JP2001103330A - Color conversion table generating method and device, and proof generator using the device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To convert desired color data processed by a 1st device into color data processed by a 2nd device in a bound state. SOLUTION: A color conversion table generating section 18 sets part of a color conversion table into a bound state according to a bound condition received from a binding condition acquisition section 23 and stores the setting result to a color conversion section 14. The color conversion section 14 converts print image data C, M, Y, K into proof image data C', M', Y', K' on the basis of the color conversion table with this binding condition, which are outputted to a printer 16. The printer 16 outputs a print proof according to the proof image data C', M', Y', K'.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for creating a color conversion table for converting color data processed by a first device into color data processed by a second device, and a proof using the color conversion table. Related to a creating device.

[0002]

2. Description of the Related Art For example, when a color image is prepared as a printed matter, in order to obtain a desired printed matter, it is necessary to consider various printing conditions such as the type of ink used for printing, printing paper, and illumination for observing the printed matter. There is. In order to set these printing conditions, printing may be performed under various printing conditions. However, it is impractical to perform test printing corresponding to all combinations of such a large number of printing conditions. This is because a great deal of time and costs are wasted for test printing.

[0003] Therefore, a printing proof creation apparatus has been developed which can easily simulate the finished state of a printed material without actually performing printing. In this print proof creation apparatus, device-independent colorimetry of a predicted print material color is performed by performing a conversion process in consideration of various printing conditions on print image data provided for creating a print product. After the data is generated, the colorimetric data is converted into proof image data in consideration of the characteristics of the print proof generating device, and then a proof is generated based on the proof image data.

In this case, printing conditions can be freely set by a conversion table for converting print image data into colorimetric data, so that a proof can be created easily and inexpensively, and a desired printed matter can be obtained from the proof. It is possible to determine the printing conditions that can be used.

By the way, all colors of a color print can be formed in principle by three colors of C (cyan), M (magenta) and Y (yellow), and these three colors are constituted. Ink does not always have ideal spectral characteristics. Therefore, in order to compensate for such a problem, K (black) ink is usually further added to form a color print in four colors. Accordingly, in order to create a more accurate proof, the print proof creating apparatus also performs C, M, Y, K
Are used.

Here, just because the printed matter and the proof are colorimetrically coincident may not always be sufficient. As the most prominent example, when the proof is formed by a combination of C, M, and Y which is colorimetrically equivalent to the proof even though the printed matter constituted by the halftone dots is formed only by the K ink, When viewed microscopically, the observer may feel uncomfortable. In addition, although the printed matter is formed only with the Y ink, the proof may include M in addition to Y. further,
If the halftone dot area ratios of the printed matter and the proof are different, even if they are colorimetrically matched, the appearance may be felt differently. This is particularly noticeable in highlights and shadows of the image. There is a similar problem with the difference in dot gain.

[0007]

SUMMARY OF THE INVENTION According to the present invention, a second device is provided in which desired color data processed by a first device is constrained.
It is an object of the present invention to provide a method and apparatus for creating a color conversion table that can be converted into color data processed by a device.

Further, the present invention provides a proof creating apparatus capable of creating a proof without discomfort corresponding to the content of an evaluation when an proof of an image created by a first device is created and evaluated by a second device. The purpose is to provide.

[0009]

In order to solve the above-mentioned problems, the present invention provides color data D processed by a first device.
In a method of creating a color conversion table for converting the color data into color data D ′ processed by the second device,
A color conversion table between at least a part of the color data D and D 'is created based on the constraint condition, and a color conversion table between the remaining color data D and D' is created in colorimetric correspondence. It is characterized by doing.

Further, according to the present invention, the color data D processed by the first device is replaced with the color data D 'processed by the second device.
A constraint condition setting means for setting a constraint condition; and a color conversion table between at least some of the color data D and D 'based on the constraint condition. The color data D, D '
And a color conversion table creating means for creating a color conversion table between them in a colorimetric correspondence.

Further, the present invention converts image data composed of color data D processed by the first device into image data composed of color data D 'processed by the second device using a color conversion table, In a proof creating apparatus for creating a proof of an image created by the first device by the second device, constraint condition setting means for setting a constraint condition, and color conversion between at least some of the color data D and D ' A color conversion table creating means for creating a table based on the constraint conditions, and creating a color conversion table between the remaining color data D and D 'in a colorimetric manner; and a color conversion table creating means. A color conversion unit that converts the color data D into the color data D ′ using the created color conversion table; and converts the proof based on the color data D ′. Characterized in that it comprises a proof output means for force, the.

