JPS60142221A - Deciding method of color reproducibility - Google Patents

Abstract

PURPOSE:To decide easily whether a reproduction by a prescribed ink of a color to be reproduced is suitable or not, and its degree, by comparing a color information - dot area rate converting table derived in advance, with color information detected from an object to be measured. CONSTITUTION:A color information - dot area rate converting table is stored in a storage means 10. A color information data of an object to be measured, derived by a color measuring means 20 is stored in a storage means 30, compared with color information of the color information - net point area rate converting table of the storage means 10, color information of the table, which is the most similar to the measured color information is selected, a correcting quantity is calculated by a correcting means 50 from a combination of its dot area rate, and a combination of the corrected net point area rate is derived. Also, in accordance with whether its combination exists within the range described in the table or not, whether a reproduction of a color of the object to be measured, by a prescribed ink is suitable or not is decided, and its result is outputted from an output means 60.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for determining whether the color of a treasure covered by a predetermined ink f can be reproduced.

Conventionally, printing layout sheets are often accompanied by numerous () color samples for color specification. For example, when a background is to be uniformly filled with a certain color, a small piece of paper showing the color of the background is attached as a color sample.

If you want to print the specified part with the same color as this color sample,
Use this color sample to determine the dot area ratio for each plate (C (cyan), M (magenta), Y (yellow), including Bk (black) if necessary). and 1
The halftone area ratio of each plate is printed by changing the halftone area ratio at approximately 0% intervals, and the most similar color is selected by visually comparing it with the color chart. Generally, the percentage is determined by using the information written on the color chart. However, this method C has the disadvantage that it takes a long time to make the comparison, and the colors selected from the color chart vary depending on the person, and the determined halftone dot area ratio tends to vary.

In addition, there are colors in the color sample that are not color chart 1/medium υ. For example, it is well known that bright secondary colors such as green, orange, and purple cannot be reproduced with ordinary process inks. The main reason for this is that the chromaticity of the process ink is considerably distorted from the theoretical chromaticity of the three primary colors due to reasons such as economic efficiency, printability, light fastness, and water-based properties. be. We also compared these colors with the color chart, and...
If you compare it with the color you think is the closest, you can visually determine that it is a color that cannot be reproduced, but it is not possible to quantitatively determine to what extent the color cannot be reproduced.

Therefore, in retouching, we decided that if we slightly changed the color that seemed to be the closest, we would get closer to the color sample, so we printed by changing the halftone dots in various ways.'-1i o Printing Looking at the results, the color reproduction is thicker (
There are many cases where the net has to be repositioned. During this time, material costs and time losses are significant.

The present invention relates to a method for eliminating the above-mentioned drawbacks and determining the reproducibility of the color of an object to be measured, such as a color sample, using a predetermined ink.

Next, the present invention will be explained in detail with reference to the drawings.
reactor.

FIG. 1 is a conceptual diagram of the apparatus according to the invention of this application, in which the first storage means (river) stores color information in advance and the color information of a color separation plate of a plurality of colors, and corresponds to the dot area ratio. A color information-dot area ratio conversion table showing the correspondence relationship with the combination of is stored, and the color measuring means +2F stores the color information data of the object to be measured.
The color information data determined by 11 is stored in the second storage means (3
01VC is temporarily stored. The color information data stored in the second storage means (30) includes, for example, the color density of the object to be measured, which is obtained by passing the color density of the object to be measured through each of the R filter, G filter, and B filter. Ikomonoya + fiK is a combination of the color densities of 44tf to which the color densities obtained through the external pressure of each filter, such as an amber filter or ND filter, are added. or chromaticity.

Next, the color information selection means (40) selects the first storage means (
The color information of the color information-halftone area ratio conversion table stored in 10) is compared with the color information of the object to be measured stored in the second storage means (3O+) to calculate the color information-halftone area ratio. q and the color information in the area ratio conversion table that is closest to the color information of the object to be measured.

The combination of halftone area ratios selected in this way is corrected by the correction means (5
At 01K, a correction amount is calculated based on the color information-dot area ratio conversion table, and a combination of corrected dot area ratios is found. Determining suitability for reproducing the color of the object to be measured using a predetermined ink, depending on whether or not the combination of halftone dot area ratios determined in this way exists within a range defined by the color information-dot area ratio conversion table; Output means t6 for the result
0).

