JPS59206838A - Device for determining dot area per cent - Google Patents

Abstract

PURPOSE:To determine easily a dot area per cent by comparing a conversion table for color- density-dot area per cent and a combination of the respective color densities of an object to be measured, displaying the interpolated dot area per cent if both do not coincide and displaying the combination most approximate to the conversion table when both do not coincide. CONSTITUTION:A conversion table for color density-dot area per cent corresponding to the combination of the color densities and the combination of the color densities of plural colors of color separating plates is preliminarily stored in a storage means 10, and the data on the combination of the color densities determined by a means 20 for measuring the color density of an object to be measured is once stored in a storage means 30. A means 40 for selecting the color density compares the combination of color densities in the conversion table for color density-dot area per cent and the combination of color densities of the object to be measured and selects the combination most approximate to the combination of the color densities of the object to be measured among the former. The combination of the dot area per cent corresponding to the combination of the color densities selected in the above-mentioned way is subjected to interpolation by a vector method by a means 60 for interpolating the dot area per cent and is displayed by a means 70 for displaying the dot area per cent. The dot area per cent of the ink of each color is easily determined in the above-mentioned way in the case of expressing the color of the object to be measured.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention provides C (cyan), 1M (magenta), and
The present invention relates to a device for determining the halftone dot area ratio of Y (yellow) and Bk (black) plates.

Conventionally, a large number of color samples for specifying colors may be attached to printing layout sheets. For example, if you want to uniformly fill the background with a certain color, a small piece of paper with the background color is attached as a color sample.

If you want to print the specified part with the same color as this color sample C
, M, Y, and Bk with what dot area ratio.1. To decide which color to use, visually compare this color sample with a printed color chart with the small area ratio changed at approximately 10% intervals, select the most similar one, and select the one that is most similar. The selected color is generally determined based on the fact that the percentage of the halftone dot area of each plate is written on a color chart. However, this method has the disadvantage that it takes time to make the comparison, and that each person selects a different color from the color chart, so that the determined halftone area ratio tends to vary. Accurately specifying the dot area ratio requires an experienced veteran, but even then it is not perfect.

On the other hand, reflection densitometers that can measure the density of an object to be measured and calculate the dot area ratio are currently on the market. In this densitometer, the measured density value is processed by a microcomputer built into the densitometer to calculate the dot area ratio. To calculate the dot area ratio from this density value, the Niel-Nielsen equation is usually used. In order to use this Niel-Nielsen equation, first measure the reference density, set the halftone area ratio of that part to the reference value (100%), and then measure the actual halftone area. It is necessary to measure the analyte for which the ratio is to be determined, and to utilize the relationship with the above-mentioned group concentration.

Therefore, it is only applicable to colors that have a standard density, and is usually used only for monochrome colors. Furthermore, the Niel-Nielsen equation does not require the following equations (the halftone dots are ideally reproduced, and the coefficients that change depending on each element such as the number of screen lines, the density, and the transparency of the paper are set appropriately). Therefore, in actual use, it is not possible to accurately obtain the dot area ratio over a wide range from the light part to the shadow part even if it is a single color.In addition, it is impossible to calculate the dot area ratio for secondary colors or higher. It's totally difficult.

Therefore, such a densitometer cannot display a combination of dot area ratios for each of the Y, M, C, and Bk versions to express the color of the color sample.

In addition, such a conventionally known densitometer can also calculate the halftone area ratio Yl to express the color of the color sample by the following method.
It is not possible to display the M, C, and Bk versions in combination. In other words, Y, M, and C printing inks are not ideal (y ink contains M component and C511i:, and 1M ink contains Y component and C511i:).
In addition, C ink contains M component and Y component. Y used in reality,
1 because the printing ink for M and C is not ideal.
The color of the object to be measured, such as a color sample, is determined by the complementary color relationship of Y, M, and C (
B (blue violet), G (green), R
The dot area ratio can also be calculated using the Niel-Nielsen formula from the density values measured through each (red) filter.

This value does not indicate the dot area ratio of each positive chip of Y, M, and C that is actually required. This will be more clearly understood by the following example. For example, it is easy to understand if we assume that an image with a dot area ratio of 100% is printed using only C ink from a certain ink manufacturer. R filter each of these prints.

