JP2004291267A - Color material amount distribution device and method for forming color material amount distribution definition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To appropriately obtain a color material amount for reproducing a desired relation between a gradation value and a color density. <P>SOLUTION: A color material amount distribution device passes a color material amount distribution definition which defines a corresponding relation between the color material amount of each of a plurality of color materials having the same hue and different concentrations each other, and the gradation value expressing an image through a chart output process and a density-color material amount relation acquisition process by an output device for outputting the image with the use of the plurality of color materials. In the chart output process, a chart is outputted wherein a plurality of patches of different combinations of the color material amounts of the plurality of color materials are arranged. In the density-color material amount relation acquisition process, a corresponding relation between the color material amount combination and a density is obtained by measuring the patch of the chart outputted at the chart output process. The corresponding relation between the color material amount and the gradation value is formed on the basis of the desired relation between the gradation value and density, and the corresponding relation between the density and color material amount obtained at the density-color material amount relation acquisition process through a color material amount-gradation value relation derivation process of deriving so that a total color material amount is accommodated within an upper limit for the total color material amount of the plurality of color materials. The color material amount is obtained with the use of the color material amount distribution definition. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a color material amount distribution device that determines a color material amount for each of a plurality of color materials, and a color material amount distribution definition creation method that creates a color material amount distribution definition that defines the color material amounts of each of a plurality of color materials.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, output devices that output an image using a plurality of colors are known, such as an ink jet printer and an electrophotographic printer. Such an output device is generally connected to a personal computer or the like that functions as a color material amount distribution device for obtaining the color material amount of each color material, and outputs an image using an amount of color material designated by the personal computer or the like. To do.
[0003]
The color material amount distribution device calculates the color material amount of each color material based on the image data representing the image with the gradation value of each color, and outputs the color material amount so that the color of the image is appropriate. To instruct.
[0004]
By the way, in order to ensure a sufficient color reproduction range by the output device, it is common to use a color material having a sufficiently high density. Further, as an output method of the output device, a method in which dots of the color material are applied in a number corresponding to the amount of the color material is often used. For this reason, when a highlight image with a light hue is output, a rough impression due to the graininess of the spots of the color material, which is so-called roughness, tends to occur.
[0005]
For this reason, in recent years, for example, as a cyan color material, two types of color materials of dark cyan having a high density and light cyan having a low density are provided, and light cyan is mainly used when outputting an image with a light hue. A type of output device that reduces roughness is becoming popular.
[0006]
The color material amount distribution device that instructs the color material amount to the output device having the same hue color material of the high density and the low density, for each color material of the same hue for a certain image data. It is necessary to obtain and indicate the amount of color material. In addition, if the total amount of color material is excessive, in the case of an electrophotographic printer, there is a risk of cracking when the color material dries, or film peeling that causes the color material to peel off. In the case of a printer, there is a risk that ink that cannot adhere to the paper may flow, and therefore, it is necessary to obtain the color material amount of each color material within a predetermined total amount limit.
[0007]
As a technique for obtaining the color material amount of each color material, conventionally, the gradation values represented by the image data are classified into a plurality of gradation value ranges, and in each gradation value range, for example, only a low density color material is used, and a high density is used. A technique has been proposed in which only a specific color material is used, or a specific amount of a high density color material and a low density color material are used (see, for example, Patent Document 1).
[0008]
[Patent Document 1]
Japanese Patent Laid-Open No. 11-115222 (pages 13-14, FIGS. 7-8)
[0009]
[Problems to be solved by the invention]
By the way, when obtaining the color material amount of each color material in accordance with the gradation value represented by the image data, it is desirable to obtain the desired relationship between the gradation value and the color density. However, in the technique disclosed in Patent Document 1, a desired relationship cannot be reproduced unless the boundary of the gradation value range is appropriately set. To set the boundary appropriately, an image output test and the boundary There is a problem that it takes time and effort to repeatedly correct the position.
[0010]
In view of the above circumstances, the present invention provides a color material amount distribution device capable of easily obtaining a color material amount that reproduces a desired relationship between a gradation value and a color density, and such a color material amount. It is an object of the present invention to provide a color material amount distribution definition creating method for creating a defined color material amount distribution definition.