Figure 2 [al, (bl) shows an example of a color information-dot area ratio conversion table as a color information-dot area ratio conversion table when color density is adopted as color information; shows the combinations of color densities obtained through each of the R filter, G filter, B filter, and amber filter, and the right side shows the combinations of halftone area ratios corresponding to the color density combinations shown on the left side. It is shown.

Such a color density-dot area ratio conversion table is as follows (
It's the first time I've made it. First, print paper [Y, IJC, Bk
Using the ink of the valley of
Create a color chart that varies by % and does not actually print by 1°j. 1-However, in the example of FIG. 2, numbers 1 to 11 are r, h 0. y, EJ K version has a halftone dot area ratio D%, and C version only has a range of 1 between 0% and ioo%.
The dot area ratio of the M version is 1D%, and the dot area ratio of the M version is 1D%, and the dot area ratio of the C version is 40%. 10 between ~100%
They are changed in % increments, as follows: Y", 1./l, C, Bk
Color charts 1 were created using various combinations in which the dot area ratio of each plate was changed at 10% intervals. Such a combination is 114=1464 when changing the dot area ratio at 10% intervals for each version of Y, M, C, Bl<
This produces one combination.

Apply an R filter and a G filter to each color of the color chart created as described above.

obtained through each filter of B filter;);t+,
Choose a combination of color densities, or a combination that adds the so-called 1y color obtained through an amber filter or ND filter. By doing the above up < and summarizing various colors, a color density-dot area ratio conversion table is created that shows the correspondence between the combination of color densities and the corresponding combination of halftone dot 1nj grading ratio of each color plate. be done.

In addition, it is common to measure color density using each of the R6(), B, amber, or ND filters mentioned above. It may be of. Creating a color density-dot area coverage ratio variable carbon table 1- The same filter as that used at the time of π must be used when measuring the color density of the object to be measured.

For example, in Fig. 2, m number 1 to number 11, the mesh of each version of M, Y, and Bk is obtained. Even though the point area ratio is 0 and does not change, and only the C version changes, it is a complementary color of C, and the color only passes through the R filter (and other G
, B, and amber filters, the color density also changes.

this! -! This is because the C ink contains not only the C component but also other color components.

Such a relationship is the same for other inks, which include one other component. Therefore, when determining the halftone dot coverage of a fixed object, it is necessary to take into account not only the color density through one filter but also the color density through other filters. The data of the color density-dot area ratio conversion table is stored in the first storage means (10), and such storage means include a magnetic disk,
Use an appropriate device such as a phronopysque or ROM.

+11.1 < As above, the first storage means oo) stores in advance a color information-dot area ratio conversion table 7).

Further, the color measuring means (20) measures the color of the object to be measured to obtain color information, and FIG. 5 is a block diagram showing one embodiment thereof. The example in FIG. 6 shows an example in which color density is used as color information, and an object to be measured (1) such as a color sample is irradiated by a light source (2I),
The reflected light is input to the photoelectric conversion element +23+ via the filter (22+) and converted into an electrical signal there.The filter (22) is the same as the one used by π when creating the color density-dot area ratio conversion table. It is equipped with three types of filters: R filter, () filter, and B filter, or four types of filters including an amber filter or NI) filter, etc., are attached to the conversion 0T function. The conversion of the filter in this case is 1
It doesn't matter if you can switch it manually, or you can switch it manually. In addition, in the example shown in Fig. 5, the light from the light source is emitted from an angle of 45 degrees and is received directly above.
The light may be received in the direction of .

The signal generated by the photoelectric conversion element (23) is sent to the amplifier (
It is amplified by the correction circuit (25) and subjected to logarithmic conversion processing by the logarithmic converter (2fil).
The analog signal is converted into a digital signal by the /D converter (27), and the color information is inputted to the second storage means (3til) and stored in At. The processed electrical signal can be checked on a display meter (28).

The display meter (28) is A/1 converter (2
It may be used as a digital display by pressing the button after 7).

As described above, the color information of the measured object is obtained by measuring the measured object for each filter.
The information is stored in the storage means (30). As the second storage means (30), an appropriate one such as RAM can be selected.

The color information selection means (40) selects the combination of the color information of the object to be measured stored in the second storage means (30) and the first storage means (
10) Compare the color information stored in the color information-dot area ratio conversion table with the color information in the color information-dot area ratio conversion table, and select the color information closest to the color information of the object to be measured from among the color information in the color information-dot area ratio conversion table. However, the selection should be made as follows. For example, if color density is used as color information, each of the R filter, G filter, B filter, and anonymous filter of the object to be measured should be selected. The color densities obtained through the above are DII, D, D, DA, and the nth number of the color 1 degree - dot area ratio conversion table as a color information - dot area ratio conversion table is The color densities through the R filter, G filter, B filter, and anonymous filter are respectively '1゛1, (I)) and 'f'.
Let o(n,)-TB(11),'+:'A(n). Next, the colors of the object to be measured are combined DIL, DG, ■]
8.1 Combination 14 R(n) of the nth number of color density in the color density-dot area ratio change table)
“l”, o(n).

