| 摘要 |
<p>Printing consisting of a first image formed by a photographic or colour-printed reproduction with the appearance of an image with normal density and colour to be viewed by means of reflected light, and a second identical image arranged behind and in exact register with the first, but underexposed or less dense compared with the first image. When a photographic process is used, the images may be formed in the front part and the rear part of a single transparent substrate.</p> |
