Package ‘munsellinterpol’ June 7, 2018 Type Package Title Interpolate Munsell Renotation Data from Hue/Chroma to CIE/RGB Version 2.0.1 Encoding UTF-8 Date 2018-06-06 Description Methods for interpolating data in the Munsell color system following the ASTM D- 1535 standard. Hues and chromas with decimal values can be interpolated and con- verted to/from the Munsell color sys- tem and CIE xyY, CIE XYZ, CIE Lab, CIE Luv, or RGB. Based on the work by Paul Cen- tore, ``The Munsell and Kubelka-Munk Toolbox''. License GPL (>= 3) LazyLoad yes LazyData yes Depends R (>= 3.2.0), geometry, rootSolve Imports spacesRGB Suggests microbenchmark, mgcv, knitr, rmarkdown, flextable Author Jose Gama [aut, trl], Paul Centore [aut, cph], Glenn Davis [aut, cre] Maintainer Glenn Davis <[email protected]> Repository CRAN NeedsCompilation no VignetteBuilder knitr BuildVignettes yes Date/Publication 2018-06-07 17:43:13 UTC R topics documented: adaption . .2 CentroidsISCCNBS . .4 1 2 adaption ColorBlockFromMunsell . .5 ColorlabFormatToMunsellSpec . .7 HVCfromMunsellName . .8 IsWithinMacAdamLimits . 10 lab2xyz . 11 labtoMunsell . 12 luv2xyz . 13 luvtoMunsell . 14 Munsell2xy . 15 MunsellNameFromHVC . 17 MunsellSpecToColorlabFormat . 18 MunsellToLab . 20 MunsellToLuv . 21 MunsellToRGB . 22 MunsellTosRGB . 23 MunsellToxyY . 25 MunsellToXYZ . 27 plotLociHC . 28 plotPatchesH . 30 RGBtoMunsell . 31 srgb2xyz . 32 sRGBtoMunsell . 33 VandY............................................ 35 xyY2XYZ . 37 xyYtoMunsell . 38 xyz2lab . 40 xyz2luv . 41 xyz2srgb . 42 XYZ2xyY . 43 XYZtoMunsell . 44 Index 45 adaption Chromatic Adaption Description Adapt XYZ or xyY from a source viewing enviroment with a given illuminant, to a destination viewing environment with a different illuminant Usage adaptXYZ( XYZ.src, white.src, white.dest, method="bradford" ) adaptxyY( xyY.src, white.src, white.dest, method="bradford" ) adaption 3 Arguments XYZ.src an Nx3 matrix, or a vector that can be converted to such a matrix, by rows. Each row has an XYZ in the source viewing environment. xyY.src an Nx3 matrix, or a vector that can be converted to such a matrix, by rows. Each row has an xyY in the source viewing environment. white.src the XYZ or xyY of the illuminant in the source viewing environment white.dest the XYZ or xyY of the illuminant in the destination viewing environment method the method used for the chromatic adaption. Available methods are: "Bradford", "VonKries", "MCAT02", and "scaling". See References. Partial matching is enabled, and matching is case-insensitive. Details adaptXYZ() is the more fundamental of the two. adaptxyY() simply calls adaptXYZ() using xyY2XYZ() and XYZ2xyY() to do conversions. However, adaptxyY() does do an addition check: if the chromaticity of a row in xyY.src exactly matches that of white.src, then the returned chromaticity is set to be exactly the same as that in white.dest. Because of numerical truncation, it might not be. In adaptXYZ() the white coordinates are XYZ. In adaptxyY() the white coordinates are xyY. Value adaptXYZ() returns an Nx3 matrix with adapted XYZ in each row. adaptxyY() returns an Nx3 matrix with adapted xyY in each row. Analogy Chromatic adaption can be viewed as an Aristotelian analogy of proportions. A general analogy of this type is usually written A:B = C:D and read as "A is to B as C is to D". In our case the expression A:I is read as "the appearance of A in a viewing environment with illuminant I", or more simply "the appearance of A under illuminant I". It is better to think of A not as an object color, but as a self-luminous color. The analogy A : I = B : J can be read as "the appearance of A under illuminant I is the same as the appearance of B under illuminant J". Solving this problem of chromatic adaption is solving this analogy for X: A:I = X:J, where I is the the source illuminant and J is the destination illuminant. Note All these adaption methods are linear. For MCAT02 only the simplified linear variant is used. Linear methods (transforms) have these desirable properties: • symmetry: If A and B are viewing enironments, then adapting XYZ from A to B is the inverse of adapting XYZ from B to A. • commutative triangle: If there are 3 viewing environments, say A, B, and C, then adapting from A to B, and then from B to C, is the same as adapting from A to C. Equivalently (as- suming symmetry), a round-trip around the triangle is the identity. The property reduces to properties of matrix multiplication. The property makes it possible to use the intermediate Profile Connection Space (PCS) in v. 4 ICC color profiles. In the above-mentioned diagram, 4 CentroidsISCCNBS B represents the PCS, and A and C represent viewing environments for devices. The profile tag 'chad' is the chromatic adaptation matrix. According to Hunt p. 591, the non-linear CAT97 adaption transforms is not symmetric. I do not know whether any non-linear adaption transforms violate the second property, but guess that some do. Author(s) Glenn Davis References Hunt, R. W. G. The Reproduction of Colour. 