[0011]
[Means for Solving the Problems]
The color material amount distribution device of the present invention that achieves the above object expresses an image of the color material amount of each of the plurality of color materials when the image is expressed using a plurality of color materials having the same hue and different densities. In the color material amount distribution device obtained based on the gradation value,
A storage unit storing a color material amount distribution definition in which a correspondence relationship between a color material amount and a gradation value of each of a plurality of color materials is defined in a table format;
A color material amount distribution unit for obtaining a color material amount of each of the plurality of color materials from a total color material amount and a gradation value of the plurality of color materials according to the correspondence defined by the color material amount distribution definition stored in the storage unit; It is provided with.
[0012]
According to the color material amount distribution apparatus of the present invention, the correspondence between the color material amount and the gradation value is defined by the color material amount distribution definition in the table format with a high degree of freedom of definition. For this reason, a desired color material amount can be obtained easily and at high speed by using a color material amount distribution definition created in advance so as to reproduce a desired relationship between the gradation value and the color density.
[0013]
Here, in the color material amount distribution device of the present invention, the storage unit includes a plurality of patches in which combinations of the color material amounts of the plurality of color materials are different depending on an output device that outputs an image using the plurality of color materials. A chart output process for outputting the generated chart, a density-color material quantity relationship acquisition process for obtaining a correspondence between a combination of color material quantities and density by measuring a patch of the chart output in the chart output process, and a plurality of colors The correspondence between the color material amount and the gradation value of each material is based on the desired correspondence between the gradation value and the density, and the correspondence between the density and the color material amount obtained in the relationship acquisition process. Color material amount obtained through a color material amount-gradation value relationship deriving process for deriving the total color material amount within each upper limit value for each of the plurality of upper limit values for the total color material amount of the plurality of color materials It is preferable to store the distribution definition. That.
[0014]
As described above, the color material amount distribution definition obtained through the chart output process, the density-color material quantity relationship acquisition process, and the color material quantity-tone value relationship derivation process is the desired value between the tone value and the color density. Therefore, it is possible to reproduce such a desired relationship.
[0015]
Therefore, the color material amount distribution definition creating method of the present invention that achieves the above object is as follows.
Color material amount distribution definition that defines the correspondence between the color material amount of each of the multiple color materials when the image is expressed using multiple color materials having the same hue and different densities, and the gradation value representing the image In the color material amount distribution definition creation method to create
A chart output process for outputting a chart in which a plurality of patches having different combinations of color material amounts of the plurality of color materials are arranged by an output device that outputs an image using the plurality of color materials,
A density-color material amount relationship acquisition process for measuring the patch of the chart output in the chart output process and obtaining a correspondence relationship between the combination of the color material amount and the density,
The correspondence between the color material amount and the gradation value of each of the plurality of color materials is changed to a desired correspondence relationship between the gradation value and the density and a correspondence relationship between the density and the color material amount obtained in the relationship acquisition process. And a color material amount-gradation value relationship deriving process for deriving the total color material amount within each upper limit value for each of a plurality of types of upper limit values with respect to the total color material amount of the plurality of color materials. And
[0016]
According to the color material amount distribution definition creating method of the present invention, based on the accurate correspondence between the combination of color material amounts and the density obtained by measuring a chart output using a plurality of color materials, The color material amount distribution definition is created so as to satisfy the desired correspondence between the tone value and the density and the total amount limit of the color material amount. By using this color material amount distribution definition, the gradation value and the density The desired correspondence with can be easily reproduced.
[0017]
Here, in the color material amount distribution definition creating method of the present invention, the color material amount-gradation value relationship deriving process is such that, for the gradation values in a predetermined range in highlight, the one having the lower density among the plurality of color materials. It is preferable that the process of deriving the correspondence between the color material amount and the gradation value so that only the color material is used.
[0018]
This is because it is easy and effective to output only the color material having a lower density in order to avoid roughness when outputting a highlight image with a lighter shade.
