colorContrast {aqp} | R Documentation |
Pair-wise comparisons of Munsell color specifications, based on the NCSS color contrast classes (Soil Survey Technical Note 2) and CIE delta-E 2000 metric.
colorContrast(m1, m2)
m1 |
vector of Munsell colors ('10YR 3/3') |
m2 |
vector of Munsell colors ('10YR 3/6') |
This function is fully vectorized but expects input to be of the same length. Use expand.grid()
to generate suitable input from 1:many or many:1 type comparisons. See this tutorial for an expanded discussion and more examples. Neutral colors are not mentioned in SSTN2: in this function any comparison to a neutral color (e.g. 'N 3/') are assigned a delta-hue of 1. Since SSTN2 expects hues to be counted clock wise from 5R, it possible to get very large delta-hue values for otherwise adjacent colors: '5R' vs. '2.5R'. This will be addressed in an update to the standards.
The most meaningful representation of color contrast is the CIE2000 (dE00) metric.
A data.frame
with the following columns:
m1: Munsell color 1
m2: Munsell color 2
dH: delta-hue, as computed by huePosition
dV: delta-value, absolute value of difference in Munsell value (m1 vs. m2)
dc: delta-chroma, absolute value of difference in Munsell chroma (m1 vs. m2)
dE00: delta-E00, e.g. the CIE delta-E as refined in 2000
cc: soil color contrast class, as specified in Soil Survey Technical Note 2
delta-E00 is computed by the farver package.
D.E. Beaudette
https://en.wikipedia.org/wiki/Color_difference
colorContrastPlot, huePosition, huePositionCircle
# two sets of colors to compare m1 <- c('10YR 6/3', '7.5YR 3/3', '10YR 2/2', '7.5YR 3/4') m2 <- c('5YR 3/4', '7.5YR 4/4', '2.5YR 2/2', '7.5YR 6/3') # contrast metrics colorContrast(m1, m2) # adjacent chips colorContrast('10YR 3/3', '10YR 3/4') colorContrast('10YR 3/3', '7.5YR 3/3') # highly contrasting colors # http://colour.granjow.net/fabercastell-polychromos.html colorContrastPlot('10B 4/13', '10YR 10/15', labels = c('helioblue-reddish', 'light cadmium yellow') ) ## Note: neutral hues aren't defined in TN2 # approximation / extension of the concept colorContrast(m1 = 'N 3/', m2 = 'N 6/') # colorContrast(m1 = '10YR 3/3', m2 = 'N 3/') m1 <- c('10YR 6/3', '7.5YR 3/3', '10YR 2/2', 'N 3/') m2 <- c('5YR 3/4', '7.5YR 4/4', '2.5YR 2/2', '7.5YR 6/3') colorContrast(m1, m2)