JP2011059060A - Computer color matching method, and computer readable recording medium recording computer color matching program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a computer color matching method for reducing the additional input amount by additionally preparing a coloring agent having a hue opposite to a shifted hue without depending on the type of the coloring agent set in the initial time in correcting the preparation amount and ratio of the coloring agent in order to make the color close to a desired color, and to provide a computer readable recording medium recording a computer color matching program. <P>SOLUTION: In this computer color matching method, color matching is performed using a white pigment, a black pigment, and two or more chromatic color pigments for any target color. Regarding color difference, this method includes a step of selecting a pigment having a hue opposite to the shifted hue in a predetermined color system as an additional pigment. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a computer color matching method and a computer readable recording medium on which a computer color matching program is recorded, and in particular, a computer color matching method and a computer color matching program capable of reducing the additional input amount of a colorant. The present invention relates to a computer-readable recording medium on which is recorded.

  In order to combine a plurality of colorants such as dyes and pigments to obtain a desired color, it is necessary to select a colorant and accurately determine the amount and ratio of the colorant. Until now, engineers have tried and error to select a colorant and obtain the amount and ratio of the colorant so as to obtain the desired color. In recent years, optical data and computers for each colorant concentration have been used. Computer color matching (hereinafter referred to as CCM) has been proposed for selecting a colorant that achieves a desired color and obtaining the blending amount and blending ratio (for example, Patent Documents 1, 2, and 3). This method is useful because color matching can be performed comparatively easily and appropriately even if not skilled in the preparation of colorants.

  The general CCM procedure is as follows. First, the spectral reflectance of the presented target color sample is measured. Subsequently, basic data corresponding to the type of the order material is specified from the basic data group of the colorant. Isomeric match or metameric match calculation is performed using the specified basic data, and the optimal combination of colorant and prescription are calculated. Test coloring is performed based on the calculated colorant and prescription. At this time, if there is a color difference between the color sample and the test color, a correction calculation is performed to calculate a corrected prescription. This operation is repeated until it falls within the predetermined allowable color difference, and if it falls within the allowable range, it is mass-produced with that formulation. In mass production processing, if the color is misaligned, the same correction calculation as the above operation is performed, and if it falls within the acceptable range, the final color management is performed.

  In CCM, samples with different concentrations and mixing ratios are prepared by changing the relative amount from the reference, and the optical density and staining density or mixing ratio are used as the basic data, according to Kubelka-Munk color mixing theory. Using the equation (Equation 1), Duncan's color mixing theory equation (Equation 2), and, if necessary, Sanderson's reflectance correction equation (Equation 3) in the algorithm, the colorant for the desired color The amount and ratio of preparation are obtained.

  Here, as a method for correcting the blending amount and blending ratio, a method of newly blending the initially set colorant or additionally blending the blended colorant is employed. Among them, an additional preparation method is used in that the prepared colorant is used without being discarded.

  For example, in Patent Document 3, it is described that four types of initially set pigments are used as additional preparation pigments, and the existing preparations are effectively used by additionally preparing the already prepared preparations. ing. In the examples, a white pigment and three kinds of chromatic pigments of red, yellow, and blue are used. However, if these three kinds of chromatic pigments are used, almost all colors can be prepared. If a small amount of pigment is added from these three types, color matching is completed.

  However, in general, when coloring with a pigment, a total of four types of colorants, a white pigment, a black pigment, and a chromatic pigment, are used. Therefore, when the color obtained by the initial formulation is in the hue direction obtained with the chromatic color of the initial colorant with respect to the target color, to correct the target color using the initial colorant In order to reduce the amount of the colorant having a relatively chromatic hue, a large amount of achromatic hue needs to be additionally prepared. For example, when the initial colorant is yellow, red, white, black, and the hue of the initial color is shifted in the orange direction with respect to the target color, yellow / red cannot be reduced for additional preparation. In order to reduce yellow and red relatively, it is necessary to add a large amount of white and black.

  In addition, usually in the case of pigment coloring, it is necessary to make the blending ratio of the colorant relative to the total blending amount, so when adding a large amount of pigment, a large amount of other agents such as binders and solvents are also added. Thus, the total amount of preparation is greatly increased. In other words, if the color obtained by the initial colorant preparation is different from the desired color, the colorant to be additionally prepared can be obtained by using only the colorant type initially set to correct the preparation ratio by the additional preparation. And the total amount of preparation may increase, leading to an increase in cost.

