Abstract: Apparatus and method for storing large amount of digital data into the color halftone micro-dots generated by high resolution color laser or ink jet printers or lithography on a substrate, such as paper. A data cell composed of color halftone micro-dots is encoded with multi-bit digital binary data. The size of the data cell is determined by the resolution of the color printer and the color scanner, the density of the cyan, yellow, magenta and black inks and the reflectance of the red, green and blue lights, in order to meet the requirement of decoding the multi-bit binary data with enough noise immunity. Collections of data cells in a two-dimensional matrix forms a data block. The data block is enclosed with an exterior data cell border with pre-determined data pattern and is used to determine the spacing of the data cell, the orientation of the data block and reflectance of the data cells during scanning and data reconstruction.