standardXYZ: Query the Standardized XYZ and xy values of Standard...
In spacesXYZ: CIE XYZ and some of Its Derived Color Spaces

standardXYZ

R Documentation

Query the Standardized XYZ and xy values of Standard Illuminants and Whitepoints

Description

In careful calcuations with standard illuminants and whitepoints, it is often helpful to have the 'official' values of XYZ and xy, i.e. with the right number of decimal places.

Usage

standardXYZ( name )

standardxy( name )

Arguments

name

a subvector of c('A','B','C','C.NBS','C.NTSC','C.JOSA','D50','D50.ICC',
'D55','D60','D65','D75','E','F2','F7','F11','ACES','DCI'), which are the names of some standard illuminants and white points. Matching is partial and case-insensitive.
name can also be NULL or '*' which means to return all available data.

Details

All XYZ values are taken from the ASTM publication in References, except B which is taken from Wyszecki & Stiles and D50.ICC which is taken from ICC publications.

xy values were taken from CIE, BT.709, SMPTE EG 432-1, and TB-2018-001. For D65 the values in CIE and BT.709 disagree; the former has 5 digits and the latter has 4. We have selected the value in BT.709 (page 3) since is far more commonly used. Three of the Illuminant C variants are rarely used and obsolete.

Value

standardXYZ() returns an Mx3 matrix where M is the length of name. But if name is NULL or '*', M is the number of records available. Each row filled with the official XYZ, but if the illuminant name is not recognized or if there is no data, the row is all NAs. The output XYZ is normalized so that Y=1. The matrix rownames are set to the full illuminant names, and colnames to c('X','Y','Z').

Similarly, standardxy() returns an Mx2 matrix with colnames set to c('x','y').

Warning

The returned XYZs are normalized so that Y=1. In other color domains, it is common to normalize so that Y=100; in these cases be sure to multiply by 100.

Some illuminants have no standard XYZ available and some have no standard xy. In these cases, the rows are filled with NAs.

References

ASTM E 308 - 01. Standard Practice for Computing the Colors of Objects by Using the CIE System. 2001.

BT.709. Parameter values for the HDTV standards for production and international programme exchange. June 2015.

CIE 015:2004 - Colorimetry, 3rd edition. International Commission on Illumination (CIE). Vienna Austria. Technical Report. 2004.

Günther Wyszecki and W. S. Stiles. Color Science: Concepts and Methods, Quantitative Data and Formulae, Second Edition. John Wiley & Sons, 1982. Table I(3.3.8) p. 769.

TB-2018-001. Derivation of the ACES White Point CIE Chromaticity Coordinates. The Academy of Motion Picture Arts and Sciences. Science and Technology Council. Academy Color Encoding System (ACES) Project. June 15, 2018.

SMPTE RP 431-2. D-Cinema Quality - Reference Projector and Environment for the Display of DCDM in Review Rooms and Theaters. 2011.

Examples

standardXYZ( c('a','d50','D50.ICC','D65') ) 
#                 X Y         Z
# A       1.0985000 1 0.3558500
# D50     0.9642200 1 0.8252100
# D50.ICC 0.9642029 1 0.8249054
# D65     0.9504700 1 1.0888300

standardxy( c('a','D65','D60','D60.ACES','E','F2') )
#                x       y
# A        0.44758 0.40745
# D65      0.31270 0.32900
# D60      0.32163 0.33774
# D60.ACES 0.32168 0.33767
# E        0.33333 0.33333
# F2            NA      NA

spacesXYZ documentation built on May 29, 2024, 6:33 a.m.