TWI783774B - Prediction method of pigment color matching ratio - Google Patents

Abstract

A method for predicting the color matching ratio of pigments includes the following steps: obtaining a first reflection spectrum of a first pigment, and obtaining a second reflection spectrum of a second pigment. A plurality of first structured reflection spectra are obtained by calculating according to a plurality of different ratios of the first reflection spectrum and the second reflection spectrum, and each of the first construction reflection spectra has a corresponding pigment color matching ratio. Obtain a reflectance spectrum of one of the pigments to be tested. From the first constructed reflectance spectra, find out the first constructed reflectance spectrum which is the same as or the closest to the reflectance spectrum of the pigment to be tested. The corresponding color matching ratio of the pigment is obtained according to the found reflection spectrum of the first structure. That is, the color matching ratio of the pigment can be used as a reference value, and the ratio of the two pigments can be adjusted to save time and material costs.

Description

Prediction method of pigment color matching ratio

The present invention is related to the color matching of pigments; in particular, it refers to a method for predicting the color matching ratio of pigments.

The human eye's perception of color is mainly produced by three kinds of cone cells on the color retina after being stimulated by external light. Pigments of different colors have different selective absorption and reflection on the spectrum. Taking green pigments as an example, they are generally obtained by adding cyan pigments to yellow pigments, and the interpretation of the spectrum is that yellow pigments absorb more blue-violet bands, while The cyan pigment absorbs more orange-red bands, and after mixing the two, only the green band will have a strong reflection, which is the reason for the final green color.

Take the color matching of plastic pigments as an example. After receiving an order for plastic pigments of a specific color, manufacturers usually need to make a large number of samples first. Each sample is mixed with at least two colors of pigments, and then mixed with the plastic pigments ordered. Color comparison to find the most identical or closest formula. The ratio of the color matching of the samples depends on the experience of the personnel. For experienced personnel, they can choose the appropriate ratio based on past experience, and the number of samples produced is small; but for inexperienced personnel, they can only choose Various proportioning samples are made, and the number of samples produced is relatively large. Therefore, the conventional method of color matching of pigments will consume a lot of labor costs and material costs.

In view of this, the purpose of the present invention is to provide a method for predicting the color matching ratio of pigments, which can provide a better color matching ratio of pigments as a reference.

In order to achieve the above object, a method for predicting the ratio of color matching of pigments provided by the present invention comprises the following steps:

A. Obtaining a first reflection spectrum of a first pigment, and obtaining a second reflection spectrum of a second pigment, wherein the first pigment is different in color from the second pigment;

B. Calculate a plurality of first construction reflection spectra according to a plurality of different ratios of the first reflection spectrum and the second reflection spectrum; each of the first construction reflection spectra has a corresponding pigment color matching ratio;

C. Obtain a reflectance spectrum of a pigment to be measured;

D. Find the first constructed reflectance spectrum that is the same as or the closest to the reflectance spectrum of the pigment to be tested from the first constructed reflectance spectra;

E. Obtain a corresponding color matching ratio of the pigment according to the found reflection spectrum of the first structure.

The effect of the present invention is that the color matching ratio of the first pigment and the second pigment required by the pigment to be tested can be predicted, and a better pigment can be obtained without spending a lot of samples, manpower and time required by the traditional method The color matching ratio is used as a reference value for personnel color matching.

In order to illustrate the present invention more clearly, preferred embodiments are given and detailed descriptions are given below in conjunction with drawings. Please refer to Fig. 1, which is a flow chart of a method for predicting the color matching ratio of a preferred embodiment of the present invention, which is used to predict the color matching ratio of a pigment to be tested by mixing two kinds of pigments. The method for predicting the color matching ratio of the pigment comprises the following steps:

Step S1: As shown in FIG. 2, obtain a first reflection spectrum 10 of a first pigment, and obtain a second reflection spectrum 20 of a second pigment, wherein the first pigment is different from the second pigment in color , for example, the plastic pigment whose first color is white, its CIE1931 xy chromaticity coordinates are x=0.32, y=0.34; the plastic pigment whose second color is yellow, its CIE1931 xy chromaticity coordinates are x=0.44, y =0.47. Plastic pigments may for example be PVC pigments. In this embodiment, a spectrometer is used to measure and record the first reflection spectrum 10 and the second reflection spectrum 20 of the first pigment and the second pigment, for example, in a database. The spectrometer used in this embodiment The light source is D65 standard light source.

