Lab color scale

Create color scale that prints well on grayscale printers

Description

The function color_scale creates a color scale, or colormap, that is approximately uniform perceptually on both a color display and on a grayscale printer. The color scale is computed using the L*a*b* color space. It follows a uniform ramp along the L* direction, and it follows a semicircular path in the a*-b* plane.

The function color_scale_tool launches a GUI that allows you to experiment easily with different input parameters for color_scale.

For more information about these functions, see my image processing blog posting, http://blogs.mathworks.com/steve/?p=57

• Acknowledgements: This submission has inspired the following:; Bipolar Colormap, Perceptually improved colormaps
• Required Products: Image Processing Toolbox
• MATLAB release: MATLAB 7.2 (R2006a)

[hassan quzmar]

 

[michal sh]

 

[Alexandre Tumlinson]

Take a look at 'colorGray' which has similar functionality but with "rainbow" like color spectrum.

[Matteo Niccoli]

Steve,

I do not have image processing toolbox, so I cannot really run this code. But I give the submission a 5 based on your excellent post. It was really useful for me to learn more on how to work in Lab space. I modified the code snippet in your post and combined with cline and colorspace to display L plot using the resulting RGB color:

% radius = 50;
% theta = linspace(0, pi/2, 256).';
% a = radius * cos(theta);
% b = radius * sin(theta);
% L = linspace(0, 100, 256).';
% Lab = [L, a, b];
% RGBhlx=colorspace('RGB<-Lab',(Lab));
% figure; cline(a, b, L, L,RGBhlx); view(3);
% VIEW(-165,-15);