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Substrate having colored indicia thereon for read-out by infrared scanning apparatus

  • US 3,933,094 A
  • Filed: 11/19/1973
  • Issued: 01/20/1976
  • Est. Priority Date: 11/19/1973
  • Status: Expired due to Term
First Claim
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1. A substrate having indicia thereon for read-out by infrared scanning apparatus and made by a method comprising the steps of providing a printing ink of a color which in combination with the substrate yields a Print Contrast Signal substantially less than 50 percent when measured in the range of 800 to 900 nanometers as determined by the equation ##EQU2## where Rw is the percentage reflectance of the unprinted substrate and Rb the percentage reflectance of the printed area, adding a pigment dispersion comprising Pigment Blue 27 -- Color Index 77510 to said ink in quantity sufficient to increase said Print Contrast Signal to at least 50 percent when measured within said range, and imprinting said indicia on said substrate with said ink after said material has been added thereto.

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