TB(+11. Combination of color densities T R(n), T Q that minimizes the distance 5A(rl) between TA(n)
(n), T o (n), and TA (n).

Distance 5A (nj is C5A(n):) 2-CTn(n)-Dn) 2+
C”'Ll (n) ])a ]2-1('rn(n
It can be determined from the relational expression l-Dt+]2+c'rA(nl-r++,]2.

Distance 5A (the value of n that minimizes nl is C5A(n))
Match the value of n for which 2 is the minimum. Therefore, using the above relational expression, we can calculate the combination of colors (aIf) in the color density-dot area ratio conversion table that minimizes [5A(n)]2 by n-
By sequentially changing the value of n from 1 to the end and searching, the value of n that minimizes 3A(n) can be found. 5A(n
The combination of color densities in the color density-dot area ratio conversion table corresponding to nvc with the minimum l is determined as the closest combination of color densities of the object to be measured, and Y corresponding to that combination of color densities, Determine the combination of dot area ratios for M, C, and BK versions.

In this case as well, if (SA(n))2 becomes zero (in the middle of the test), then the combination of the color density of the object to be measured and the color density - halftone area ratio If a matching color density is found in the conversion table, the data is used to find the combination of halftone area ratios corresponding to the combination of colors at the value of n at that time, so subsequent searches will be performed. You can cancel it.

If the color information of the closest combination of halftone dot area ratios selected in this manner completely matches the color information of the object to be measured, the selected halftone dot area ratios are correct values, but in many cases they do not match.

Moreover, in such a search method, even if a color cannot be reproduced with a predetermined ink, the color in the table is selected as the closest color. Even if halftone printing is performed at a halftone dot area ratio corresponding to this corner-folded color, the color is quite different from the color of the object to be measured, which is a problem. Does the present invention overcome these drawbacks? il
l It is not related to the method of determining the color appearance of treasures.

An explanatory diagram is shown in FIG. The rotary axis shows the dot area ratio of C, M, and Y, and 0. a, l), c, d, e,
The lattice point at f,9 is C,+1.,The area ratio of Y is o
(0,0,0), a(0,0,+oo), b(o,10
0,100), c(0,1oo, 0)-d(100,
D, 0), e(100, 0, 100), f'(100,
100, 1oo), g(11]0, ioo, 0). This solid? The image is divided into 10% units, and color densities through R, G, and B filters as shown in FIG. 2 correspond to each grid point.

If the object to be measured has been printed with the above-mentioned pheasant ink in the predetermined printing order ff1ll, then the combination of densities of the object to be measured in 1-h is the three-dimensional o a b shown in FIG. ,2
(] e It is included in the solid defined by fg. However, some objects actually used to be measured are not included in this solid. This is because the actual color samples used are various. A14 printed under various conditions using ink of various hues.
It's for the sake of it.

It is obvious that if the color density of the object measured through each filter is higher than the maximum value in the solid, or lower than the minimum density value, it will go outside the solid. . For example, if you print with a predetermined ink that is thicker than the standard, the printing density will be higher than the standard even at 100%, and it will go outside the three-dimensional image.

However, since each color density value of the 11 objects measured through each filter exists between the minimum density value and maximum density value of the color-dot area ratio conversion table, it is difficult to imagine that it exists in this solid. No limit. The reason for this may be the difference in hue between the predetermined ink and the ink of the object to be measured. For example, if a normal process ink is used as the prescribed ink, 1-
Ru. Process ink ('', yellow ink is close to ideal, but magenta ink contains /an, yellow components, and cyan ink contains magenta, yellow components.

The object to be measured is a specially adjusted bright orange color that cannot be reproduced with the specified ink (including cyan ink).
It is a color, and the valley color density value measured through each filter J(, 0, B) exists between the minimum density value and maximum density value of the color 4F-halftone area ratio conversion table. Things 1
In an attempt to reproduce the color of this object to be measured, only two inks, yellow and magenta, were overprinted and printed ().

