May 22, 2014
A simple colour example
Two colour wheels, one using red-green-blue colour coordinates based on how monitors work, the other using a rescaled coordinate system based approximately on what the eye sees
The second set of colours isn’t as dramatic, but they are much better at being evenly spaced around the circle and equally bright.
Thomas Lumley (@tslumley) is Professor of Biostatistics at the University of Auckland. His research interests include semiparametric models, survey sampling, statistical computing, foundations of statistics, and whatever methodological problems his medical collaborators come up with. He also blogs at Biased and Inefficient See all posts by Thomas Lumley »
However, the second set of colours is not good design for someone who is colour blind. A red-green colour blind person will not be able to easily distinguish 8,9,10,11 in the second circle although 2,3,4,5 are probably ok for them.
Colour blindness is an aspect far too often overlooked by designers of graphics.
10 years ago
True. I think there’s really no way to encode angles that works for people with dichromatic vision (I do know about this — I’ve written software to let people see what their graphs and colour palettes in R look like with either type of red:green colour blindness)
10 years ago
Interesting choice of colours.
Roughly speaking your pattern can be represented well in LCH space where I assume it was designed
L=70
C=35
H= 15(30)345
where colour 1=15, colour 2=45 etc.
In response to the comment about the colours being undramatic, I wonder what more L and/or C would do to this (assuming that gamut limitations of display and print devices allow)
for example, what would the same H pattern with C=70 look like, and perhaps higher L
In terms of the red green colour blind problem, has this been documented in LCH or Lab space?
Is it simply that the two half planes a and -a (In Lab terms) cannot be separated when this vision deficiency prevails?
If this is the case it is hard to see how one would make a cyclic colour wheel suitable for red/green colour blindness?
This web site shows some examples.
http://www.archimedes-lab.org/colorblindnesstest.html
As suggested opposite sides of the colour wheel are indistinguishable.
Interesting aside!
Bob Jordan
10 years ago
Yes, the colour wheel was created in Lch space, by the hcl() function in R. And yes, the problem with angles is that in dichromacy you lose one of the two opponent-process dimensions, so a constant-luminance colour space is one-dimensional and doesn’t have room for a circle.
10 years ago