If the density is determined through the G filter and the B filter, it will be 1.53.0.52.0.17, respectively, but these values are converted to C1M, which is a complementary color of R, G, and B, respectively.
It is clear that it cannot be used to determine the internal area ratio of the Y-plate mesh. This problem does not apply only to one color of ink (it also applies when multiple color inks are to be overprinted).
f-1:j becomes complicated.

The present invention eliminates the various drawbacks as described above, and allows any color to be printed using inks of YoM, C, or Y.
, M, C, and Bk, the apparatus is capable of easily determining how to combine the halftone area ratios of the respective color plates.

That is, the invention of this application provides a color density-dot area ratio conversion table that shows the correspondence between the combination of color densities and the combination of the dot area ratios corresponding to the combinations of color densities of a multi-valve color separation plate. A first storage means stored therein, a color density measurement means for determining the combination of color densities of the object to be measured, and a second storage means for storing the combinations of color densities determined by the color density measurement means. , the silk combination of color densities of the color density once-halftone dot area ratio conversion table stored in the first storage means, and the color density Kf of the oiled one constant stored in the second storage means.
tf) From among the combinations of color densities in the color density-halftone surface Aoki conversion table by comparing with the silk combination f'I'
Displaying a combination of dot area ratios corresponding to the silk combination of the color density selected by the color density selection means (the color density net 76 consisting of a filter screen and an RB surface area ratio display means) The present invention attempts to provide a device that can obtain historically detailed combinations of dot area ratios using a bond ratio conversion table.

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

FIG. 1 is a conceptual diagram of the apparatus of this application, in which a first storage means f+01 is preliminarily stored with a mesh imaginary surface corresponding to a combination of color densities and a combination of color densities of M6 separation plates of a plurality of colors. A color density-dot area ratio conversion table indicating the correspondence with the combination of fN bundles is stored, and a color density 1111 constant means for obtaining silk combination data of the color density of the target 4111 constant object! 20) The silk matching data of the color density obtained from K is stored in the second storage means (
30) should be memorized once. The color density combination data is stored in the second storage means (30).

For example, if the color density of the object to be measured is set to 1 (a combination of three types of color density obtained through each of the filters, G filter, and B filter), or For example, four types of color densities, including the color densities obtained through an amber filter or an ND filter, are combined with a set of silk and 17.Next, the color density selection means (4O) 1 storage means (
10) and the combination of color densities of the mid-density-dot area ratio conversion table stored in 10) and 'P! of the object to be measured stored in the second storage means (30)! By comparing the densities with the silk combinations, the one closest to the color 7 combination of the object to be measured is selected from among the color density combinations in the color density-dot area ratio conversion table.

In this way, the net corresponding to the silk combination with the color density selected from the color density-clamping force area ratio conversion table 7- as the one closest to the silk combination with the color density of the object to be measured, Iil,
The combination of i area ratios is subjected to appropriate interpolation using a vector method by the dot area ratio interpolation means (60), and then displayed by the imaginary halftone area ratio display means (70). As described above, when printing and expressing the colors of If1lll fixed objects (for example, color samples) with printing ink, each color ink is used as
It is easy to determine whether to overprint with such a dot area ratio.

Figure 2 (al, (+)) shows an example of a color density-dot area ratio conversion table, and on the left is an R filter,
Combinations of color densities obtained through each of the G filter, B filter, and amber filter are shown, and the combinations of halftone area ratios corresponding to the color density combinations shown on the left are shown on the right. ing.

Such a color density-dot area ratio conversion table is as follows (
1-2 be created. First of all, Y, M, C for printing.

Using each ink of Bk, the joint area ratio o% ~ 100
A color chart is created by changing the % size at appropriate intervals, for example, at 10% intervals as in the case of FIG. 2. -f that is.

