ColorJack provides great tools for picking and coordinating colours. The tools include:
* Color Galaxy - online colour library visualizer
* Color Sphere - visualize colour theory. It also comes in widget form
* DHTML Color Picker - pick colours in fine detail
* Color Matrix Library - colour functions - hue, saturation etc.
* Color Blindness Library - color blind simulation
* Color Conversion Library - convert to/from various colour formats
And as if that was not enough ColorJack have also created Sketchpad - a drawing application including the following tools: text, shape, spirograph, brush, calligraphy, pencil, paint-bucket and stamp.
Colors, gradients, and patterns as well as some generic drawing utilities (marquee, crop, eraser and a HSL/RGBA Color-Picker) are also included.
ColorJack could be useful for many different subject areas including web design, graphic design, art, mathematics, physics...... etc.