim and ylim) are set to include all points where the Hue radials intersect the Chroma ovoids, plus the white point.
If value is one of {0.2,0.4,0.6,0.8,1,2,3,4,5,6,7,8,9,10} then published points from real.dat are plotted with filled black points (real points), and extrapolated points from all.dat are drawn with open circles (unreal points).

Value

TRUE for success and FALSE for failure.

Condition Signaling

For an overview see: Appendix E - Logging and Condition Signaling in the User Guide.

In case of an ERROR or FATAL event, an error condition is signaled with one of these additional S3 classes: "invalid_argument" or "package_unavailable" or "internal_error", whichever is appropriate. The invalid argument, or the name of the unavailable package, is added to the condition object.

In case of an WARN event, a warning condition is signaled with the additional S3 class "incomplete". The condition object also has the the subvector of Value's that could not be plotted as item invalid, and their indexes as item indexes.

Note

The option hcinterp='bicubic' makes fairly smooth ovoids, and hcinterp='bilinear' makes 40-sided polygons (when coords='xy'). Compare with the plots in Newhall et. al. (1943), Judd, et. al. (1956), and Judd, et. al. (1975) p. 263.

Author(s)

Glenn Davis

References

Newhall, Sidney M., Dorothy Nickerson, Deane B. Judd. Final Report of the O.S.A. Subcommitte on the Spacing of the Munsell Colors. Journal of the Optical Society of America. Vol. 33. No. 7. pp. 385-418. July 1943.

Judd, Deane B. and GC<nther Wyszecki. Extension of the Munsell Renotation System to Very Dark Colors. Journal of the Optical Society of America. Vol. 46. No. 4. pp. 281-284. April 1956.

Judd, Deane B. and GC<nther Wyszecki. Color in Business, Science, and Industry. 3rd edition. John Wiley & Sons. 1975.

See Also

MunsellToxyY(), HueNumberFromString()

munsellinterpol documentation built on July 30, 2026, 5:12 p.m.