In this case, for example, when a constraint condition is set so as to restrict the conversion relationship between specific primary color data or secondary color data selected from C, M, Y, and K, the first device is processed. When the image data to be processed consists of only the specific primary color data or secondary color data, the image data processed by the second device is converted so as to consist only of the specific primary color data or secondary color data. You. Therefore, after converting the image data processed by the first device into the image data processed by the second device using the color conversion table set based on such a constraint condition,
By creating a proof using a printer or the like, the image created by the first device and the proof created by the second device can be combined with a selected specific primary color or 2
The comparative evaluation can be performed in a state where the next color has no discomfort.

When the constraint condition is set so as to store the dot area ratio of the specific range of the color data D and D ', the image created by the first device and the image of the second device are set in the specified specific range. The halftone dot area ratio with the proof to be created can be matched, and the comparative evaluation of the images can be performed without any discomfort. Note that the constraint condition for storing the dot area ratio of a specific range can be set for each specific color data D, D '. In addition, by setting a connection range as a constraint between the specific range and the other range, the specific range includes an image created by the first device and a proof created by the second device. Matching the dot area ratios, creating a proof corresponding colorimetrically using the color conversion table in the other ranges, and creating a proof in which the dot area ratios are continuous without discomfort in the connection range. Can be.

Further, when the constraint conditions are set so as to preserve the dot gains of the color data D and D ', the image created by the first device and the proof created by the second device are set to the dot gain. Can be compared and evaluated in a state where they are matched.

[0015]

FIG. 1 is a block diagram showing the overall configuration of a print proof creating apparatus 10 according to the present embodiment.

The print proof creating apparatus 10 is based on image data C, M, Y, and K for printing separated into four colors of C (cyan), M (magenta), Y (yellow), and K (black). This is an apparatus for creating and evaluating a proof of a printed matter created by the printing machine 12 (first device) using the printer 16 (second device, proof output unit). The print proof creating apparatus 10 converts color data D including the print image data C, M, Y, and K into a
It has a color conversion unit 14 (color conversion means) in which a color conversion table for converting color proof image data C ', M', Y ', K' into color data D 'is set.

The print proof creating apparatus 10 has a color conversion table creating section 18 (color conversion table creating means) for creating a color conversion table set in the color converting section 14. The color conversion table creation unit 18 has a print profile storage unit 19 that stores a print profile set according to the printing conditions of the printed matter created by the printing machine 12.
A (first profile storage unit) is connected to a printer profile storage unit 21 (second profile storage unit) that stores a printer profile set according to proof output conditions created by the printer 16. Note that the print profile storage unit 19 and the printer profile storage unit 21 constitute a color conversion table storage unit.

Here, the printing conditions are, for example, conditions such as ink used for printing, printing paper, printing pressure at the time of printing, characteristics peculiar to the printing machine 12, and the like. Are set corresponding to the combination of. The output conditions are, for example, conditions such as ink used for printout, print paper, characteristics unique to the printer 16, and the like, and a plurality of printer profiles are set corresponding to a combination of these output conditions. .

Further, the color conversion table creating unit 18
A constraint condition acquisition unit 23 for acquiring constraint conditions added when creating a color conversion table is connected. The constraint condition acquiring unit 23 acquires a constraint condition set and stored in advance in a constraint condition storage unit 25 (constraint condition storage unit) or a constraint condition set by an operator using the constraint condition setting unit 27, and performs color processing. It is supplied to the conversion table creation unit 18. The constraint condition acquisition unit 23 (constraint condition selection unit) selects a desired constraint condition from the constraint condition storage unit 25 based on information input by the operator using the constraint condition setting unit 27, and creates a color conversion table. It may be supplied to the unit 18.

The constraint condition acquiring unit 23, the constraint condition storage unit 25, and the constraint condition setting unit 27 constitute a constraint condition setting unit. The constraint condition setting means, the color conversion table creation unit 18, the print profile storage unit 19, and the printer profile storage unit 21 constitute a color conversion table creation device according to the present embodiment.

The print proof creating apparatus 10 of the present embodiment
Is basically configured as described above. Next, a method of creating a color conversion table in the print proof creating apparatus 10 will be described.

First, a method for creating a basic color conversion table before the constraint conditions are set will be described with reference to FIGS.

The basic color conversion table is a print profile 22 stored in the print profile storage unit 19.
And a printer profile 24 stored in the printer profile storage unit 21 and a K gradation conversion table 26.