  Therefore, at present, only the pigment is added to prevent the total amount from being increased greatly. However, the additional correction increases the pigment ratio with respect to the total preparation amount, thereby causing problems that the fastness is lowered or that the workability is deteriorated due to changes in the viscosity and the coating amount.

Japanese Examined Patent Publication No. 6-98880 Japanese Patent Laid-Open No. 4-181129 JP-A-9-229773

  The present invention solves the above-mentioned problems, and in correcting the blending amount and ratio of the colorant so as to approximate the desired color, the hue that is shifted without being particular about the type of the colorant that was initially set. It is an object to provide a computer color matching method and a computer readable recording medium on which a computer color matching program is recorded, in which the additional input amount can be reduced by additionally blending colorants having opposite hues. .

That is, the present invention is a computer color matching method for performing color matching using a white pigment, a black pigment, and two or more chromatic pigments for an arbitrary target color,
(A) measuring a color value in a predetermined color system for a target color;
(B) measuring a color value in a predetermined color system for the actual color of a colored product colored using a white pigment, a black pigment, and two or more chromatic pigments;
(C) calculating a color difference between the color value of the target color and the color value of the actual color;
(D) inputting the type and blending amount of the colorant used in the colored product;
(E) a step of selecting, as the additional pigment, a pigment having a hue opposite to the hue shifted in the predetermined color system, and (f) an additional blending amount based on the selected additional pigment. Calculating steps,
A computer color matching method including:

The opposite hue may be in a range of a hue angle of plus or minus 60 degrees from a hue having a relation of a hue angle of 180 degrees with respect to a shifted hue direction in the a ^* b ^* hue plane of the CIELAB color system. preferable.

The present invention also provides a computer-readable record in which a program for executing computer color matching for performing color matching using a white pigment, a black pigment, and two or more chromatic pigments for an arbitrary target color is recorded. Medium, computer
(A) measuring a color value in a predetermined color system for a target color;
(B) measuring a color value in a predetermined color system for the actual color of a colored product colored using a white pigment, a black pigment, and two or more chromatic pigments;
(C) calculating a color difference between the color value of the target color and the color value of the actual color;
(D) inputting the type and blending amount of the colorant used in the colored product;
(E) a step of selecting, as the additional pigment, a pigment having a hue opposite to the hue shifted in the predetermined color system, and (f) an additional blending amount based on the selected additional pigment. Calculating steps,
The present invention relates to a computer-readable recording medium on which a program for executing is recorded.

The opposite hue may be in a range of a hue angle of plus or minus 60 degrees from a hue having a relation of a hue angle of 180 degrees with respect to a shifted hue direction in the a ^* b ^* hue plane of the CIELAB color system. preferable.

  According to the present invention, even when the initially set colorant is composed of a white pigment, a black pigment, and two kinds of chromatic pigments in correcting the amount and ratio of the colorant so as to approximate the desired color. Since the colorant having a hue opposite to the shifted hue is added without being particular about the type, the additional input amount of pigment, the total amount of preparation, and the cost can be minimized. Furthermore, since the additional amount is minimized, the influence on discoloration, metamerism, and workability can be reduced.

It is a block diagram which shows the apparatus for enforcing the computer color matching method of this invention. It is a flowchart which shows the whole procedure of this invention.

The present invention
(A) measuring a color value in a predetermined color system for a target color;
(B) measuring a color value in a predetermined color system for the actual color of a colored product colored using a white pigment, a black pigment, and two or more chromatic pigments;
(C) calculating a color difference between the color value of the target color and the color value of the actual color;
(D) inputting the type and blending amount of the colorant used in the colored product;
(E) a step of selecting, as the additional pigment, a pigment having a hue opposite to the hue shifted in the predetermined color system, and (f) an additional blending amount based on the selected additional pigment. Calculating steps,
A computer color matching method for performing color matching using a white pigment, a black pigment, and two or more chromatic pigments for an arbitrary target color, and a computer reading recording a program for executing the method It is a possible recording medium.

  Here, the object of the present invention is a colored product colored using a white pigment, a black pigment, and two or more chromatic pigments. Especially, it is particularly useful when there are two kinds of chromatic color pigments. Preferred pigment combinations are exemplified below.