In the example in Figure 2, numbers 1 to 11 are M, Y, B.
The k version has a clamping force area ratio of 0%, and only the 0 version is changed from 0% to 100% in 10% increments, and numbers 12 to 2
Up to 2, the Y and Bk versions have a dot area ratio of 0%, the M version has a dead area ratio of 10%, and only the 0 version is changed between 10% and 100% in 10% increments. , c, B
Color charts were created using various combinations in which the halftone area ratio of each plate of K was changed at 10% intervals. Such a combination is 114=146 when the halftone area ratio is changed at 10% intervals for each of the Y, M, C, and Bk versions.
This produces 41 different silk combinations.

An R filter and a G filter are applied to each color of the color chart created as described above.

The color density obtained through each filter of the B filter is matched, and the color density obtained through the amber filter and ND filter is added to this to obtain the silk match. As described above, a color density-dot area ratio conversion table is created that shows the correspondence between combinations of color densities and corresponding combinations of halftone area ratios of plates of each color for various colors.

Although it is common to measure color density using the above-mentioned R, (), B amber, or ND filters, it is also possible to use interference filters that have a peak in the absorption part of the spectral reflection curve of printing ink. It's okay.

The same filter used to create the color density-to-small area conversion table must be used when measuring the color density of the object to be measured.

Looking at the color density-dot area ratio conversion table obtained as above, for example, for numbers 1 to 11 in Figure 2, the dot area ratio of each version of M, Y, and Bk is 0%. Even though only the 0 version changes without any change, the color density not only changes through the R filter, which is the complementary color of C, but also the color density through the other G, B, and Amber filters. It's changing. This is because the C ink contains not only the C component but also other color components.

This relationship holds true for other inks as well, and they contain other components. Therefore, when determining the dot area ratio of an object to be measured, it is necessary to take into consideration not only the color density through one filter but also the color density through other filters. The data of the color density-dot area unconverted table is stored in the first storage means (10) (as such storage means, an appropriate storage means such as a magnetic disk, a floppy disk, a ROM, etc. can be used). .

As described above, a color density-dot area ratio conversion table is stored in advance in the first storage means (10).

Further, a color density measuring means (201 is a means for measuring the color density of the object to be measured, and FIG. 6 is a block diagram showing one embodiment of the method. In the example of FIG. 3, one color sample etc. The object to be measured (1) is irradiated by the light source f2+)vc,
The reflected light is input to a photoelectric conversion element (23) via a filter (22), where it is converted into an electric signal (vc).

The filter (221 is the same as the one used when creating the color density-skin area tree conversion table,
6 types of R filter, G filter, B filter, or 4 types of filters including an amber filter or ND filter can be converted fJ'? Vc is attached.

In this case, the filter may be switched electrically or manually. Also, in the example shown in Figure 3, the light from the light source is emitted from an angle of 45 degrees and is received directly above; It's okay. The electric signal 11 generated by the photoelectric conversion element (23) is amplified by the amplifier (24) and sent to the correction circuit ('2
The necessary correction is made in the logarithmic converter (26), the analog signal is converted into a digital signal in the A/D converter (27), and the color density is stored in the second storage means (31'l). ) and stored.

Note that the value of the electrical signal that has been logarithmically converted by the logarithmic converter (26) can be checked on a display meter (28). Note that a digital display may be provided by inserting a display meter (A/r) converter (after 2η).

As described above, the object to be measured is measured for each filter to obtain a combination of color densities of the object to be measured, and these are stored in the second storage means (30) as described above. As the second storage means (30), an appropriate one such as a RAM can be selected.

The color density selection means (40) is the second storage means (30) K
The stored color density match of the object to be measured is compared with the color density match in the color density-dot area height conversion table stored in the first storage means (10), and the color density-dot pattern is calculated. Combining the color densities of the object to be measured from the combinations of color densities in the area east conversion table -+! The selection is done in the following way. DRl chromaticity
Do, DB, DA.

In addition, the color density through the R filter, G filter, B filter, and amber filter at the nth number of the color density-dot area ratio conversion table is TR(n), TO(nl, TB(n), respectively. ), TA(nl
shall be. Next, the combination of color densities of the object to be measured DR, Do,
D.B.

DA and color density - nth color density of skin area soil conversion table
The combination TR(ril, To(n,
l.

The button combination T, (nl, T(, (nl
, TF, inl, TA(n!).