[0019]
Further, in this desirable color material amount distribution definition creation method, the color material amount-gradation value relationship deriving process is such that, in deriving the correspondence between the color material amount and the gradation value, Preferably, this is a process of deriving a correspondence relationship in which the color material amount change is continuous before and after the boundary of the predetermined range.
[0020]
When the color material amount changes discontinuously around the start of entering the color material with the higher density, for example, when gradation is output, the difference in image quality due to the presence or absence of the color material with the higher density is conspicuous, Although it causes image quality degradation, it is possible to avoid such image quality degradation by deriving a correspondence relationship in which the color material amount change continuously changes.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described.
[0022]
FIG. 1 is an external view showing a printing system to which an embodiment of a color material amount distribution apparatus of the present invention is applied.
[0023]
In this external view, a printing system constituted by a computer system 100 and a large inkjet printer 200 is shown. The computer system 100 is connected to an external computer system (not shown) via a communication network 300.
[0024]
The printing system shown in FIG. 1 is a system that can be used as a so-called proof system that confirms the finished image of a printed image in advance. A high-resolution printer. The large-sized inkjet printer 200 corresponds to an example of an output device according to the present invention, and uses ink as an example of a color material according to the present invention. Cyan), M (magenta), Y (yellow), and K (black) images are output in four colors. For cyan and magenta, the density is relatively high with dark ink having a relatively high density. With low light ink. That is, the large-sized inkjet printer 200 is a printer that outputs an image with six colors of ink of Lc (light cyan), Dc (dark cyan), Lm (light magenta), Dm (dark magenta), Y, and K.
[0025]
The computer system 100 of the printing system includes image data representing an image captured by a scanner or the like via the communication network 300 or a storage medium such as a CD-R or MO, and an image representing a page of a printed matter. Data etc. are input. These image data represent images with gradation values of the four colors of CMYK.
[0026]
The computer system 100 functions as the color material amount distribution apparatus of the present embodiment, and image data expressed in CMYK four colors is converted into image data expressed in six colors for a printer by the computer system 100. The converted image data for the printer is output to the large-sized inkjet printer 200. The large inkjet printer 200 receives the image data for the printer, and prints out an image with six colors of ink based on the received image data.
[0027]
A feature of the computer system 100 shown in FIG. 1 as an embodiment of the present invention resides in processing contents executed inside the computer system 100 when functioning as a color material amount distribution device. explain.
[0028]
As a hardware configuration, the computer system 100 includes a CPU 101, a main storage device, a hard disk, a communication board, and the like, and displays a screen and a character string on the display screen 102a according to an instruction from the main body 101. By designating a CRT display 102 to be performed, a keyboard 103 for inputting user instructions and character information to the computer system 100, an arbitrary position on the display screen 102a, an icon displayed at that position at the time of the designation, etc. A mouse 104 is provided for inputting instructions according to the above. In addition, a CD drive for accessing the CD-ROM 105 or the like is also installed in the main body 101.
[0029]
When the CD-ROM 105 storing the program is inserted into the main body 101 of the computer system 100, the program is installed in the computer system 100. When the installed program is executed, the computer system 100 will be described below. A functional structure is constructed.
[0030]
FIG. 2 is a functional block diagram showing a functional structure constructed in the computer system 100.
[0031]
In the computer system 100, there are roughly divided image editing software 110 and printer driver software 120. The image editing software 110 is for editing an image in accordance with a user operation, and the printer driver software 120 is for controlling a large inkjet printer (color printer) 200 to output an image.
[0032]
The printer driver software 120 includes a color matching processing unit 121, a total amount restriction processing unit 122, an ink usage amount setting processing unit 123, a calibration processing unit 124, and a halftone processing unit 125, of which an ink usage amount setting process is performed. The unit 123 functions as an embodiment of the color material amount distribution device of the present invention.
[0033]
The color matching processing unit 121 processes the image data so that the color of the image output by the large inkjet printer 200 matches the color of the document captured by the scanner or the color of the printed matter output by the printing machine. It is.