The print profile 22 converts color data D consisting of print image data C, M, Y, and K into CIE colorimetric data L ^* , a ^* , and b ^* , which are device-independent image data ^. Is a conversion table to be converted into. The print profile 22 measures the colorimetric data L ^* , a ^* , b ^* of the printed matter printed under predetermined printing conditions by the printing machine 12 from the print image data C, M, Y, K, for example. It can be obtained as a relationship for converting the print image data C, M, Y, K into the colorimetric data L ^* , a ^* , b ^* .

The printer profile 24 converts the colorimetric data L ^* , a ^* , and b ^* into color data D composed of proof image data C ', M', Y ', and K' corresponding to the output characteristics of the printer 16. ′. The printer profile 24 is set in accordance with the output characteristics of the printer 16, and can be obtained according to the flowchart shown in FIG.

First, the area ratio of the proof image data K 'is set to 0%, and the remaining proof image data C', M ',
A plurality of proof image data C ', M', Y ', K' with Y 'in increments of 10% are generated (step S1), and the proof image data C', M ', Y', K 'are generated. Then, a chart composed of a plurality of patches is output by the printer 16 using the printer (step S2). Next, the colorimetric data L ^* , a ^* , b ^* of each patch is measured using a colorimeter (step S3). Then, the proof image data C ′,
M ′, Y ′, K ′ (0%) are converted to the colorimetric data L ^* , a ^* ,
forward conversion table to convert to b ^* LUT (C'M'Y '
K ′ → Lab) is obtained (step S4).

Next, the forward conversion table LUT (C ')
Using M′Y′K ′ → Lab), the colorimetric data L ^* , a ^* , b ^* for the proof image data K ′ (0%) is converted into proof image data C ′, M ′, Y ′. An inverse conversion table LUT (LabK '→ C'M'Y') is obtained (step S5). In this case, the inverse conversion table LUT
(LabK ′ → C′M′Y ′) can be obtained by using the Newton method which is a typical example of the successive approximation method.

Next, the area ratio of the proof image data K 'is set to 10%, 20%,..., 100% (Step S).
6) Similarly, by repeating the processing of steps S1 to S5, the colorimetric data L ^* , a ^* , and b ^* for the fixed proof image data K 'are converted to the proof image data C', M ', Y'. Conversion table LUT (L
abK ′ → C′M′Y ′) are obtained (step S7).

The plurality of inverse conversion tables LUT (LabK '→ C'M'Y') obtained as described above are stored in the printer profile storage unit 21 as the printer profile 24.

The K gradation conversion table 26 is stored in the printer 16.
The gradation of the print image data K is converted in accordance with the output characteristics of
The proof image data K 'is created, and the colorimetric values of the printed matter created only by the print image data K are equal to the proof colorimetric values created only by the proof image data K'. It is set as follows.

The color conversion table creation section 18 combines the print profile 22, printer profile 24 and K gradation conversion table 26 set as described above,
A color conversion table storing K for converting color data D composed of print image data C, M, Y, and K into color data D 'composed of proof image data C ′, M ′, Y ′, and K ′. create.

Next, the color conversion table creating section 18 changes the color conversion table created as described above according to the constraint conditions, and creates a new color conversion table.

FIG. 4 shows a display screen for setting a constraint condition for preventing color mixing. In this display screen, C, M,
It is possible to set a constraint condition that restricts the conversion relationship between the primary color data of Y and K or the secondary color data of R, G, and B. Therefore, it is assumed that the operator has set, for example, the constraint conditions for restricting the primary color data of Y and the secondary color data of R (= M + Y) and G (= C + Y) using the constraint condition setting unit 27. .

In this case, the print profile 2 shown in FIG.
2. A color conversion table obtained by synthesizing the printer profile 24 and the K gradation conversion table 26
K → C′M′Y′K ′), the color conversion table creator 18 prints an image for printing in response to the constraint condition for restricting the Y primary color data acquired by the constraint condition acquisition unit 23. Image data Y for printing when data C = M = K = 0
Into a color conversion table LUT (00Y0 → C′M′Y ′) for converting image data into proof image data C ′, M ′, Y ′, K ′
K ′) is converted to proof image data C ′ = M ′ =
Assuming that K ′ = 0, the LUT is changed to (00Y0 → 00Y′0) and set in the color conversion unit 14.

