Copy prevention method

Abstract

Abstract PURPOSE:To prevent forgery of checks, etc. by a color copying machine, by using adjacently for printing, 2 colors different in spectral characteristics only in the wavelength region insensible by a photosensitive material and different only in the region low in relative luminance efficiency in the visible wavelength region. CONSTITUTION:The wavelength region sensible by a photosensitive material for color copying is generally in 560-600nm. The image formed by using 2 color materials G and H different in spectral characteristics only in the insensible wavelength region can be recognized by human eyes, but the image color-copied from this becomes similar colors and unrecognizable. On the other hand, the image formed by using 2 color materials different in spectral characteristics only in the region low in relative luminance efficiency is unrecognizable by human eyes but the image color- copied by using a photosensitive material having sensitivity to the region low in relative luminance efficiency can be clearly recognized. Combination of the above color material couples permits prevention of forgery of checks, etc. by color copying.

Inventors

• 👤 Satoshi Takeuchi
• 👤 Akira Izawa
• 👤 Yoshiaki Hida

Bibliographic Details