Assume that the density values measured through the B filter are equal. The density value passed through the G and B filters is the main component of the density value of this printed matter. Even though cyan ink is not used, the colors printed in this manner appear muddy due to eye fogging compared to the color of the object to be measured (color sample). That is, the density of the cyan component passed through the R filter is much higher in the printed material than in the object to be measured. This is due to the influence of the cyan component contained in the magenta ink of the predetermined ink.

In this case, even if the cyan component is shown as a value between the maximum and minimum values of the color 1 degree - halftone area ratio conversion table, including the density through the 1-R filter, the actual color is This indicates that the

In this way, just because each color density value exists between the minimum density value and the maximum density value, the three-dimensional plane (0, a-e,
d green color, plane oc, 9d purple color, plane o a b
In the case of the orange color C, a certain color is selected only from within the three-dimensional object during a search, but some colors of the actual object exist outside the three-dimensional object.

In this way, in order to determine whether the color of the object to be measured is actually a color that exists outside the three-dimensional object, the present invention uses color information obtained by measuring the object to be measured. , correct the halftone area ratio selected in the search as the closest one. The correction amount is calculated based on the combination of the color information and the halftone area ratio.

The color reproducibility of the object to be measured is determined based on whether or not this corrected combination of halftone dot area ratios exists within the range defined by the color information-dot area ratio conversion table. The method will be explained below using an example.

First, from the color density-to-halftone coverage conversion table with halftone dot area ratios at intervals of 10% as shown in Figure 2, the color density combination d (DR-DC+, D+1, DA) of the object to be measured is the closest one. is selected, and let the combination of color densities be Mo(T o, ]゛., TB, TA), and the corresponding combination of halftone area ratios P(c, rn, y, bk). In this case, for example, it is assumed that the dot area ratio is on the order of 1%.

In the following explanation, in order to simplify the explanation, the explanation will be limited to the six colors C-M and Y excluding 13k as combinations of dot area ratio '1'', but the combinations of dot area ratios will be limited to six colors '1'', excluding -Bk. It can be corrected in exactly the same way.

If the halftone dot area ratio m−y of P is between 10% and 90%, the halftone dot area ratio is set at 1° with P as the center. % It exists in the inside, that is, in the solid (Fig. 4), which is shifted in the direction of magnitude. Therefore, as shown in FIG. 5, [point A+B+C1I)+E, which is separated by ±10% from P.

lj'-G-1() with the required precision Z[-+
Divide the grid, interpolate the color density of each grid point, determine the value, select the point with the minimum distance using the above formula using the combination of interpolated color densities, and calculate the value of this point. By correcting the value of , it is possible to find a combination of halftone area ratios that satisfies the required accuracy.

However, if at least one color among the halftone area ratios of the point P selected by searching is 0% or 100%,
The point that indicates the actual color does not exist within the solid, but exists outside the solid.
There is a possibility that 1- Therefore, it becomes necessary to consider, for example, a solid in which the -10% or 110% point protrudes outside the square.

1m simply (well, the rate of change from 10 to 0 is 110
The rate of change from 90 to 100% is 110%.
All you have to do is agree on the point. For example, (c, m, y) 4s”(
-1o-100,0) once value is (10,100,O
) concentration value (026,139,078) and (Olloo
, 0), the change in density is (-0,09, -004, -0.07). Therefore, the combination of dot area ratio (
-1o.

The density of (008.161.06) is changed by changing the density value of (0,1oo,0) at this rate of change.
4). Similarly [110% point is also 100% from 90th round]
What is necessary is to change the density of the 100th coefficient point at the rate of increase of . In the above example, 10 to 0 or 90 to ioo
Did you get it by changing only %? Several points in the solid, for example 20.10
．． You can also measure the function at 6 points at 0% and the density at the -10% point.

In this way, the expanded human body is divided into the required accuracy, and the distance between the point indicated by each grid point and the measured value is calculated.The above-mentioned person selects the point with the minimum distance. However, the value of this point can be used to calculate the dot area ratio of P.11 The colors that can be reproduced with a given ink exist in a solid that is not expanded by the combination of dot area ratios after correction.
f, that is, the halftone dot area ratio of each color must be between 0 and 100%. If there are no differences such as measurement errors in color information, even 1% is enough to go outside of the three-dimensional image, and it cannot be reproduced with ink7
However, when the value is once adopted as a color 'h4 report, the measurement accuracy is about ±002 in terms of values. On the brighter side, if the density value changes by 0.02, the halftone area ratio changes by about 5%. Therefore, it may be determined that the color can be reproduced even if the combination of the corrected dot area ratios is about 6% outside the three-dimensional space. However, if the difference is smaller than that, it cannot be ignored and the color cannot be reproduced. Be negative (awesome, or 1
The larger the value is than 00%, the further away it is from the three-dimensional image, indicating that it is reproduced as a color.

