Disclosed is an anti-counterfeiting printed material including: a background part for analyzing a distribution of Cyan Magenta Yellow Black (C/M/Y/K) after performing first color separation of an original image into C/M/Y/K, and printing the original image as C/M/Y/K lines each having an included angle preset according to each distribution; and a latent image part formed in a first region of the background part, and printed with the number of C/M/Y/K lines in a ratio different from the number of C/M/Y/K lines of the background part according to each distribution by performing secondary color separation, into C/M/Y/K, of a second region spaced apart from the first region by a preset distance.

In an example method, a first dot pattern of shadow dots and second dot pattern of highlight dots is generated. The first dot pattern and second dot pattern include information to be encoded across the image. The first dot pattern and the second dot pattern are mapped to a corresponding subset of the greyscale source pixels, the greyscale source pixels corresponding to an image to be printed. A value of a greyscale pixel in the subset of the greyscale source pixels is modified based on a predetermined threshold pixel value. The value of the greyscale pixel is set to a highlight dot value in response to detecting that the predetermined threshold pixel value is exceeded or set to a shadow dot value in response to detecting that the predetermined threshold value is not exceeded. The image including the subset of pixels with modified values is printed.

A method for producing security elements in an image which are not visible to the human eye and which cannot be copied, in particular for checking the authenticity of images. The image is imaged by means of a halftone, the halftone consisting of individual image dots arranged adjacent to each other. This is characterized in that at least one field having a random geometric shape or freeform is defined in the image/the halftone. By means of manipulation of image dots in the field and/or by means of manipulation of the entire field, an encrypted information that cannot be copied is stored for comparison with at least one database and the serial number is displayed by means of contours formed in the halftone.

Digital watermarking is adapted for the variable data printing. A reference signal serves as a proxy for optimizing the embedding a watermark in a host image to be printed. Using the reference signal, embedding parameters are generated, which are a function of constraints such as visual quality and robustness of the machine readable data. Adjustments needed to embed a unique payload in each printed piece are generated using the embedding parameters. These adjustments are stored in a manner that enables them to be efficiently obtained and applied within the raster image processor or press during operation of the press. Various other methods, system configurations and applications are also detailed.

Variable data printing workflows are enhanced for use with content that includes 2D code patterns, such as digital watermark data. One arrangement includes applying a filter to a content stream within a PDF document to extract both first variable pattern data for a first watermark pattern and second variable pattern data for a second watermark pattern. A first composite watermark pattern is then defined based on the extracted first variable watermark pattern data in conjunction with static watermark pattern data, and a second composite watermark pattern is defined based on the extracted second variable watermark pattern data in conjunction with the static watermark pattern data. A variety of other features and arrangements are also detailed.

In an example method, a first dot pattern of shadow dots and second dot pattern of highlight dots is generated. The first dot pattern and second dot pattern include information to be encoded across the image. The first dot pattern and the second dot pattern are mapped to a corresponding subset of the greyscale source pixels, the greyscale source pixels corresponding to an image to be printed. A value of a greyscale pixel in the subset of the greyscale source pixels is modified based on a predetermined threshold pixel value. The value of the greyscale pixel is set to a highlight dot value in response to detecting that the predetermined threshold pixel value is exceeded or set to a shadow dot value in response to detecting that the predetermined threshold value is not exceeded. The image including the subset of pixels with modified values is printed.

A data-bearing medium is disclosed. The data-bearing medium includes a section of cells having a set of opposite-shifted clusters. The cells include a combination of opposite shifts of the set of opposite-shifted clusters, which represent a single value.

A method for producing security elements in an image which are not visible to the human eye and which cannot be copied, in particular for checking the authenticity of images. The image is imaged by means of a halftone, the halftone consisting of individual image dots arranged adjacent to each other. This is characterized in that at least one field having a random geometric shape or freeform is defined in the image/the halftone. By means of manipulation of image dots in the field and/or by means of manipulation of the entire field, an encrypted information that cannot be copied is stored for comparison with at least one database and the serial number is displayed by means of contours formed in the halftone.

A method for checking the authenticity of products, by checking an image (A) of a product. The proof of authenticity is not visible to the human eye and cannot be copied. This is characterized in that a code stored in a halftone image by manipulation of dots and/or a manipulated field bounded in the halftone image can be read by means of an optical device and compared with a retrievable value in at least one database. In at least one field (F1 to F5) a part of a serial number is determined which describes the structure of the serial number and a hash function used for transmitting the serial number to the database, and this is also characterized in that the serial number is subsequently assembled and encrypted with the corresponding hash function.

In an example method, a set of source pixels corresponding to an image to be printed and a dot pattern of pixels including information to be encoded across the image are received. The dot pattern of pixels is mapped to a corresponding subset of the source pixels. A value of a clipping channel color in the subset of the source pixels is modified based on an original value of the clipping channel color for each pixel in the subset. The clipping channel color is used to detect the dot pattern of pixels. The image including the subset of pixels with modified clipping channel colors is printed.