[0034]
The total amount restriction processing unit 122 obtains the ink usage amount of each of the four colors of CMYK within a predetermined total amount restriction in order to maintain the color tone and impression of the image as much as possible while avoiding the ink flow described above. The specific content of the total amount limitation is irrelevant to the subject matter of the present invention, and thus a detailed description thereof will be omitted. For example, by using a technique for removing the undercolor disclosed in Japanese Patent Laid-Open No. 5-124234, the total amount is limited. Appropriate ink usage can be determined within the limits.
[0035]
The ink usage amount setting processing unit 123 sets the ink usage amounts of the dark ink and the light ink for cyan and magenta with respect to the ink usage amounts of the four colors CMYK obtained by the total amount restriction processing unit 122. is there. Details of the usage amount setting will be described later.
[0036]
The calibration processing unit 124 performs processing for correcting changes over time of the large-sized inkjet printer 200 on the image data, and the halftone processing unit 125 performs according to the ink usage expressed by the gradation value. A halftone image using the ink usage is created.
[0037]
When the image data that has undergone these processes is input to the large inkjet printer 200, the large inkjet printer 200 outputs a print image 210 using six colors of ink. When a printing system composed of the computer system 100 and the large-sized inkjet printer 200 is used as a proof system, the output print image 210 is an image printed by a printing press not only for colors but also for a halftone dot pattern. Reproduced image.
[0038]
FIG. 3 is a diagram illustrating details of the ink usage amount setting processing unit 123.
[0039]
FIG. 3 shows the total amount restriction processing unit 122 and the ink usage amount setting processing unit 123 shown in FIG. 2 as well. Here, for convenience of explanation, dark ink and light ink are only used for cyan and magenta. It is assumed that the usage amount is set.
[0040]
The total amount restriction processing unit 122 receives the ink usage amount of each CMYK without the total amount limitation as a gradation value, and the total amount restriction processing unit 122 supplies the total ink amount C + M + Y + K together with the ink usage amount within the total amount limitation of each CMYK. Is also output.
[0041]
Here, the ink use amount setting processing unit 123 receives the cyan ink use amount C and the total ink amount C + M + Y + K. In the ink use amount setting processing unit 123, a LUT (Look Up Table) 130 corresponding to an example of the color material amount distribution definition referred to in the present invention is prepared in advance, and the LUT 130 includes cyan ink. The ink usage amounts Lc and Dc for light cyan and dark cyan with respect to the usage amount C are recorded in a table format. Further, the LUT 130 includes a table for each of a plurality of types of upper limit values for the cyan total ink amount. The upper limit value for the total amount of cyan ink is obtained based on the total amount C + M + Y + K and the cyan ink usage amount C. For example, the difference between the total amount C + M + Y + K and the total amount limit value is added to the cyan ink usage amount C. Calculated. In the ink usage amount setting processing unit 123, the ink usage amounts Lc and Dc of light cyan and dark cyan are obtained and output according to the upper limit value and the LUT 130.
[0042]
By using the LUT 130, the ink use amount setting processing unit 123 can define the ink use amounts Lc and Dc of light cyan and dark cyan with respect to the cyan ink use amount C with a high degree of freedom. The amount of ink can be determined at a higher speed than the definition using.
[0043]
Since such a LUT 130 has a high degree of freedom of definition, in order to create the LUT 130 capable of obtaining appropriate ink usage Lc and Dc for light cyan and dark cyan, here, the color material amount distribution definition of the present invention is used. One embodiment of the creation method is used.
[0044]
Hereinafter, an embodiment of a color material amount distribution definition creating method of the present invention will be described in detail.
[0045]
FIG. 4 is a flowchart showing an embodiment of the color material amount distribution definition creating method of the present invention.
[0046]
This color material amount distribution definition creation method includes a chart output process (step S01), a density-color material quantity relationship acquisition process (step S02), and a color material quantity-tone value relationship derivation process (step S03). First, the outline of these processes will be described.
[0047]
The chart output process is a process of outputting a color chart in which a plurality of color patches having different combinations of ink amounts of dark ink and light ink are arranged using the large-sized inkjet printer 200 shown in FIGS. 1 and 2. This corresponds to an example of a chart output process in the color material amount distribution definition creating method of the present invention.