Similarly, the color conversion table creating section 18
Is a color conversion table LUT (0MY0 → C′M′Y ′) for the constraint conditions for restricting the R and G secondary color data.
K ') and LUT (C0Y0 → C'M'Y'K')
To the color conversion table LUT (0MY0 → 0M′Y′0)
And LUT (C0Y0 → C′0Y′0), and set the color conversion unit 14.

After setting a new color conversion table in which the constraint conditions are set in the color conversion unit 14 as described above, arbitrary print image data C, M, Y, and K are converted into the color data with the constraint conditions. The image data is converted into proof image data C ′, M ′, Y ′, and K ′ by the conversion table, and supplied to the printer 16. The printer 16 creates a proof based on the proof image data C ', M', Y ', K'.

In this case, when the print image data C, M, Y, and K are composed of Y-only image data, R-only image data, or G-only image data, other colors are mixed. Proofs without spells are created. Therefore, even when the proof is magnified and observed, since the colors match the printed matter, the printing conditions can be evaluated without any discomfort.

A set of a plurality of constraint conditions is set in the constraint condition storage unit 25 in advance, and based on information specified by the operator using the constraint condition setting unit 27, the constraint condition acquisition unit 23 May be selected from the constraint condition storage unit 25 and supplied to the color conversion table creation unit 18 to create a color conversion table.

FIG. 5 is an explanatory diagram in the case where a constraint condition capable of matching the area ratios of images in a specific range is set. As shown in this drawing, the operator inputs the respective primary color data of the printing image data C, M, Y, K and the respective primary color data of the proofing image data C ′, M ′, Y ′, K ′. , An area ratio matching range 28a for matching the dot area ratio,
28b, a color matching range 30 for matching colors without changing the basic color conversion table, and between the area ratio matching ranges 28a and 28b and the color matching range 30;
It is possible to arbitrarily set the connection ranges 32a and 32b that gradually shift from the halftone dot area ratio matching state to the color matching state. Note that the area ratio coincidence range 28a and the connection range 3
2a is a range set on the highlight side of the image,
The area ratio matching range 28b and the connection range 32b are ranges set on the shadow (solid image) side of the image.

In this case, the color conversion table creating unit 18
For the area ratio coincidence ranges 28a and 28b, the color conversion table LUT is set so that the print image data C, M, Y and K are equal to the proof image data C ', M', Y 'and K'. (CMYK → C′M′Y′K ′) is changed. Further, for the connection ranges 32a and 32b, since the print image data C, M, Y, and K are each equal to the proof image data C ′, M ′, Y ′, and K ′,
The color conversion table LUT (CMYK → C) is interpolated so as to gradually shift to the relationship of the color conversion table LUT (CMYK → C′M′Y′K ′) already set corresponding to the color matching range 30. 'M'Y'K').
For the color matching range 30, the color conversion table LUT (C
MYK → C′M′Y′K ′) is kept as it is.
The color conversion table LUT (CM
YK → C′M′Y′K ′) is set in the color conversion unit 14.

A solid line shown in FIG. 6 indicates a color conversion table LUT (CMY) set in the color conversion unit 14 in a case where the print image data C is converted into the proof image data C '.
K → C′M′Y′K ′).

Using the color conversion table set as described above, arbitrary print image data C, M, Y, K are converted into proof image data C ', M', Y ', K'. When the proof is created using the printer 16, since the area ratios of the printed matter and the proof match in the area ratio coincidence ranges 28a and 28b, images having no unnatural feeling in the area ratio are compared and evaluated. be able to. In particular, a proof without discomfort can be obtained in the vicinity of a highlight of an image where the influence of the change in the area ratio is remarkable, so that the proof can be evaluated more effectively.

The color conversion table creating section 18 further includes:
A color conversion table LUT (CMYK →
C′M′Y′K ′) can be changed.

That is, the print image data C, M, Y,
The difference between K (proof image data C ′, M ′, Y ′, K ′) and the luminance L ^* of the printed matter (proof) is influenced by the dot gain based on the characteristics of the printing paper (proof paper) and the ink. , The input / output relationship as shown by the solid line in FIG. In consideration of this relationship, the color conversion table LUT (C
By changing MYK → C′M′Y′K ′), the effect of the dot gain can be reproduced on the proof, and a more accurate image evaluation can be performed.