In front of V! 3A(n)'t[5A(n)12= [:TR(nl -DR]2+
[To(n)-D. ]2-4-[Tl-3(r))--
−Dl,]2+[TA(ding))---DA]2 If the distance 5Afnl is the minimum, the value of n is [8Afn112
is the minimum and matches the value of n. Therefore, using the above relational expression, we will search for combinations of m densities in the color density-reticular area ratio conversion table that minimize [5Atn)12 by sequentially changing the value of n from TA-1 to the end. Good 5
The mouth value at which Afnl is the minimum can be found. 5Afn) is the minimum, and the color density button combination in the fi'I density-dot area ratio conversion table corresponding to n is determined as the one closest to the color density combination of the object to be measured.I-7, that color Silk combination of density (corresponding to -'f') Silk combination of halftone area ratio of each plate of Y, M, C, Bk is determined.

In this case as well, if (SAin112 becomes zero during the search, that is, the color density of the object to be measured matches the color density in the color density - halftone area ratio conversion table) If something is found, it corresponds to the color density silk combination at the value of n at that time.
Since the combination of dot area ratios f is the desired data, the subsequent search may be discontinued.

The combination of halftone dot area N ratios of each of the Y, M, C, and Bk versions determined as described above is subjected to appropriate interpolation using a vector method by the halftone dot area ratio interpolation means (60), and then is converted into a halftone dot area ratio. Displayed by display means (70). As the dot area ratio display means, an appropriate device such as a printer or a CRT display can be used.

The combination of the halftone dot area ratios displayed as described above indicates the halftone dot area ratio of each plate, and if each color ink is printed using the combination of the halftone dot area ratios obtained in this way, it will be possible to measure the It is possible to obtain printed matter that is the same as or similar to the actual product. For example, if the 125th color density is selected as the closest color density to the combination of color densities obtained by fixing the 4111 fixed object to 4111, then from the table in Figure 2, the 0 version is 6
0% for the M version, 10% for the Y version, and 0% for the Bk version.
60)! Therefore, after being subjected to appropriate interpolation using the vector method, it is displayed by the halftone area ratio display means. Therefore, by printing with the silk combinations shown here using each type of ink, it is possible to obtain printed matter that has the same color as the object to be measured or a color similar to it.

By the way, when actually printing the paper used for the color chart used to create the data for the two-color density-mesh area ratio conversion table (the type of paper used may be different).

mCreate data for density-dot area ratio conversion table'''f
When printing is actually performed at a printing factory, the solid density value that is based on the printing factory may differ from the solid density value that is used as the standard at that printing factory. In such a case, create a density-dot area ratio conversion table55j, because the conditions for creating the color density-dot area ratio conversion table and the conditions for actual printing are different. When comparing the color density button combinations of the table and the color density combinations of the object to be measured, the above-mentioned differences in conditions must be taken into consideration.

Below, we will explain an example of how to take into account the differences in these conditions, but since it would be extremely complicated to completely compensate for the differences in the five conditions, in the following example, "'f" shows the case of approximate correction.

Figure 4 is a graph for explaining the relationship between color density and halftone area ratio.For simplicity, the explanation will be based on the assumption that these 11 lines have a linear relationship, but the same concept can be applied to curves. It is sufficient to perform correction.