White, Black, Yellow, Red White, Black, Orange, Red White, Black, Orange, Violet White, Black, Red, Violet White, Black, Violet, Blue White, Black, Violet, Turquoise White, Black, Blue, Green White・ Black ・ Blue ・ Yellow White ・ Black ・ Turquoise ・ Yellow White ・ Black ・ Turquoise ・ Orange

  FIG. 1 shows an apparatus for carrying out a computer color matching method according to the present invention. As shown in this figure, reference numeral 1 is an arithmetic processing unit such as a computer that performs calculations in accordance with programmed processing, and reference numeral 2 is a display unit such as a monitor that displays the state of calculation and calculation results. Reference numeral 3 denotes an input device such as a mouse and a keyboard for inputting various data such as a blending ratio, and reference numeral 4 denotes a storage device for storing target color data, blending ratio, basic data of colorants, arithmetic processing and arithmetic results. Reference numeral 5 denotes a spectrophotometer that acquires spectral reflectance, which is data necessary for CCM, and is a measuring device that can measure at least a visible light region of 400 nm to 700 nm.

  FIG. 2 is a flowchart showing an overall procedure of processing in the present invention. According to FIG. 2, the procedure for obtaining the additional blending amount when the colored material is not allowed in the present invention will be described.

(Procedure 1) An environment where a spectrophotometer, an arithmetic processing device such as a computer, a display device such as a monitor, etc. can be used is set.
(Procedure 2) A target color, which is a desired color, is measured by the spectrophotometer 5 and the color value is stored in the storage device 4. The color value referred to here is not limited to the color system values such as XYZ and L ^* a ^* b ^* based on the spectral reflectance, but covers all color values.
(Procedure 3) The object to be colored is colored using a plurality of designated colorants at a determined blending amount and blending ratio.

(Procedure 4) The colored product colored in the procedure 3 is measured by the spectrophotometer 5 and the color value is stored in the storage device 4.
(Procedure 5) The color difference is calculated from two color values obtained from the result of measuring the target color and the colored product. The color difference is not limited to ΔX, ΔY, ΔZ of the XYZ color system, the color difference of the Munsell color system, the ΔL ^* , Δa ^* , Δb ^* of the CIELAB color system, or any color such as ΔE * _ab , ΔEcmc, CIEDE2000, etc. All color differences of the system are targeted.

(Procedure 6) It is determined whether the color difference calculated in Procedure 5 is within an allowable range, and the determined result is displayed on the display device 2. The allowable value is arbitrarily set separately. If it is determined in step 6 that the color is acceptable, it can be determined that the color is close to a range acceptable for the desired color, and a series of color matching operations is completed (procedure 10). If it is determined in step 6 that the color is not acceptable, it is necessary to correct the color of the colored object.
(Procedure 7) The type of the colorant and the blending amount of each colorant of the colored material created in Procedure 3 are input from the input device 3. This procedure is necessary in order to calculate the blending amounts and blending ratios of the various input colorants from the input blending amounts of the various colorants in the following procedure 9.

(Procedure 8) A colorant to be added is selected. Here, in consideration of the difference in hue between the colored product obtained in step 5 and the target color, for example, a colorant having a hue direction opposite to the currently shifted hue direction in the CIELAB color system, Select as a colorant to be added in addition to the colorant selected in advance. The color system used here is not limited to the CIELAB color system, and may be a color system such as an XYZ color system or a Munsell color system. The hue direction opposite to the shifted hue direction is, for example, plus or minus 60 from the hue having a hue angle relationship of 180 ° with the shifted hue direction in the a ^* b ^* hue plane of the CIELAB color system. The hue angle can be in the range of °. It is particularly preferable that the angle is plus or minus 30 °. If a colorant that exceeds the range of the hue angle of plus or minus 60 ° is selected, the amount of additional input tends to increase. In the Munsell color system, a hue having a complementary color relationship may be used.

(Procedure 9) Based on the basic data of the colorant stored in the storage device 4, the color value of the target color, and the color value of the colored object, an arithmetic process is performed according to a color matching algorithm so as to correct the color difference. The additional preparation amount is calculated by the apparatus 1. The calculated result is displayed on the display device 2 and the metamerism index with the designated light source is also displayed. Here, the cost of additional input, the predicted robustness, and the like may be displayed. The designated light source serving as the second light source at this time is not limited to one, and an average value of metamerism indexes for a plurality of light sources may be applied. Furthermore, the calculated result can be stored in the storage device 4 and used for the correction calculation of the next preparation amount. The metamerism index is used for evaluating metamerism. Further, as a method for calculating the metamerism index, a formula such as JIS Z 8719 Conditional Color Index or DIN 6172 may be used.

  The color matching algorithm here refers to the above-mentioned Kubelka-Munk theory (Equation 1), Duncan's color mixing theory (Equation 2), and basic data of colorants, and the formulation amount is determined using the Newton-Raphson method or the Allen method. It is to seek. The CCM calculation method may be either a fixed number or two constant theory, and the convergence condition may be either a metameric match or an isomeric match.

