Patent ID: 7177476

Claim:
A method of preserving data about a document that has been received in electronic form, the method comprising: (a) encoding data about the document in a monochrome medium by: (a1) converting the document to a rasterized image in which each pixel is assigned a raster value; (a2) for each pixel: (a2a) assigning a data word having a first bit depth, said data word comprising a first data field and a second data field; (a2b) encoding a first component of said raster value into said first data field; (a2c) encoding a second data value into said second data field; (a2d) generating a grayscale data value comprising said first data field and said second data field; and, (a2e) forming, onto the monochrome medium, a grayscale pixel conditioned by said grayscale data value; (b) responding to a request for said first component of said raster value for each said grayscale pixel, by: (b1) scanning said grayscale pixel to obtain a monochrome density value having a second bit depth; (b2) decomposing said monochrome density value to obtain said first data field; and (b3) decoding said first data field to obtain said first component of said raster value.