In Figure 4, when creating the five-color density-to-imaginary area ratio conversion table, the portion where only the 0th edition is 100% and all other editions are 0% is obtained through the R filter, which is a complementary color of C. The concentration is X. , and all the plates are %f, that is, the color density obtained through the R filter on the part of the color chart paper where no ink is applied is N. Suppose it was. In addition, solid printing is performed in advance on the paper to be actually printed using a 0 plate with a density determined as the base solid density at the printing factory and a plate with a dot area ratio of 100%. The color density of the 0 plate subjected to iK to be actually printed was measured using the apparatus of the present invention through an R filter, and the color density was X. ', and the fh density obtained by measuring unprinted paper using the apparatus of the present invention through an R filter is N. ′. In FIG. 4, the straight line (al) and the straight line (b) respectively show the relationship between the color density and the 11-point area ratio when creating the P density - small area ratio conversion table and when actually printing. If the color density obtained by passing the object to be measured, such as a sample, through the R filter using the apparatus of the present invention is . The area ratio P' should be obtained, but a value different from the halftone area ratio P that should actually be obtained15
゜Therefore, in order to correct the error in this case, the color density value of the object to be measured is corrected as follows. In other words, the color density value obtained by measuring the object to be measured through the R filter is When the color density after correcting the value of l is corrected, the color density of the object to be measured obtained through the R filter is corrected according to the relational expression.Similarly, only the M version is 100%. ,Y
For books printed with 100% plate only and 100% Bk plate only, the color density is determined for each book through G filter, B filter, and amber filter. Obtain the color density through the amber filter, and use these color density data to correct the color density of the object to be measured through the G filter, B filter, and amber filter (or ND filter). Combining the color densities after each correction. , Dl, Dl, Dlt& are used for comparison with the color density combinations in the color density-small area ratio conversion table. That is, when performing the correction in this example, first of all, the f! The three densities are obtained using the apparatus of the present invention through R, G, and B filters, and the reference solid printing area of each color ink at the printing factory is determined using the apparatus of the present invention. The color density is determined by measuring the M ink through a G filter, the Y ink through a B filter, and the Bk ink through an amber filter. These data are stored in the device of the present invention. Next ``$1llllll
R, (), B using the apparatus of the present invention.

The color density measured through each of the amber filters is corrected using the previously determined color density of the paper and the color density value of the reference solid print area.

In the correction example described above, the correction data was obtained by actually measuring the actual printing (the color density of the paper used and the color density of the solid printing area of each color ink) using the apparatus of the present invention. If the data has been obtained in advance, it may be possible to input the data using a numeric keypad or the like.

In addition, as a method of correcting vc1, as a color density measuring means, the light part and the shadow part are R, G, and B.

If a densitometer that can be adjusted independently for each amber filter is used, the following procedure may be used.

In other words, the light section measures the unprinted portion of the paper to be printed, and each of C, M, Y, and Bk in the one-color density-to-skin area ratio conversion table is 0% (
KR, G so that the color density becomes (in the case of number 1 in Figure 2)
, B, and anonymous filters, and the shadow area is determined by the paper C, M, Y,
Prepare a print with a standard solid density for each Bk color ink, measure the solid density part of the C ink through an R filter, and calculate the color density of the shadow part at this time as the color consistency. - Adjust the color density of the R filter when C in the halftone area ratio conversion table is 100% (number 11 in Figure 2), and similarly for KM ink, Y ink, and Bk ink. Each of Y, M, and Bk in the color density-small area ratio conversion table is 100 when measured through the G filter%B filter and the amber filter.
%, adjust the color density of the G filter, B filter, and anonymous filter so that they are the same. After making the adjustments in this way, the actual object to be measured is measured to determine the combination of imaginary area ratios.

Various correction methods have been explained above, but all of them are 10
It is not possible to correct 0%.

The precision of the halftone dot area ratio determined as described above depends on the accuracy with which the halftone dot area ratio is created in the color density-small halftone area ratio conversion table. In the example shown in FIG. 2, the coverage area ratio is changed at 10% intervals, so the accuracy is up to 10%.

Therefore, if a song requires a highly accurate fine area ratio, it is sufficient to create a width density-dot area ratio conversion table with the required accuracy.

5. Then, the amount of data in the color density-dot area ratio conversion table becomes extremely large, and creating such data is extremely time-consuming and requires a large storage device. As well.

One drawback is that it takes a long time to perform any comparison calculations on the measurement data of the fixed object on the plate.

The invention of this application (mainly to eliminate such drawbacks).

It is an object of the present invention to provide a device capable of determining the dot area ratio at intervals finer than the data interval of the halftone dot area ratio in a color density-to-visual area ratio conversion table.