[0048]
The density-color material amount relationship acquisition process is a process of acquiring the correspondence between the combination of the ink amounts and the density by measuring the density of the color patches constituting the color chart output in the chart output process. This corresponds to an example of a density-color material amount relationship acquisition process in the color material amount distribution definition creating method of the invention.
[0049]
The color material amount-gradation value relationship derivation process is based on the correspondence relationship acquired in the density-color material amount relationship acquisition process between the combination of the ink amount and the density, and the desired correspondence relationship between the gradation value and the density. This is a process for obtaining the correspondence between the ink amount combination and the gradation value, and corresponds to an example of a color material amount-gradation value relationship deriving process in the color material amount distribution definition creating method of the present invention.
[0050]
Details of each process of the color material amount distribution definition creation method will be described below.
[0051]
FIG. 5 is a diagram showing a color chart output in the chart output process.
[0052]
In this color chart 140, cyan color patches 141 output by a combination of dark cyan and light cyan are arranged, and the amount of light cyan ink used in the color patch 141 is from right to left in this figure. The amount of dark cyan ink used in the color patch 141 increases with increasing distance, and increases with increasing distance from the top to the bottom of this figure. In the chart output process (step S01 in FIG. 4), such a color chart is output.
[0053]
Next, in the density-color material amount relationship acquisition process (step S02 in FIG. 4), the density of each color patch 141 of the color chart 140 output in this way is measured.
[0054]
FIG. 6 is a graph showing the measurement result of the color patch.
[0055]
FIG. 6 shows a graph 151 representing the measurement result of the color patch in the density-color material amount relationship acquisition process (step S02 in FIG. 4) and a graph 152 representing the desired density with respect to the cyan gradation value C. The vertical axis of this figure represents the concentration.
[0056]
The horizontal axis of the graph 151 representing the measurement result represents the light cyan ink amount Lc, and in this graph 151, six graph curves from dark cyan ink amount Dc from “0” to “255” are shown. Has been. Here, gradation values from “0” to “255” are used as gradation values representing the ink amount, and when converted to halftone values, the value “255” corresponds to 100%.
[0057]
On the other hand, the horizontal axis of the graph 152 representing the desired density with respect to the cyan gradation value C indicates the cyan gradation value C. In the color material amount-gradation value relationship deriving process (step S03 in FIG. 4), Using these graphs 151 and 152, ink amounts Lc and Dc of light cyan and dark cyan for an arbitrary gradation value C are obtained as described below.
[0058]
First, a graph 152 representing a desired density with respect to the cyan gradation value C is used to obtain a density with respect to an arbitrary gradation value C. Next, a combination of ink amounts (Lc, Dc) that realizes the density is required. Since there are many combinations (Lc, Dc) of ink amounts that realize a certain density, a combination of ink amounts (Lc, Dc). ) Is uniquely determined, it is necessary to provide a limiting function for limiting the relationship between the light cyan ink amount Lc and the dark cyan ink amount Dc. For example, in the case of the limiting function represented by the straight line 161 along the density axis, the light cyan ink amount Lc is always “0”. In addition, if the limiting function represented by the last rising curve 162 along the graph curve with dark cyan ink amount Dc of “0”, only light cyan is used in the low density (highlight) region, and light cyan ink amount Lc. Reaches the maximum value (ie, “255”), dark cyan is added. Furthermore, in the case of the limiting function represented by the intermediate curve 163, both light cyan and dark cyan are always used from the low density range to the high density range, and the ink amounts of both increase as the density increases.
[0059]
As described above, various limiting functions are conceivable. However, considering the avoidance of roughness in the low density region, it is desirable that the limiting function is such that only light cyan is used in the low density region.
[0060]
In determining the limiting function, it is also necessary to consider the upper limit of the total ink amount of light cyan and dark cyan. When the upper limit value of the total ink amount is, for example, “255”, the region below the dotted line 170 is the allowable range of the ink amount combination (Lc, Dc). Considering that the density reproduction range should be as large as possible within this allowable range, the limiting function represented by the curve 164 is desirable as the limiting function. According to this limit function, only light cyan is used in the low density range, dark cyan begins to gradually enter before light cyan reaches the maximum ink amount, then light cyan is replaced by dark cyan, and the upper limit of the total ink amount A sufficiently high concentration range is reached within the value.
