Making modern film or digital copies of Autochromes introduces other problems, because a color system based on red, green, and blue is used to copy an image that exists within the red-orange, green, and blue-violet system, providing further opportunities for color degradation. Vintage reproductions of Autochromes in old books and magazines have often been noticeably hand-adjusted by the photoengravers in an effort to compensate for some of the difficulties of reproduction, and as a result they sometimes look more like hand-colored photographs than "natural color" ones. In short, it is very difficult to form an accurate impression of the appearance of any Autochrome image without seeing the original "in person" and correctly illuminated.