RGB2RYB function

Convert RGB to RYB and RYB to RGB

Convert RGB (red-green-blue) colours to RYB (red-yellow-blue) colours, and vice versa. Algorithm based on Sugita and Takahashi (2015, 2017)

RGB2RYB(RGBmat)
RYB2RGB(RYBmat)

Arguments

• RGBmat: numeric -- matrix of red-green-blue primary colors by column, where rows are individual records of the three primary (RGB) colours. User can specify RGB in terms of 0-1 or 0-255; however, the algorith converts the latter to 0-1.
• RYBmat: numeric -- matrix of red-yellow-blue primary colors by column, where rows are individual records of the three primary (RYB) colours. User can specify RYB in terms of 0-1 or 0-255; however, the algorith converts the latter to 0-1.

Details

The RYB colour wheel is more commonly used by artists, and provides a more intuitive system when blending colours -- red and yellow makes orange, yellow and blue makes green, blue and red makes purple. On the RYB colour wheel, red lies opposite green, but on the RGB colour wheel, red lies opposite cyan.

Returns

Matrix of RGB or RYB primary colour intensities, where rows are records and columns are primary colours.

References

Sugita, J. and Takahashi, T. (2017) Computational RYB Color Model and its Applications. IIEEJ Transactions on Image Electronics and Visual Computing 5(2): 110-122.

Sugita, J. and Takahashi, T. (2015) RYB Color Compositing. International Workshop on Applications in Information Technology, October 8-10, 2015.

Author(s)

Rowan Haigh, Program Head -- Offshore Rockfish

Pacific Biological Station (PBS), Fisheries & Oceans Canada (DFO), Nanaimo BC

locus opus: Regional Headquarters, Vancouver BC

Last modified Rd: 2022-07-06

Note

Opposite colours calculated in RYB space (1-RYB) are not always what one expects. For example the colour "purple", RGB {160, 32, 240}, might better be specified as RGB {126, 0, 255} before converting to RYB and inverting.

See Also

In package PBSmapping:

addBubbles

In package grDevices:

col2rgb, rgb, rgb2hsv