A few points here. What you supplied was a bitmapped file. A bitmap file is made up of dots and not lines. Whenever you change the size of a bitmapped file, there is a real likelihood of the image changing and producing what are called artifacts. The artwork may have worked better as a vector based file. The second issue is that most printers work in some variation of cyan, magenta, yellow and black ink. A purple would have elements of each of those in it. To achieve various colors they print halftone dots with the intent of fooling the eye. If the artwork had been vector based, the halftone dots may have been smaller but still present. The light silver would have printed better with a silver foil which is only available with a handful of printers, the ALPS being the most common.