The present disclosure relates to signal processing such as image processing, signal encoding, digital watermarking and data hiding. Technology includes a method comprising: capturing imagery corresponding to a printed object with a red illumination scanner, the red illumination scanner having a wavelength at or around 660 nm, said scanning yielding scan data, wherein the printed object includes a process color printed thereon through an offset or flexo printing press, the process color including a narrow-band absorption material that has a peak absorbance at or around 660 nm, the process color printed in a manner to convey an encoded plural-bit message, the encoded plural-bit message corresponding to a GTIN number; analyzing the imagery with one or more programmed multi-core processors to decode the encoded plural bit message, said analyzing yielding the GTIN number; and providing the GTIN number as an output. Of course other combinations and technology is also provided.