[0061]
When the limit function is determined for each upper limit value of the total ink amount in this way, a combination of ink amounts (Lc, Dc) is obtained according to the limit function, and the combination of ink amounts with respect to the cyan gradation value C (Lc). , Dc) is created, and the LUT 130 shown in FIG. 3 is obtained.
[0062]
In the color material amount-tone value relationship deriving process (step S03 in FIG. 4), the LUT 130 is created in this way.
[0063]
FIG. 7 is a diagram illustrating a data structure of the LUT 130.
[0064]
The LUT 130 includes a series of values 131 representing the cyan gradation value C. In addition to the series of values 131, a series of values 133, each representing the ink amounts Lc and Dc of light cyan and dark cyan, respectively. 134 is associated. A table composed of a series of values 133 and 134 representing the ink amounts Lc and Dc of light cyan and dark cyan is associated with a numerical value 132 representing the upper limit value Imax of the total ink amount of light cyan and dark cyan. It is prepared.
[0065]
By referring to such an LUT 130, it is possible to easily obtain appropriate ink amounts Lc and Dc that fall within the upper limit value Imax of the total ink amount that realizes a desired density according to the cyan gradation value C. .
[0066]
FIG. 8 is a graph showing the ink amounts Lc and Dc of light cyan and dark cyan defined by the LUT 130, respectively.
[0067]
The horizontal axis of this graph represents the cyan gradation value C, and the vertical axis represents the ink amounts Lc and Dc for light cyan and dark cyan, respectively.
[0068]
A curve 181 representing the light cyan ink amount Lc with respect to the cyan gradation value C shows a mountain shape, and the vicinity of the peak of the mountain shape is rounded. On the other hand, a curve 182 representing the dark cyan ink amount Dc shows a monotonous increase, and the dark cyan ink amount Dc is “0” within the predetermined range 183 in the highlight area. Further, before and after the boundary of the range 183, the change in the light cyan ink amount Lc with respect to the change in the cyan gradation value C, that is, the slope of the curve 182 continuously increases from 0. Image quality deterioration due to the start of using dark cyan in the vicinity is avoided.
[0069]
As described above, according to the color material amount distribution definition creating method of the present embodiment, it is possible to easily create an LUT defining appropriate ink amounts Lc and Dc for light cyan and dark cyan, respectively. The color material amount distribution apparatus according to this embodiment that obtains the ink amounts Lc and Dc for light cyan and dark cyan using the LUT can obtain the appropriate ink amounts Lc and Dc easily and at high speed. As a result, appropriate ink amounts Lc and Dc are used from the large-scale inkjet printer 200 connected to the computer system 100 functioning as the color material amount distribution device of the present embodiment shown in FIGS. 1 and 2. A print image 210 with high image quality is output.
[0070]
In the above description, for convenience of explanation, the ink amounts of light cyan and dark cyan and how to obtain the LUT that defines the ink amounts have been described. However, the ink amounts of light magenta and dark magenta, and the inks thereof. It can obtain | require similarly about LUT which defined quantity.
[0071]
In the above description, as an example of an output device according to the present invention, an image is output with six colors of ink of Lc (light cyan), Dc (dark cyan), Lm (light magenta), Dm (dark magenta), Y, and K. However, the output device according to the present invention may be provided with dark ink and light ink for only one of cyan and magenta, or may be cyan, magenta, and black. These three colors may be provided with dark ink and light ink.
[0072]
Further, in the above description, an ink jet printer is shown as an example of the output device according to the present invention. However, the output device according to the present invention represents an image using a plurality of color materials having the same hue and different densities. Any printer may be used as long as it is not limited to an inkjet printer, and a thermal transfer printer, an electrophotographic printer, or the like may be used.
[0073]
【The invention's effect】
As described above, according to the color material amount distribution apparatus of the present invention, the color material amount that reproduces the desired relationship between the gradation value and the color density can be easily obtained. Further, according to the color material amount distribution definition creating method of the present invention, it is possible to create a color material amount distribution definition that defines such a color material amount.