In this way, depending on whether or not a corrected combination of dot area ratios exists within the range defined by the color information-dot area ratio conversion table, that is, the above-mentioned three-dimensional object, the object to be measured with the predetermined ink is It is possible to determine whether the color reproduction is appropriate or not.

The method described above only considers widths up to 110% at the smallest width and 110% at the largest.

If the value is limited to -10% to 110%, the measured color may not exist in the expanded solid, and may be even more distant.

In such a case i? The method I described cannot completely capture the extent to which I was unable to reproduce the situation. Therefore, by eliminating such defects, we judge whether the color of the object to be measured can be reproduced by the specified ink, and if the color cannot be reproduced by the specified ink, we evaluate the extent of the problem. There is also Hiroju soup.

In such a case, the following procedure may be used.

As mentioned above, even if at least one color of the halftone dot area ratio of point 1] selected by search is 0% or 100%, the halftone area ratio is shifted by 10% in the size direction r with P as the center. Divide the solid into the required precision, calculate the distance between the point indicated by each grid point and the measured value, and select the point where the distance is the minimum using the above formula, and calculate the distance of this point. The value 1 of the combination of dot area ratios (value of P?) is corrected, and the combination of dot area ratios that satisfies the required accuracy is determined.

If one or more of the corrected combinations of dot area ratios is the same. Next, use the corrected point P to determine the extended \L body, and do the sleeve IE hair as before. By repeating this:l-1111'l until the corrected point no longer corresponds to the dot area ratio on the boundary surface of the expanded solid, it is possible to accurately correct the dot area ratio. In this way, the corrected dot area ratio O ratio or how much smaller or larger than 100% is reproducible with the specified ink. It shows the amount of deviation from the original, and it shows the extent to which it cannot be reproduced. In this way, if the image cannot be reproduced using a predetermined ink, the extent to which it cannot be reproduced can be determined. By the way, according to the above 9 ['' method, it is necessary to calculate the distance by 61 times using the above formula for each grid point in the solid, and since this calculation is repeated, it takes a long calculation time.
The following method can also be adopted, and according to this method, the amount of correction can be determined more easily.

FIG. 6 is an explanatory diagram of this correction method, and shows R, G, B q
+++ is the color information obtained through the filters R-0 and B, respectively, and the color information combinations t, (T, , -'rG, q
゛, □) are expressed as 100 points.

Here vector B=jd(Bll-Bo, Bs)
If you set 13R==DR-TR-B,=1). -T
o, B11=D, l-''8.

Furthermore, for each combination P (c, m, y) of halftone area ratio for the color information combination tK, 1 unit ('1
- That is, in the case of Fig. 2, a combination P3 (c±10, ■1±10yyyyyyyyyyyyyyyyyyyyyyyyyyio) is set, which is a combination P3 (c±10, (TI+
5-T05, TR3) can be known from the color information-dot area ratio conversion table. When the dot area ratio is negative or exceeds 100%, color information is determined in the same way as in the case of the three-dimensional image described above.

The dot area ratio P5 (C±10, In±1o-y±10
), whether to take the positive or negative is a vector]
: (I,, 1 Determined depending on whether each component of (Bn, Ba, Bo) is greater than or equal to zero or less than zero,
If it is greater than or equal to zero, it is considered a positive value, and if it is less than zero, it is considered a negative value. In this case, C±10− m±1o−y±10 depending on the number of each of B, , Bo, 1B+1
Noso, 11. In response, the number of items to be adopted is determined.

can be expressed as a composition of several vectors.

For the sake of simplicity, the following description will be made assuming that each component of the vector 13ta is greater than zero, but the same procedure can be performed even in other cases.

Combination P (c, m, y
), the combinations of dot area ratios when the C component increases by 10% and when the C component and m component each increase by 1110% are expressed as p, (c+10.m= y
), P2 (c+io, m+IO,y).

Combinations of color information corresponding to f11 combination Pl, P2 of the above-mentioned dot area ratio t+ ('I'IN -'I'OI,
Ts+ ) and f; 2 ("n 2, l1lo, ,
, "II 2 )" can be set to %I.

