| 摘要 |
PURPOSE:To print a concealed image artificially by a four-color printing instead of a conventional five-color printing, by a method wherein, in a portion to be a concealed picture pattern, a light color among colors of the multi-color printing is substituted to be overlapped as dots of the same color and added to dots of the general picture pattern to be overlapped. CONSTITUTION:A general picture pattern is decomposed into four colors to be continuous films of Indigo A, Red A', Yellow A'', and Black A'''. On the other hand, for example, Light-indigo B to be a concealed image is prepared, and the color A of the general picture pattern and the color B are printed to a film to be overlapped as dots of the additive mixture of the colors A and B so as to be exposed to different degrees (the color A is exposed to a high degree and the color B to a low degree). Similarly, the mixtures of the color B to the colors A', A'', and A''' are respectively printed to films. Original plates G, G', G'', and G''' are made by using the added film original plates through screens S, S', S'', and S''', respectively. By using a multi-color printer with the original plates of four colors G, G', G'', and G''', a concealed image of the general picture pattern A incorporating a concealed picture pattern B can be printed. |