6th Edition. John Wiley & Sons. 2004. International Color Consortium. ICC.1:2001-04. File Format for Color Profiles. 2001. Lindbloom, Bruce. Chromatic Adaptation. http://brucelindbloom.com/Eqn_ChromAdapt.html Wikipedia. CIECAM02. https://en.wikipedia.org/wiki/CIECAM02 See Also MunsellToRGB() CentroidsISCCNBS Centroid Notations for the Revised ISCC-NBS Color-Name Blocks Description CentroidsISCCNBS is a table with the centroids of the revised ISCC-NBS Color-Name Blocks. Format This data.frame has 267 rows and these columns: Number ISCC-NBS number (an integer from 1 to 267) Name ISCC-NBS name MunsellSpec Munsell specification of the centroid of the block a (character string) Details The earliest paper I am aware of is by Nickerson, et. al. in 1941. After the big Munsell renotation in 1943, the name blocks were revised in 1955. When the central colors were recomputed in Kelly (1958), they were called the "Central Colors", though the text makes it clear that most are truly centroids, which were computed from the centroid of an "elementary shape", which is a "sector of a right cylindrical annulus". For the "peripheral blocks" of high chroma, the centroids were "estimated graphically by plotting the MacAdam limits". In Kelly (1965) these were called "centroid colors", and that is the name we will use here. ColorBlockFromMunsell 5 Contributor Glenn Davis References Nickerson, Dorothy and Sidney M. Newhall. Central Notations for ISCC-NBS Color names.J Opt. Soc. Am. Vol 31 Iss. 9. pp. 597-591. 1941. 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. Kelly, Kenneth L. and Deane B. Judd The ISCC-NBS Method of Designating Colors and a Dictionary of Color Names. National Bureau of Standards Circular 553. Washington DC: US Government Printing Office. November 1, 1955. Kelly, Kenneth Low. Central Notations for the Revised ISCC-NBS Color-Name Blocks. Journal of Research of the National Bureau of Standards. Research Paper 2911. Vol. 61 No. 5. pp. 427-431. November 1958. Kelly, Kenneth Low. A Universal Color Language. Color Engineering. Vol. 3 No. 2. pp. 2-7. March-April, 1965. Examples print( CentroidsISCCNBS[ 1:5, ] ) ## Number Name MunsellSpec ## 1 1 vivid pink 1.5R 7/13 ## 2 2 strong pink 1.5R 7.5/9.1 ## 3 3 deep pink 1.9R 6.0/11.1 ## 4 4 light pink 2.5R 8.6/5.2 ## 5 5 moderate pink 2.5R 7.2/5.2 ColorBlockFromMunsell Get ISCC-NBS Number and ISCC-NBS Name from Munsell Hue, Value, and Chroma Description Get ISCC-NBS Number and ISCC-NBS Name from Munsell Hue, Value, and Chroma. Usage ColorBlockFromMunsell( MunsellSpec ) 6 ColorBlockFromMunsell Arguments MunsellSpec a numeric Nx3 matrix or a vector that can be converted to such a matrix. Each row has Munsell HVC, where H is Hue Number, and V and C are the standard Munsell Value and Chroma. The Hue is automatically wrapped to the interval (0,100]. MunsellSpec can also be a character N-vector with standard Munsell notation; it is converted to an Nx3 matrix. Details The ISCC-NBS System is a partition of Munsell Color Solid into 267 color blocks. Each block is a disjoint union of elementary blocks, where an elementary block is defined by its minimum and maximum limits in Hue, Value, and Chroma. Some blocks are non-convex. The peripheral blocks, of which there are 120, have arbitrary large chroma and are considered semi-infinite for this function; there is no consideration of the MacAdam limits. For each query vector HVC, the function searches a private data.frame with 932 elementary blocks, for the one elementary block that contains it. Value a data.frame with N rows and these columns: HVC the input Nx3 matrix, or such a matrix converted from Munsell notation Number the corresponding ISCC-NBS color number - an integer from 1 to 267 Name the corresponding ISCC-NBS color name - a character string Centroid the centroid of the block in Munsell Notation - a character string; see CentroidsISCCNBS The rownames are set to the input MunsellSpec. History The Munsell Book of Color was published in 1929. The first ISCC-NBS partition, in 1939, had 319 blocks and names (including 5 neutrals). There were no block numbers. The aimpoints of the Munsell samples were thoroughly revised in 1943. The ISCC-NBS partition was revised in 1955, and this is the version used here. Future Work It might be useful to compute the distance from the query point to the boundary of the containing color block. Author(s) Glenn Davis ColorlabFormatToMunsellSpec 7 References Munsell Color Company, A.H.