The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 27, 1988
Filed:
Sep. 16, 1987
Peter W Stansfield, Hertfordshire, GB;
Alastair Reed, Bedfordshire, GB;
Crosfield Electronics Limited, London, GB;
Abstract
In color printing it is customary to print images in a combination cyan, magneta, and yellow printing inks. However, it is sometimes required in the printing of the final image, to include an ink of a special color, for example a brown ink, which cannot be reproduced by combining cyan, magenta and yellow inks. The present invention is concerned with the preparation of a special color printer for a special printing ink. According to the invention sets of values (C.sub.ROP, M.sub.ROP, Y.sub.ROP, K.sub.ROP) defining the characteristic elements of curves for cyan, magenta, yellow, and black, which curves together correspond to a range of values for the overprinted colored separation, are stored. For each picture element, a combination of color component values for cyan, magenta, yellow and black (C,M,Y,K) are derived and compared with different sets of values (C.sub.ROP, M.sub.ROP, Y.sub.ROP, K.sub.ROP) derived from the stored curve elements, each set corresponding to a different value of the overprinted special color separation (R.sub.OP). A value is selected for the desired special color separation for which each of the stored values of the related set (C.sub.ROP, M.sub.ROP, Y.sub.ROP, K.sub.ROP) is not greater than the corresponding value (C,M,Y,K) derived from the picture element of the original. The stored values (C.sub.ROP, M.sub.ROP, Y.sub.ROP, K.sub.ROP) are then subtracted from the corresponding values (C,M,Y,K) to get residual values (C',M',Y', K'). The residual values (C',M',Y',K') are then modified to give a corresponding set of modified values (C',M',Y',K') and a special color separation value (R) is selected which is overprinted to constitute the selected overprinted special color.