As of MATLAB R2014b the default colormap has changed from Jet to Parula.
Jet is a rainbow colormap. This type of colormap does not contain magnitude messages. This means that unless you have a colorbar or know the order of colors it is difficult to tell which color represents a higher or lower value than another color. In addition rainbow colormaps cause problems for readers with color deficiencies (8% of Caucasian men are color deficient).
The new colormap, Parula, does not show these disadvantages. It is based on changes in hue and intensity allowing a good readability for all readers, even if a plot is printed in gray scale.
The following image shows surf(peaks) with Parula being used as colormap:
While this image shows the same plot with Jet as colormap:
For further information about colormaps, please see http://pdf.aminer.org/000/240/853/designing_for_users_with_color_vision_deficiency_effective_color_combinations.pdf .
In order to set the default colormap back to Jet please use
set(groot,'DefaultFigureColormap',jet(64))
The following blog entry gives additional information about the change in default colormap <http://blogs.mathworks.com/steve/2014/10/20/a-new-colormap-for-matlab-part-2-troubles-with-rainbows/>
