A modular device includes base and color sensing portions. The color sensing portion has a face, a controlled light source offset from the face to define an interior, the face configured to engage a target surface about a perimeter of the device housing wherein ambient light is restricted from entering the interior. A color sensor receives light reflected from the target surface and generates output signals representative of a surface color. The base portion communicates with the color sensor and a user device having a hosted program which generates a user interface enabling users to provide control input for the color sensor. The program further receives the output signals from the color sensing device and displays a first image of the detected color, and displays a second image of a user-selected color beside the first image. Color data values are further displayed corresponding to the difference between displayed colors.