Method of obtaining half-tone dot percents necessary for reproducing colors

Claim 2

In a method of obtaining half-tone dot percents of color separations necessary for reproducing colors assigned by a color specimen, a method of obtaining half-tone dot percents necessary for reproduction of colors, the steps comprising: storing within a memory means a conversion table of color information - half-tone dot percent representing the corresponding relation between color information and a combination of half-tone dot percents corresponding to said color information; optically measuring said color specimen to detect color information of colors to be printed; successively operating to compare color information obtained from said color specimen with color information of said table and selecting color information which is most approximate to the color information obtained from said color specimen out of the color information of said table; selecting the half-tone dot percent corresponding to the selected color information from said table; and using the extracted half-tone dot percent as a half-tone dot percent of the color separation necessary for reproducing colors assigned by the color specimen.

Claim 3

A method as claimed in claim 1, wherein said color information is color density or chromaticity.

Claim 4

A method as claimed in claim 1, wherein said color information is color density, said color density being represented by a combination of four color densities obtained through a red filter, a green filter, a blue filter and an amber filter or an ND filter.

Claim 5

A method as claimed in claim 1, wherein said color information is color density, said color density being represented by a combination of three color densities obtained through a red filter, a green filter and a blue filter.

Claim 6

A method as claimed in claim 1, wherein said color separations comprise a combination of color separations of cyan, magenta, yellow and black.

Claim 7

A method as claimed in claim 1, wherein a plurality of printed matters printed by use of color separations having a predetermined combination of half-tone dot percents are optically measured to obtain color information, said half-tone dot percents are inputted from a key-board, and said conversion table of color information - half-tone dot percent is stored in the memory means.

Claim 8

A method as claimed in claim 1, wherein when actual printing is performed on a printing condition different from the printing condition on which printed matters used when the conversion table of color information - half-tone dot percent was prepared were printed -- different printing papers, different tone reproducing curves and different dot 100% densities, correction is made to remove a difference between said two different conditions with respect to color information obtained from said color specimen.

Claim 9

A method as claimed in claim 1, wherein said operation to compare is performed by calculation of distance between the color information of the color specimen and the color information of the conversion table of color information - half-tone dot percent, and color information in said table in which said distance is the smallest is made most approximate to the color information of the color specimen.

Claim 10

In a method of obtaining half-tone dot percents of color separations necessary for reproducing colors assigned by a color specimen, a method of obtaining half-tone dot percents necessary for reproduction of colors, the steps comprising: storing within a memory means a conversion table of color information - half-tone dot percent representing the corresponding relation between color information and a combination of half-tone dot percents corresponding to said color information; optically measuring said color specimen to detect color information of colors to be printed; successively operating to compare color information obtained from said color specimen with color information of said table and selecting color information which is most approximate to the color information obtained from said color specimen out of the color information of said table; whereby if the color information of the color specimen and the selected color information are not in coincidence, said table is interpolated to obtain a half-tone dot percent corresponding to more approximate color information, whereas if they are in coincidence, the half-tone dot percent corresponding to said selected color information is selected from said table, and the obtained half-tone dot percent is used as half-tone dot percents of color separations necessary for reproducing colors assigned by the color specimen.

Claim 11

In a method of obtaining half-tone dot percents of color separations necessary for reproducing colors assigned by a color specimen, a method of obtaining half-tone dot percents necessary for reproduction of colors, the steps comprising: storing within a memory means a conversion table of color information - half-tone dot percent representing the corresponding relation between color information and a combination of half-tone dot percents corresponding to said color information; optically measuring said color specimen to detect color information of colors to be printed; successively operating to compare color information obtained from said color specimen with color information of said table and selecting color information which is most approximate to the color information obtained from said color specimen out of the color information of said table; whereby if the color information of the color specimen and the selected color information are not in coincidence, said table is interpolated to obtain a half-tone dot percent corresponding to more approximate color information, whereas if they are in coincidence, the half-tone dot percent corresponding to said selected color information is selected from said table, and the obtained half-tone dot percent is used as half-tone dot percents of color separations necessary for reproducing colors assigned by the color specimen.

Claim 12

A method as claimed in claim 9, wherein said color information is color density or chromaticity.

Claim 13

A method as claimed in claim 9, wherein said color information is color density, said color density being represented by a combination of four color densities obtained through a red filter, a green filter, a blue filter and an amber filter or an DN filter.

Claim 14

A method as claimed in claim 9, wherein said color information is color density, said color density being represented by a combination of three color densities obtained through a red filter, a green filter and a blue filter.

Claim 15

A method as claimed in claim 9, wherein said color separations comprise a combination of color separations of cyan, magenta, yellow and black.

Claim 16

A method as claimed in claim 9, wherein a plurality of printed matters printed by use of color separations having a predetermined combination of half-tone dot percents are optically measured to obtain color information, said half-tone dot percents are inputted from a key-board, and said conversion table of color information - half-tone dot percent is stored in the memory means.

Claim 17

A method as claimed in claim 9, wherein when actual printing is performed on a printing condition different from the printing condition on which printed matters used when the conversion table of color information - half-tone dot percent was prepared were printed -- different printing papers, different tone reproducing curves and different dot 100% densities correction is made to remove a difference between said two different conditions with respect to color information obtained from said color specimen.

Claim 18

A method as claimed in claim 9, wherein said operation to compare is performed by calculation of distance between the color information of the color specimen and the color information of the conversion table of color information - half-tone dot percent, and color information in said table in which said distance is the smallest is made most approximate to the color information of the color specimen.