Step S2: Calculate and obtain a plurality of first constructed reflectance spectra 30 according to a plurality of different ratios of the first reflectance spectrum 10 and the second reflectance spectrum 20 . Each of the first constructed reflectance spectra 30 has a corresponding pigment color matching ratio. In this embodiment, the first constructed reflection spectra 30 are obtained by interpolating the first reflection spectrum 10 and the second reflection spectrum 20 and recorded in the database. As shown in FIG. 2, these first constructed reflectance spectra 30 are interpolated according to the reflectance of the first reflectance spectrum 10 and the reflectance of the second reflectance spectrum 20 in each wavelength, to obtain the first reflectance spectrum Nine first constructed reflectance spectra 30 between 10 and second reflectance spectrum 20 . The first first reflection spectrum 30 on the top is the ratio of the first reflection spectrum 10 to the second reflection spectrum 20 is 0.9:0.1, that is, the reflectance of the first first construction reflection spectrum 30 is the first reflection spectrum The reflectance of 10 is multiplied by 0.9 and the reflectance of the first reflection spectrum 10 is multiplied by 0.1. The second first construction reflection spectrum 30 is the ratio of the first reflection spectrum 10 to the second reflection spectrum 20 is 0.8:0.2, and so on, the ninth first construction reflection spectrum 30 at the bottom is the first The ratio of the reflection spectrum 10 to the second reflection spectrum 20 is 0.1:0.9. In this way, the reflectance of the first structured reflection spectra 30 is changed in equal proportions between the reflectance of the first reflection spectrum 10 and the reflectance of the second reflection spectrum 20. In one embodiment, it can also be for unproportional changes.

In this embodiment, the color matching ratio of the pigments corresponding to the first structured reflectance spectra 30 is the difference ratio between the first pigment and the second pigment.

The number of the first constructed reflectance spectra 30 is not limited to nine, and the ratio of the first reflective spectrum 10 to the second reflective spectrum 20 of each first constructed reflective spectrum 30 is not limited to 0.9:0.1 to 0.1:0.9.

The pigment color matching ratio corresponding to each first constructed reflection spectrum 30 can be preset, and the setting steps include:

The first pigment and the second pigment are mixed in different predetermined ratios to obtain a plurality of sample pigments, and the colors of the sample pigments are different, and the color of the sample pigments is between the first color and the second color. between.

One reflectance spectrum of each of the sample pigments was taken. In this embodiment, a spectrometer is used to measure and record the reflectance spectra of these sample pigments, for example, in a database. The measurement of the first pigment, the second pigment and these sample pigments can be performed in advance, and the respective reflectance spectra can be recorded for use.

Find the reflection spectrum of the sample pigment that is the same as or most similar to each of the first construction reflection spectra 30, and set the predetermined ratio corresponding to the reflection spectrum of the found sample pigment to correspond to each of the first construction reflection spectra 30 The color ratio of the paint.

In this embodiment, the reflectance spectra of the first constructed reflectance spectra 30 and the sample pigments are converted into chromaticity coordinates, and according to the chromaticity coordinates of the first constructed reflective spectra 30 and the reflectances of the sample pigments Spectra are compared to find the same or most similar reflectance spectra. In this embodiment, the first construction reflectance spectrum 30 and the reflectance spectrum of the sample pigment are respectively converted into CIE 1931 XYZ tristimulus values, and after normalization, the CIE 1931 xy chromaticity coordinates can be obtained. Furthermore, the CIE 1931 xy chromaticity coordinates are converted into CIE 1976 L*a*b* chromaticity coordinates, and the chromaticity coordinates are used for comparison to find out the sample pigments that are the same or most similar to each first constructed reflectance spectrum 30 the reflectance spectrum. The closer the distance between the two chromaticity coordinates (that is, the smaller the comprehensive color difference value ΔE*), the more similar the reflection spectrum is. In one embodiment, the CIE 1931 xy chromaticity coordinates can also be used for comparison to find the reflectance spectrum of the sample pigment that is the same as or most similar to each first constructed reflectance spectrum 30 .

