In an example, a processor-readable medium stores code representing instructions that when executed by a processor cause the processor to receive an image, a graphical element, and embedding information. The processor further encodes a binary value representing the embedding information into the graphical element. The zeros and ones from the binary value are distinguished in the graphical element by a difference in luminance values applied to segments of the graphical element. The processor further combines the encoded graphical element with the image without altering the image.