Specifically, the brightness of the printing paper itself is T0,
When the ink is recorded as a single color of any one of the print image data C, M, Y, and K on the printing paper (solid 100%), the luminance is T1, the halftone dot area ratio is t, and the ink is used. Assuming that the luminance at the time of recording is Tt, the effective halftone dot area ratio Te of the printed matter is Te = (T0−Tt) / (T0−T1) (1) Further, the luminance of the proof sheet itself is P0, and any one of the proof image data C ′, M ′, Y ′, and K ′ corresponding to the print image data C, M, Y, and K for the proof sheet. Let P1 be the luminance when the ink is recorded as solid (100% halftone) and Pp be the luminance when the ink is recorded with the halftone dot area ratio p, and the effective halftone dot area ratio Pe of the proof is Pe = (P0−Pp) / (P0−P1) (2)

In order to make the effective halftone dot area ratio Te of the printed matter coincide with the effective halftone dot area ratio Pe of the proof, it is assumed that the equations (1) and (2) are equal, and p = P ^-1 ｛P0 − (T0−Tt) · (P0−Pp) / (T0−T1)｝ (3) The relation between the halftone dot area ratio p of the proof and the halftone dot area ratio t of the printed matter can be obtained. In equation (3), P ^-1 is an inverse function of Pp.

Therefore, when a constraint condition for storing the dot gain of the specific primary color data is set, the color conversion table LUT (CMYK → C ′) for the specific primary color data is set.
M′Y′K ′) according to equation (3), a new color conversion table LUT (CMYK → C′M ′)
Y′K ′) can be obtained.

FIG. 8 shows a constraint condition setting screen according to another embodiment. On this setting screen, it is possible to set whether or not primary color data and secondary color data are simultaneously restricted. When the constraint conditions for simultaneously constraining the primary color data and the secondary color data are set, C, M, Y, K,
All the R, G, and B color data are constrained before and after the conversion.

In the setting screen of FIG. 8, C,
It is possible to specify in which range the halftone dot area ratio is to be matched with each of the primary color data of M, Y, and K. In addition,
In the embodiment shown in FIG. 8, a constraint condition is set such that the halftone dot area ratios match in the highlight (0%) and shadow (100%) of the primary color data.

In the above-described embodiment, after the color conversion table is created by fixing the relationship between the print image data K and the proof image data K ', a new color conversion table with constraint conditions is created according to the constraint conditions. Since it is created, a restricted relationship is always obtained for K (black).

On the other hand, after a basic color conversion table is created without fixing K (black), the image data for printing C, M, Y, and K including K (black) is generated as shown in FIG. It is also possible to set a constraint condition for preventing color mixing shown in FIG. Similarly, the setting of the constraint condition of the area ratio matching priority and the setting of the dot gain matching constraint shown in FIG. 5 can be performed.

In the above-described embodiment, the color conversion table creating unit 18 creates a basic color conversion table before setting the constraint conditions, and changes the color conversion table according to the constraint conditions. However, the color conversion table may be created in consideration of the constraint conditions from the beginning.

[0053]

As described above, according to the present invention, with the desired color data processed by the first device constrained,
A color conversion table that can be converted into color data to be processed by the second device can be created.

Further, by using the above-mentioned color conversion table, when a proof of an image created by the first device is created and evaluated by the second device, a proof without discomfort corresponding to the content of the evaluation is created. be able to.

For example, the image created by the first device and the proof created by the second device can be compared and evaluated in a selected specific primary color or secondary color in a state where there is no discomfort.

Further, the halftone dot area ratio of the image created by the first device and the proof created by the second device can be matched, and the comparison and evaluation of the images can be performed without any discomfort.

Further, an image created by the first device and a proof created by the second device can be compared and evaluated in a state where the dot gains are matched.

[Brief description of the drawings]

FIG. 1 is a schematic configuration block diagram of a print proof creation device to which a color conversion table creation method and device and a proof creation device of the present invention are applied.

FIG. 2 is a block diagram for explaining a method of creating a basic color conversion table.

FIG. 3 is a flowchart of a method for creating the printer profile shown in FIG.

FIG. 4 is an explanatory diagram of a display screen for setting a constraint condition for preventing color mixing.

FIG. 5 is an explanatory diagram for setting a constraint condition for area ratio matching priority.

FIG. 6 is an explanatory diagram of a color conversion table changed according to a constraint condition for area ratio matching priority.

FIG. 7 is an explanatory diagram of a relationship between image data and luminance by a dot gain.