Therefore, the vector Bt, j 3 is the vector "'tt1
- Bt1t2, expressed as 1- happens.

Therefore, vector Btd is vector Bttl, Bt1t2
, Bt2t, αBI, t1+βBt11,2
It can be expressed as +γBt2t3 = Btd.

Here, since each component of the vector I31 (1(BRlBo, BB) is known as described above, α, β, and γ are calculated from the above relational expression.

Therefore, the combination of halftone area ratios P (c, m .

A combination of dot area ratios P'(c', tn'
, y') is c
' = c-1αX10 In' ”” m×βX10 de=ygoγX1D.

The combination of halftone area ratios after correction is as follows.
7, m', y') are determined.

Note that there are various methods of expressing vector Btt-5 as a combination of other vectors in addition to those described above, so any vector may be used.

However, in order to obtain an appropriate correction value, the vector obtained by connecting the combinations of color information should be obtained from the color information-dot area ratio conversion table as shown in FIG. A vector choice is preferred.

If this 5 vc vector method is adopted, the processing time required for correction to find the combination of dot area ratios with high accuracy can be extremely shortened. Based on the combination of dot area ratios corrected in this way, color reproducibility can be determined in the same manner as in the above-mentioned method.

The thus requested determination result and the extent to which it cannot be reproduced are outputted by the output means tli[l) VC. Various output means can be selected as appropriate, and for example, a display device such as a CR'I' display or a printer can be selected.

Since the present invention has the above configuration, it has the following effects. First, according to the method of the present invention, if the color sample, etc. 41tj<Reproduction 1-When the desired color is specified as the actual color, the color to be reproduced can be reproduced with the specified ink, but is it not possible? It is extremely easy to judge whether the reproducibility is appropriate or not, even by an experienced person.

Further, according to the present invention, in addition to the above-mentioned effects, it is also possible to quantitatively determine the extent to which the effect cannot be reproduced.

[Brief explanation of the drawing]

FIG. 1 is a conceptual diagram of the device of the present invention, and FIGS. 2(a) and (b).
) is an explanatory diagram of a color density-dot area ratio conversion table, FIG. 6 is an explanatory diagram of one embodiment of the color density measuring means, and FIG. Figures 5 and 6 are diagrams for explaining the method of correcting the dot area ratio, respectively. (1)...Object to be measured (10)...First storage means (
20)...Color density measuring means (211...Light source (22)
・・Filter (23)・Photoelectric conversion element (24)・・
Amplifier (2:il...correction circuit (26)...logarithmic converter (27)...A/l) converter (z8)...
Display meter (30)...Second note 1: Means (4
0)...Color density selection means (50)...Correction means (6
0)...Output means rr', 41 + - 51st gI

Claims (1)

[Claims] 11) A color information-dot area ratio conversion table indicating the correspondence between combinations of dot area ratios of predetermined inks and color information is prepared in advance, and the color of the object to be measured is determined. Measure and obtain the color '1a information, and extract the color information (
Select the combination of dot area ratios that is closest to the above-mentioned color information, and input the correction amount of the combination of dot area ratios that is closest to the obtained color information by 1 - js + I into the color information - dot area ratio conversion table. The combination of halftone dot area ratios obtained by calculating the closest combination of halftone dot area ratios and applying the correction amount to the supplementary IE is defined by the color information-halftone dot area ratio conversion table. 1. A method for determining color reproducibility, characterized in that whether or not the predetermined ink is suitable for reproducing the color of the object treasure is determined based on whether or not the color exists within a range. (2) Halftone dots made with predetermined ink... A color information-halftone dot area ratio conversion table showing the correspondence between the combination of i-achievement rates and color information is prepared in advance, and the color of the object to be measured is measured. obtain the information, select from the conversion table one combination of halftone dot area ratios that is closest to the obtained color information, and select the closest halftone dot area ratio combination based on the obtained color information. The correction unit for the combination of is calculated based on the color information - halftone dot area ratio conversion table, and the combination of the closest halftone dot area ratios is corrected by the correction amount to obtain the corrected halftone dot area ratio. The adequacy of reproducing the color of the object to be measured by the predetermined ink is determined based on whether the combination of 1- exists within the range defined by the color information-dot area ratio conversion table, and based on the correction amount. The corrected combination of dot area ratios is defined by the color information-dot area ratio conversion table.
(In the case of presence '1-stone, determine the extent to which it cannot be reproduced with the predetermined ink based on the degree of separation from the range 1-
A method for determining color reproducibility that takes this as a sign.