Images: EFF cracks printer tracking code

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  • printer code

    printer code

    Sleuths from the Electronic Frontier Foundation have analyzed a tracking code that's printed on every page produced by a Xerox Docucolor 12 laser printer. Many printer manufacturers embed code to give the Secret Service a tool to track counterfeiters, although it can easily be used for other purposes.

    The tracking code is printed in tiny yellow dots which are generally not visibile by the naked eye under white light. Under blue light and magnified, the yellow dots appear black.

    Caption by: Bill Detwiler

  • yellow dots

    yellow dots

    This is what the dots look like under 60x magnification photographed by a Digital Blue QX5 computer microscope.

    Caption by: Bill Detwiler

  • 21819.jpg

    Here is a magnified image of the code as it appears on a printed document.

    Caption by: Bill Detwiler

  • show through

    show through

    The ink for the code will show through print.

    Caption by: Bill Detwiler

  • enhancing the dots

    enhancing the dots

    This computer graphics overlay is not to scale but it allows easier analysis of the pattern.

    Caption by: Bill Detwiler

  • connecting the dots

    connecting the dots

    Here's what the dots reveal: the date, time and printer's serial number on every printed page.

    Caption by: Bill Detwiler

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show through

The ink for the code will show through print.

Caption by: Bill Detwiler

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