For example, as shown in FIG. 2, the ratio of the first reflection spectrum 10 to the second reflection spectrum 20 of the sixth first reflection spectrum 30 (the first construction reflection spectrum 30 indicated by the arrow) is 0.4: 0.6, after converting to CIE 1976 L*a*b* chromaticity coordinates, the reflectance spectrum 402 of the sample pigment mixed with the first pigment and the second pigment at a predetermined ratio of 10:1 is obtained (dashed line ) is the closest, then set the pigment color matching ratio corresponding to the sixth first construction reflectance spectrum 30 to 10:1.

As another example, as shown in FIG. 3 , the ratio of the first reflection spectrum 10 to the second reflection spectrum 20 of the seventh first construction reflection spectrum 30 (the first construction reflection spectrum 30 indicated by the arrow) is 0.3:0.7. After conversion to CIE 1976 L*a*b* chromaticity coordinates, the reflection spectrum 404 (shown by the dotted line) of the sample pigment mixed with the first pigment and the second pigment at a predetermined ratio of 5:1 is obtained. If it is similar, the pigment color matching ratio corresponding to the seventh first construction reflectance spectrum 30 is set to 5:1.

The setting method of the color matching ratio of other pigments corresponding to the first constructed reflectance spectrum 30 is the same and will not be repeated here.

Through the above setting steps, the color matching ratio of the pigment corresponding to each first constructed reflectance spectrum 30 can be obtained. Next, the steps of the method for predicting the color matching ratio of the pigments in this embodiment will be described.

Step S3: Obtain a reflectance spectrum of the pigment to be tested; in this embodiment, a spectrometer is used to measure and record the reflectance spectrum of the pigment to be tested, for example, in a database. In this embodiment, the color of the pigment to be tested is between the first color and the second color, but the pigment matching ratio between the first color and the second color is unknown.

Step S4: Find the first constructed reflectance spectrum 30 that is the same as or closest to the reflectance spectrum of the pigment to be tested from among the first constructed reflectance spectra 30 . In this embodiment, the chromaticity coordinates corresponding to the reflectance spectrum of the pigment to be tested are compared with the chromaticity coordinates corresponding to the first constructed reflectance spectra to find the A reflectance spectrum similar to that of the first construction. For example, compare with CIE 1976 L*a*b* chromaticity coordinates. In one embodiment, CIE 1931 xy chromaticity coordinates can also be used for comparison.

Step S5: Obtain a corresponding color matching ratio of the pigment according to the found first constructed reflectance spectrum 30 .

For example, as shown in Figure 4, in step S4, the reflectance spectrum 50 (shown by the dotted line) of the pigment to be tested is converted into the comparison of the CIE 1976 L*a*b* chromaticity coordinates, and it is compared with the ninth The first constructed reflectance spectrum 30 is the closest, and the pigment color matching ratio corresponding to the ninth first constructed reflective spectrum 30 is 1:1. Afterwards, in step S5 , the pigment color matching ratio (1:1) corresponding to the ninth first construction reflectance spectrum 30 can be obtained and recorded in the database.

Through the above steps, it can be predicted that the pigment to be tested should be able to be mixed with the corresponding pigment color matching ratio (1:1) from the first pigment and the second pigment. When the personnel want to mix the pigment with the same color as the pigment to be tested, the predicted color matching ratio of the pigment can be used as a reference value, that is, the first pigment and the second pigment are mixed at a ratio of 1:1. There is still a slight error in the measurement of the pigment, and it is only necessary to fine-tune the mixing ratio. Thereby, the time cost and material cost of many times of wrong attempts can be saved.

The above are the main steps of the method for predicting the color matching ratio of pigments. The method for predicting the color matching ratio of pigments in this embodiment may further include the following steps S6-S10 to predict the result of mixing a third pigment and a fourth pigment for another pigment to be tested. The required color matching ratio.

Step S6: As shown in FIG. 5, obtain a third reflection spectrum 60 of the third pigment, and obtain a fourth reflection spectrum 70 of a fourth pigment, as recorded in the database, wherein the third pigment and The colors of the fourth pigments are different. In this embodiment, both the color of the third pigment and the color of the first pigment are white plastic pigments; the fourth pigment is orange plastic pigment, and its CIE1931 xy chromaticity coordinates are x=0.50, y=0.43. Plastic pigments may for example be PVC pigments.

