xcolor is a jQuery plugin which allows you to perform many different manipulations on colors.

First of all, it can parse and convert colors between different formats with methods like getRGB(), getHSV() or getHEX().

Another powerful feature is extracting or combining colors (like red + blue would result in purple).

Also, it can generate complementary colors, lighten/darken them, find analogous/monochromatic colors of an item and much more.

The plugin comes with other functions where the most interesting one is: isReadable which performs a readability test for a text on a given background.

Tip: To perform the same actions on the server-side, the author also has a PHP class with very similar features.

A web designer usually starts with a color and needs the variations of that color for hover, borders, gradients, etc. while designing/styling an element.

In order to be stable for the overall of the design, while choosing color variants, picking them from the same levels is a much better way compared to just guessing using the color picker of our image editing software.

0to255 is a simple-yet-effective web-based color finder which is specially created for web designers to make this process easier.

After picking the color you want to start with, the tool provides you a range of colors from black to white using an interval optimized for web design.

And, just click the variation you want to use and the hex code is automatically copied to your clipboard.

Designers, who wonder the RGB of any color that is around their mouse can get the results instantly.

Small utility named Pixie, runs on your system tray, you can call it with a click and it will show you HEX, RGB, CMYK & HSV values of any pixel you’re pointing.

Many designers take a screen capture, run their favorite image editing software like Photoshop, Fireworks and paste the capture to the image editing software to get the image color values. With Pixie, no need for these steps.

An extra feature of Pixie is, it shows the x y position of the mouse pointer.