While working for image processing software, color conversion (or color-space conversion) is the very fundamental skill we have to face first. With deep understanding of color science, we can guarantee the color of image pixel is not shifted. Also, some algorithms we are using may work best in some color space than others. Besides that, digital photo developing is quite popular now, color monitor/printer profiling is also a topic we need to know so we can guarantee the color perception value are matched among all involved parties.
There are very good online material for these topics, for example, Bruce Lindbloom has a very good Bruce Lindbloom for all these information.
We port our color conversion algorithm (in native C++) to Android platform as an app, Color Calculator. Based on CIE color specification, several tools are developed to provide color space conversion among XYZ, xyz, LAB, HSI, HSV, color temperature, etc. Also, this app also provides real-time color sampling by live camera view, or by analyzing a photo. Users can also organize samples color in a color-palette organizer. Last but not least, for every color, we also profile Adobe Kuller-like function to provide harmony color palette, which is good for designer or artist.