That is, the invention of this application provides a combination of color densities and a plurality of ρ
a first storage means storing a color density-fine area ratio conversion table showing a correspondence relationship with a combination of mesh A=area ratio corresponding to the silk combination of the color saturation of the intermediary solution version of No. 4; a color density measuring means for determining the combination of color densities of the object to be measured; a second memory means for storing the silk combinations of the color densities determined by the color density measuring means; and a memory in the first memory means. The color density - dot area ratio conversion table is compared with the color and density match of the object stored in the second storage means to determine the color density - dot area ratio. ρ density selection means for selecting the one closest to the combination of color densities of the object to be measured from among the silk combinations of color densities in the area ratio conversion table; and the silk combinations of the selected color densities and the object to be measured. If the combination of color densities does not match, a combination of halftone dot area ratios interpolated by a vector method based on the color density-to-skin area ratio conversion table is determined;
If the combination of the selected color densities and the combination of the color densities of the object to be measured do not match, the interpolated dot area ratio is displayed, and if they match, the selected color densities are displayed. and small area ratio display means for displaying combinations of halftone area ratios corresponding to the combinations of.

The interpolation means will be explained in more detail below.

First, a first storage means (10) in which a color density-halftone and white area ratio conversion table is stored, and a color density measuring means f201.
.

The second storage means (j30) selects the combination of color densities closest to the silk combination of the color densities of the object to be measured from the color density-mesh and inner area ratio conversion tables by the color density selection means (40).
-Ro.

The color density selected in this way is the silk combination or the distance SA
``''''['In the case of f, if it is selected as a result that completely matches the color density of the object to be measured, then the corresponding combination of halftone area ratios is used as is. It may be displayed using the area ratio display means (70).However, the silk combination of the selected color density or the 5A
If it is selected in a case other than =0, the halftone dot area ratio corresponding to the selected color density set 24- is calculated by the halftone dot area ratio interpolation means (60
) to obtain a combination of dot area ratios that can print a color that is even closer to the color of the target object.

First, from the color density-dot area ratio conversion table with dot area ratios in 10% intervals as shown in Figure 2, select the one closest to the color density combination d (DR, Do, DB, D2,) of the object to be measured. is selected, and the combination of color densities is t(TR.

To, TB, TA), and the silk combination with the corresponding halftone area ratio is P (c, m, y, bk).

In the following explanation, C and M will be excluded from Bk as a combination of dot area ratios to simplify the explanation.

Although the explanation will be limited to the three colors Y (7'), the interpolation process can be performed in exactly the same way even when Rk is not excluded.

FIG. 5 is an explanatory diagram of the stripe interpolation method, and R, (), B
The color densities obtained through the R, G, and B filters are the combination of color densities t (TR, T,, TB).

TA) is shown as the origin.

Here, if we set the vector) -3 (B,, Bo, island), then we get Aki=DR-TR1Bo-Do-To, BB=D
B-TT].

Further, for each thread alignment P (c, m-, y) of the mesh surface M ratio corresponding to the color density combination t, 1 unit (-
Silk combination P5 (c ± 10. m + 10. y ± 10) with a halftone dot area ratio shifted by f (that is, 10% in the case of Fig. 2)
is set, and the corresponding color density combination t3 (TR3
, To3. T, ) can be known from the color density-dot area ratio conversion table. The dot area ratio P3 (C±1
01m±10. y±10), whether to take a positive or negative value is determined depending on whether each component of the stripe vector Btd (BRlBo, BB) is greater than or equal to zero or less than zero, and if it is greater than or equal to zero, it is considered positive.

If it is smaller than zero, it is considered a negative value. In this case BR,
C±10. depending on the number of each of Bo and BB. m+
10. The number to be adopted for each of y±10 is determined.

Now, considering the vector B0,3, the vector B0,3 can be expressed as a combination of several vectors.

For the sake of simplicity, the following explanation assumes that each component of the vector Btd is greater than zero, but the same procedure can be performed even in other cases.

If the C component is 10% thicker than the combination of the dot area ratios P (Ch mb 'Y), and if the C component and m
If each component is 10% thicker, the combinations of halftone area ratios are P, (c + 10, m, y
).

Let it be P2 (c+10.m+10.7).

Combination of dot area ratios P4. The combination of color densities corresponding to P2 is determined by tl (TR1'T01' TBi ) and t2 (
TR2'To2, TB2).

Therefore, the vector is, 3 is the vector y, , , −;,
, 2. -g,,,,.

It can be expressed as t1+s1t2+s2j,3-i'tjj.