  In addition, in the calculation here, the amount of the colorant actually prepared and the amount of the other agent are input, and the amount of the liquid prepared for the laboratory test is input from the prepared agent. The amount of the colorant remaining after the test can be determined, and a more accurate additional preparation amount can be calculated.

  Further, in the measurement of the target color in the procedure 2, the target color may be stored in the storage device 4 and the color data of the target color may be called. You may call and use the data stored in

  The method for calculating the tristimulus values XYZ can be calculated from the following calculation formula using the spectral reflectance.

Further, the L ^* a ^* b ^* value can be calculated from the obtained tristimulus values XYZ by the following calculation formula.

  Hereinafter, the present invention will be described specifically by way of examples.

Example 1
Corrections were made by the CCM method of the present invention for the colored products colored using white, black, yellow and red as pigments. The blending amount of the colorant, the target color, and the color value of the actual color are as shown in Table 1. The color difference between the initially prepared colored product and the target color was ΔE * _ab : 0.93. As a result of the color difference determination, the color difference was rejected. In the L ^* a ^* b ^* color system, the hue angle at which the initial blend color deviates from the target color was Δh °: 79.4 °.

Further, the specific CIELAB color system hue angle of each chromatic pigment used was as follows.
Yellow: 95.7 °
Orange: 49.7 °
Red: 27.9 °
Violet: 326.3 °
Blue: 289.8 °
Turquoise: 214.9 °
Green: 187.8 °

  Here, the chromatic pigment closest to the opposite hue (259.4 °) of the hue angle of 79.4 °, which is shifted from the initial blend color with respect to the target color, is a blue pigment having a hue angle of 289.8 °. Yes, this was selected as a colorant to be additionally formulated. As a result, the additional preparation amount of the blue pigment was 5.51 g, and the total additional preparation amount was 173.34 g. Compared with the comparative example mentioned later, the additional amount of the coloring agent was considerably reduced.

Comparative Example 1
The colored product colored in the same manner as in Example 1 was additionally prepared by a conventional method. That is, since the hue is greatly shifted in the yellowish direction, black was added to relatively reduce the influence of yellow. Furthermore, a large amount of white was added for density adjustment. As a result, the total amount of pigment added was 505.82 g.

Comparative Examples 2-5
The orange, violet, turquoise, and green pigments were additionally modified as additional pigments for the colored products that were colored in the same manner as in Example 1. The results are shown in Table 3.

DESCRIPTION OF SYMBOLS 1 Computation device 2 Display device 3 Input device 4 Storage device 5 Spectrophotometer

Claims (4)

A computer color matching method for performing color matching using a white pigment, a black pigment, and two or more chromatic pigments for an arbitrary target color,
(A) measuring a color value in a predetermined color system for a target color;
(B) measuring a color value in a predetermined color system for the actual color of a colored product colored using a white pigment, a black pigment, and two or more chromatic pigments;
(C) calculating a color difference between the color value of the target color and the color value of the actual color;
(D) inputting the type and blending amount of the colorant used in the colored product;
(E) a step of selecting, as the additional pigment, a pigment having a hue opposite to the hue shifted in the predetermined color system, and (f) an additional blending amount based on the selected additional pigment. Calculating steps,
Including computer color matching method. The opposite hue is in a range of a hue angle of plus or minus 60 degrees from a hue having a relation of a hue angle of 180 degrees with a shifted hue direction in the a ^* b ^* hue plane of the CIELAB color system. The computer color matching method according to 1. A computer-readable recording medium recording a program for executing computer color matching for performing color matching using a white pigment, a black pigment, and two or more chromatic pigments for an arbitrary target color, In addition,
(A) measuring a color value in a predetermined color system for a target color;
(B) measuring a color value in a predetermined color system for the actual color of a colored product colored using a white pigment, a black pigment, and two or more chromatic pigments;
(C) calculating a color difference between the color value of the target color and the color value of the actual color;
(D) inputting the type and blending amount of the colorant used in the colored product;
(E) a step of selecting, as the additional pigment, a pigment having a hue opposite to the hue shifted in the predetermined color system, and (f) an additional blending amount based on the selected additional pigment. Calculating steps,
The computer-readable recording medium which recorded the program for performing this. The opposite hue is in a range of a hue angle of plus or minus 60 degrees from a hue having a relation of a hue angle of 180 degrees with a shifted hue direction in the a ^* b ^* hue plane of the CIELAB color system. 3. A computer-readable recording medium according to 3.

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