Color is a Ruby library to provide basic RGB, CMYK, HSL, and other colourspace manipulation support to applications that require it. It also provides 152 named RGB colours (184 with spelling variations) that are commonly supported in HTML, SVG, and X11 applications. A technique for generating monochromatic contrasting palettes is also included. The capabilities of the Color library are limited to pure mathematical manipulation of the colours based on colour theory without reference to colour profiles (such as sRGB or Adobe RGB). For most purposes, when working with the RGB and HSL colours, this won't matter. However, some colour models (like CIE L*a*b*) are not supported because Color does not yet support colour profiles, giving no meaningful way to convert colours in absolute colour spaces (like L*a*b*, XYZ) to non-absolute colour spaces (like RGB). Color version 1.5.1 is mostly a maintenance release, fixing some bugs that may have been introduced with the previous release on Ruby 1.8.7. New features include an experimental contrast comparison method for RGB colours (found in lib/color/rgb/contrast.rb) provided by Dave Heitzman, and methods suggested by Thomas Sawyer based on the Spectrum library. Barring bugs introduced in this release, this will be the last version of color that supports Ruby 1.8, so make sure that your gem specification is set properly, to <tt>~> 1.5</tt> if that matters for your application.