Claim 19

A method as claimed in claim 9, wherein said interpolation is performed between the half-tone dot percent corresponding to the selected color information which is to be most approximate and a half-tone dot percent present around and in the vicinity thereof to obtain a finer half-tone dot percent and color information corresponding thereto, and distance calculation is applied between these color information and color information of color specimen to extract a half-tone dot percent corresponding to color information which is most approximate.

Claim 20

A method as claimed in claim 9, wherein standard vectors represented by the selected color information which is most approximate and color information of a plurality of neighbouring half-tone dot.percents are used to represent a vector from said selected color information to color information of color specimen, and said interpolation is effected by obtaining said vector.

Claim 21

In a method of obtaining half-tone dot percents of color separations necessary for reproducing colors assigned by a color specimen, a method of obtaining half-tone dot percents necessary for reproduction of colors, the steps comprising: storing within a memory means a conversion table of color information - half-tone dot percent representing the corresponding relation between color information and a combination of half-tone dot percents corresponding to said color information; optically measuring said color specimen to detect color information of colors to be printed; successively operating to compare color information obtained from said color specimen with color information of said table and selecting color information which is most approximate to the color information obtained from said color specimen out of the color information of said table; whereby the half-tone dot percent corresponding to said selected color information is obtained from said table, and judgement is made if a value of 0% or 100% is included in said obtained half-tone dot percent, and if included, a half-tone dot percent of the value below 0% or above 100% and color information corresponding to said half-tone dot percent are produced in accordance with said table, and the expanded color information and half-tone dot percent are subjected to interpolation calculation to obtain a half-tone dot percent corresponding to color information most approximate to the color information of color specimen, whereas if not included, said table is interpolated to obtain a half-tone dot percent corresponding to more approximate color information, and the obtained half-tone dot percent is used as a half-tone dot percent of color separation necessary for reproducing colors assigned by the color specimen.

Claim 22

In a method of obtaining half-tone dot percents of color separations necessary for reproducing colors assigned by a color specimen, a method of obtaining half-tone dot percents necessary for reproduction of colors, the steps comprising: storing within a memory means a conversion table of color information - half-tone dot percent representing the corresponding relation between color information and a combination of half-tone dot percents corresponding to said color information; optically measuring said color specimen to detect color information of colors to be printed; successively operating to compare color information obtained from said color specimen with color information of said table and selecting color information which is most approximate to the color information obtained from said color specimen out of the color information of said table; whereby the half-tone dot percent corresponding to said selected color information is obtained from said table, and judgement is made if a value of 0% or 100% is included in said obtained half-tone dot percent, and if included, a half-tone dot percent of the value below 0% or above 100% and color information corresponding to said half-tone dot percent are produced in accordance with said table, and the expanded color information and half-tone dot percent are subjected to interpolation calculation to obtain a half-tone dot percent corresponding to color information most approximate to the color information of color specimen, whereas if not included, said table is interpolated to obtain a half-tone dot percent corresponding to more approximate color information, and the obtained half-tone dot percent is used as a half-tone dot percent of color separation necessary for reproducing colors assigned by the color specimen.

Claim 23

A method as claimed in claim 19, wherein said color information is color density or chromaticity.

Claim 24

A method as claimed in claim 19, wherein said color information is color density, said color density being represented by a combination of four color densities obtained through a red filter, a green filter, a blue filter and an amber filter or an ND filter.

Claim 25

A method as claimed in claim 19, wherein said color information is color density, said color density being represented by a combination of three color densities obtained through a red filter, a green filter and a blue filter.

Claim 26

A method as claimed in claim 19, wherein said color separations comprise a combination of color separations of cyan, magenta, yellow and black.

Claim 27

A method as claimed in claim 19, wherein a plurality of printed matters printed by use of color separations having a predetermined combination of half-tone dot percents are optically measured to obtain color information, said half-tone dot percents are inputted from a key-board, and said conversion table of color information - half-tone dot percent is stored in the memory means.

Claim 28

A method as claimed in claim 19, wherein when actual printing is performed on.a printing condition different from the printing condition on which printed matters used when the conversion table of color information - half-tone dot percent was prepared were printed -- different printing papers, different tone reproducing curves and different dot 100% densities, correction is made to remove a difference between said two different conditions with respect to color information obtained from said color specimen.

Claim 29

A method as claimed in claim 19, wherein said operation to compare is performed by calculation of distance between the color information of the color specimen and the color information of the conversion table of color information - half-tone dot percent, and color information in said table in which said distance is the smallest is made most approximate to the color information of the color specimen.

Claim 30

A method as claimed in claim 19, wherein said interpolation is performed between the half-tone dot percent corresponding to the selected color information which is to be most approximate and a half-tone dot percent present around and in the vicinity thereof to obtain a finer half-tone dot percent and color information corresponding thereto, and distance calculation is applied between these color information and color information of color specimen to extract a half-tone dot percent corresponding to color information which is most approximate.

Claim 31

A method as claimed in claim 19, wherein standard vectors represented by the selected color information which is most approximate and color information of a plurality of neighbouring half-tone dot percents are used to represent a vector from said selected color information to color information of color specimen, and said interpolation is effected by obtaining said vector.

Claim 32

A method as claimed in claim 19, wherein where the half-tone percent obtained by interpolation calculation including said expanded color information and half-tone dot percent is in coincidence with a newly produced half-tone dot percent, an expanded half-tone dot percent and color information corresponding thereto are further produced, and said interpolation calculation is repeatedly effected to obtain a half-tone dot percent.

Claim 33

A method as claimed in claim 19 or 29, wherein color information in said half-tone dot percent of value below 0% or above 100% is obtained in accordance with color information of half-tone dot percent immediately before 0% or immediately before exceeding 100% of said table.