Therefore, the vector ■ is the vector "tt1'"tj t
2 ” fj, 2i, 5 by αBt, 1+βBjij, 2+γBj, 2i, 3 =
It is expressed as B cut.

Here, the vector Btd (BRlBG, BB) is as described above (since each degree component is known, α and β are obtained from the above relational expression).

Find r.

Therefore, the combination of color densities of the object to be measured d (DRb D(3
The combination of halftone area ratios P(c, m.

A combination of dot area ratios P'(c', r
n'.

y') is c' since the table in Figure 2 is at 10% intervals.
= c+αX10 m'; m+β×10 de=y+γ×10.

As described above, the combination of halftone area ratios after interpolation y(C',
Go, y) are determined.

Note that there are various methods of expressing the vectors B0 and B3 as a combination of other vectors in addition to those described above, so any vector may be used.

However, in order to obtain a reasonable interpolated value, as shown in Figure 5, the combinations of color densities obtained from the color density-dot area ratio conversion table must be connected so that the vector reaches color density combination t3. Preferably, a vector is selected.

When the combination of color densities in the one-color density-dot area ratio conversion table and the combination of color densities of the object to be measured completely match, the dot area ratio display means (70) displays the middle density of the matched color density. The combination of dot area ratios corresponding to the combination is displayed, and if they do not match completely, the combination of the dot area ratios interpolated as described above is displayed.

FIG. 6 is a flowchart showing how the dot area ratio is determined using the apparatus according to the invention of this application described above.

Since the invention of this application has the above structure, it has the following effects.

First, in FIG. 1, according to the apparatus of the invention of this application.

Even if the colors to be reproduced in printing are specified as actual colors, such as in a color sample, it is very easy for an experienced person (and in a short period of time The halftone dot area ratio of the halftone positive chip can be determined.

Next, according to the apparatus of the invention of this application, the reduction area ratio of the silk positive for each plate is always determined in a standardized form, unlike the conventional method in which humans judge it, so the quality of printed matter can be controlled. becomes easier.

Furthermore, according to the present invention, it is extremely easy to obtain a combination of dot area ratios with even higher accuracy than the queen effect.

Furthermore, according to the invention of this application, the processing time required for interpolation to find the combination of highly accurate halftone area ratios is extremely shortened.

(bl 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. 4 is a graph illustrating the relationship between color density and halftone area ratio.
FIG. 51 is a diagram for explaining a method of interpolation processing of halftone dot area ratios, and FIG. 6 is a flowchart for determining a combination of halftone dot area ratios using the apparatus of the present invention.

(1)...Object 1111 constant (10)...First storage means (20)...Color density measuring means (21)...
・Light source (221... Filter (23)... Photoelectric conversion element (24)... Amplifier f25)... Correction circuit (26)... Logarithmic converter (2η... jV
D converter (28i...display meter (30
)...Second storage means (40)...Color density selection means (70)...Dot area ratio display means (60)...
・Dot area ratio display means Patent applicant Toppan Printing Co., Ltd. Figure 4 Figure 5

Claims (1)

[Claims] (Before the 11 color density combinations and the multiple color separation plates, the color density-dot area ratio conversion table that shows the correspondence relationship between the combination of color density combinations and the combination of halftone area ratios corresponding to the combinations of color density is stored. a color density measuring means for determining the combination of color densities of the object to be measured; a second storing means for storing the combinations of color densities determined by the color density measuring means; The combination of color densities in the color density-dot area ratio conversion table stored in the first storage means is compared with the combination of color densities of the object to be measured stored in the second storage means, and the color color density selection means for selecting a combination of color densities closest to the color density combination of the object to be measured from among the combinations of color densities in the density-dot area ratio conversion table; and the combination of the selected color densities and the object to be measured. If the combination of color densities does not match, calculate the combination of dot area ratios interpolated by the vector method based on the color density-dot area ratio conversion table. If the selected color density combination and the color density combination of the object to be measured do not match, the interpolated halftone area ratio is displayed, and if they match, the screen corresponds to the selected color density combination. 1. A dot area ratio determining device comprising: a dot area ratio interpolation means for displaying a combination of dot area ratios.