[Brief description of the drawings]
FIG. 1 is an external view showing a printing system to which an embodiment of a color material amount distribution apparatus of the present invention is applied.
FIG. 2 is a functional block diagram showing a functional structure constructed in a computer system.
FIG. 3 is a diagram illustrating details of an ink usage amount setting processing unit.
FIG. 4 is a flowchart showing an embodiment of a color material amount distribution definition creation method of the present invention.
FIG. 5 is a diagram showing a color chart output in the chart output process.
FIG. 6 is a graph showing measurement results of color patches.
FIG. 7 is a diagram illustrating a data structure of an LUT.
FIG. 8 is a graph showing ink amounts Lc and Dc of light cyan and dark cyan defined by the LUT.
[Explanation of symbols]
100 computer system
101 Main body
102 CRT display
102a Display screen
103 keyboard
104 mouse
105 CD-ROM
110 Image editing software
120 Printer driver software
121 Color matching processing unit
122 Total amount restriction processing part
123 Ink usage setting processing unit
124 Calibration processing unit
125 Network processing unit
130 LUT (Look Up Table)
140 color chart
200 Large inkjet printer
210 Print image
300 communication network

Claims (5)

In the color material amount distribution device for obtaining the color material amount of each of the plurality of color materials when expressing the image using a plurality of color materials having the same hue and different densities, based on the gradation value representing the image,
A storage unit storing a color material amount distribution definition that defines a correspondence relationship between a color material amount and a gradation value of each of the plurality of color materials in a table format;
A color material for obtaining the color material amount of each of the plurality of color materials from the total color material amount and the gradation value of the plurality of color materials according to the correspondence defined by the color material amount distribution definition stored in the storage unit. A color material amount distribution device comprising an amount distribution unit. A chart output process in which the storage unit outputs a chart in which a plurality of patches having different combinations of color material amounts of the plurality of color materials are arranged by an output device that outputs an image using the plurality of color materials, and the chart A density-color material amount relationship obtaining process for obtaining a correspondence relationship between a combination of color material amounts and density by measuring a patch of the chart output in the output process, and a color material amount and a gradation value of each of the plurality of color materials, For the total color material amount of the plurality of color materials based on the desired correspondence relationship between the gradation value and the density and the correspondence relationship between the density and the color material amount obtained in the relationship acquisition process. The color material amount distribution definition obtained through the color material amount-gradation value relationship deriving process for deriving the total color material amount within each upper limit value for each of the plurality of upper limit values is stored. The color material according to claim 1, wherein The dispensing device. Color material amount distribution definition that defines the correspondence between the color material amount of each of the plurality of color materials and the gradation value representing the image when an image is represented using a plurality of color materials having the same hue and different densities In the color material amount distribution definition creation method to create
A chart output process for outputting a chart in which a plurality of patches having different combinations of color material amounts of the plurality of color materials are arranged by an output device that outputs an image using the plurality of color materials;
A density-color material amount relationship acquisition process of measuring a patch of the chart output in the chart output process to obtain a correspondence relationship between a combination of color material amounts and a density;
The correspondence between the color material amount and the gradation value of each of the plurality of color materials, the desired correspondence between the gradation value and the density, and the correspondence between the density and the color material amount obtained in the relationship acquisition process And a color material amount-gradation value relationship deriving process for deriving the total color material amount within each upper limit value for each of a plurality of types of upper limit values with respect to the total color material amount of the plurality of color materials. Color material amount distribution definition creation method characterized by In the color material amount-gradation value derivation process, the color material amount and the gradation are set such that only the color material having the lower density of the plurality of color materials is used for the gradation value in a predetermined range in the highlight. 3. The color material amount distribution definition creating method according to claim 2, wherein the color material amount distribution definition creating method is a process of deriving a correspondence relationship with values. In the color material amount-gradation value derivation process, in deriving the correspondence between the color material amount and the gradation value, the color material amount change of each color material with respect to the gradation value change is continuous before and after the boundary of the predetermined range. 4. The color material amount distribution definition creating method according to claim 3, wherein the corresponding relationship is derived.

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