FIG. 8 is an explanatory diagram of a screen for setting a constraint condition for preventing color mixing and giving priority to area ratio matching.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Print proof preparation apparatus 12 ... Printer 14 ... Color conversion part 16 ... Printer 18 ... Color conversion table preparation part 19 ... Print profile storage part 21 ... Printer profile storage part 23 ... Restriction condition acquisition part 25 ... Restriction condition storage part 27 ... Constraining condition setting sections 28a, 28b ... Area ratio matching range 30 ... Color matching range 32a, 32b ... Connection range

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5B057 CA01 CA08 CA12 CA16 CB01 CB08 CB12 CB16 CC01 CE17 CH01 CH07 5C077 LL12 LL19 MM27 MP08 NN05 NP07 PP33 PP36 PP37 PP38 PP66 PQ12 PQ22 PQ23 SS01 SS02 SS05 TT02 BT08 MA04 MA11 NA03 PA03 PA07

Claims (17)

[Claims] 1. A method for creating a color conversion table for converting color data D processed by a first device into color data D 'processed by a second device, wherein a constraint condition is set and at least a part of the color data is set. Data D,
A color conversion table between the color data D and D ', and a color conversion table between the remaining color data D and D' in colorimetric correspondence. How to make. 2. The method according to claim 1, wherein said constraint condition is a condition for restricting a conversion relationship of at least one primary color data. 3. The method according to claim 1, wherein the constraint condition is a condition for restricting a conversion relationship of at least one secondary color data. 4. The method according to claim 1, wherein the constraint condition is at least a part of the color data D,
A method for creating a color conversion table, characterized in that the condition is a condition for storing a dot area ratio of a specific range in D '. 5. The method according to claim 4, wherein the specific range is set on a highlight side and / or a shadow side of the color data D and D ′. 6. The method according to claim 4, wherein said constraint condition is at least a part of said color data D,
D ′, the condition for matching the halftone dot area ratios of the specific range, and the halftone dot area ratio of the connection range between the specific range and the other ranges are calculated from the halftone dot area ratio of the color data D by the color data And a condition for gradually shifting to a dot area ratio of D '. 7. The method according to claim 6, wherein said condition for gradually shifting is obtained by interpolating a halftone dot area ratio of said specific range and a halftone dot area ratio of said connection range. How to create a color conversion table. 8. The method according to claim 1, wherein the constraint condition is at least a part of the color data D,
A method for creating a color conversion table, characterized by a condition for storing a dot gain of D '. 9. An apparatus for creating a color conversion table for converting color data D processed by a first device into color data D 'processed by a second device, comprising: constraint condition setting means for setting constraint conditions; A color conversion table between some of the color data D and D 'is created based on the constraint conditions, and a color conversion table between the remaining color data D and D' is created in a colorimetric correspondence. A color conversion table creation device, comprising: a color conversion table creation unit. 10. An apparatus according to claim 9, wherein said constraint condition setting means comprises: constraint condition storage means for storing various constraint conditions; and constraint condition selection means for selecting a desired constraint condition from said constraint condition storage means. Means for producing a color conversion table. 11. The apparatus according to claim 9, further comprising: a color conversion table storage means for storing a color conversion table corresponding to a colorimetric relationship between all the color data D and D '; A color conversion table creating apparatus for changing the color conversion table based on the constraint condition and creating a new color conversion table. 12. The apparatus according to claim 11, wherein said color conversion table storage means stores a first profile representing a conversion relationship between said color data D and colorimetric data; A second profile storage unit for storing a second profile representing a conversion relationship between color data and the color data D '. 13. The apparatus according to claim 12, wherein the first profile is a profile set corresponding to a printing condition of a printing press, and the second profile is set corresponding to an output condition of a printer. A color conversion table creation device, characterized in that the profile is a profile to be created. 14. The first device converts image data consisting of color data D processed by a first device into image data consisting of color data D 'processed by a second device using a color conversion table. A proof creating apparatus for creating a proof of an image created by the second device by using the second device; and a constraint condition setting means for setting a constraint condition; A color conversion table creating means for creating a color conversion table between the remaining color data D and D 'in a colorimetric manner while creating the color conversion table based on the condition; Color conversion means for converting the color data D into the color data D 'using a color conversion table; and a proof for outputting the proof based on the color data D' A proof creation device, comprising: 15. An apparatus according to claim 14, wherein said constraint condition setting means comprises: constraint condition storage means for storing various constraint conditions; and constraint condition selection means for selecting a desired constraint condition from said constraint condition storage means. Means, and a proof creating device. 16. An apparatus according to claim 14, further comprising: a color conversion table storing means for storing a color conversion table corresponding to a colorimetric relationship between all the color data D and D '; The proof creating apparatus changes the color conversion table based on the constraint condition and creates a new color conversion table. 17. An apparatus according to claim 14, wherein said proof output means is a printer.