Step S7: Calculate and obtain a plurality of second constructed reflectance spectra 80 according to a plurality of different ratios of the third reflected spectrum 60 and the fourth reflected spectrum 70 (only the sixth second constructed reflected spectrum 80 is shown in FIG. 5 ), The number of the second construction reflection spectra 80 is the same as the number of the first construction reflection spectra, and each of the second construction reflection spectra 80 is set to have the same color ratio of the pigment as each of the first construction reflection spectra, the These second constructed reflectance spectra 80 are recorded in a database. In this embodiment, the construction method of the second constructed reflectance spectra 80 is the same as that of the first constructed reflective spectra 30 in step S2, that is, the third reflective spectrum 60 and the fourth reflective spectrum 70 are used to construct Nine second constructed reflectance spectra 80 are obtained through interpolation calculation, and the ratios of the third reflective spectrum 60 and the fourth reflective spectrum 70 of the nine second constructed reflective spectra 80 are 0.9:0.1 to 0.1:0.9 respectively. The color matching ratios of the pigments corresponding to the second structured reflectance spectra 80 are also set to be the same as the color matching ratios corresponding to the first constructed reflective spectra. The number of the second structured reflectance spectra 80 is not limited to nine, and the ratio of the third reflective spectrum 60 to the fourth reflective spectrum 70 of each second structured reflective spectrum 80 is not limited to 0.9:0.1 to 0.1:0.9.

Step S8: Acquiring a reflectance spectrum of another pigment to be tested. The color of the pigment to be tested is between the third color and the fourth color, but the pigment matching ratio between the third color and the fourth color is unknown.

Step S9: Find the second constructed reflectance spectrum 80 which is the same as or the closest to the reflectance spectrum of the other pigment to be tested from the second constructed reflectance spectra 80 . In this embodiment, the chromaticity coordinates corresponding to the reflectance spectrum of another pigment to be measured are compared with the chromaticity coordinates corresponding to the second constructed reflectance spectrum 80 to find out the reflectance of the other pigment to be measured. A second constructed reflectance spectrum 80 with the same or closest spectrum. For example, compare with CIE 1976 L*a*b* chromaticity coordinates. In one embodiment, CIE 1931 xy chromaticity coordinates can also be used for comparison.

Step S10 : Obtain a corresponding color matching ratio of the pigment according to the found second constructed reflectance spectrum 80 .

For example, as shown in Figure 5, in step S9, the reflectance spectrum 90 (shown by the dotted line) of the other pigment to be tested is converted into CIE 1976 L*a*b* chromaticity coordinates for comparison, and its With the second construction reflection spectrum 80 of the sixth article, the ratio of the third reflection spectrum 60 and the fourth reflection spectrum 70 of the sixth second construction reflection spectrum 80 is 0.4:0.6, and the corresponding pigment color matching ratio is 10: 1. Afterwards, in step S10 , the pigment color matching ratio (10:1) corresponding to the sixth second constructed reflectance spectrum 80 can be obtained.

Thereby, it can be predicted that another pigment to be tested should be mixed with the third pigment and the fourth pigment in the corresponding pigment color matching ratio (10:1). When personnel want to mix a pigment with the same color as another pigment to be tested, the color matching ratio of the pigment can be used as a reference value, that is, the third pigment and the fourth pigment are mixed at a ratio of 10:1. There is still a slight error in the other pigment to be tested, and it is only necessary to fine-tune the mixing ratio. The time cost and material cost of multiple false attempts can also be saved.

The above description is only a preferred feasible embodiment of the present invention, and all equivalent changes made by applying the description of the present invention and the scope of the patent application should be included in the scope of the patent of the present invention.

10: First reflection spectrum 20: Second reflection spectrum 30: First Construct Reflectance Spectrum 402: Reflection Spectrum 404: Reflection Spectrum 50: reflection spectrum 60: Third reflection spectrum 70: Fourth reflection spectrum 80:Second Construction Reflectance Spectrum 90: Reflection Spectrum

Fig. 1 is a flow chart of a method for predicting the color matching ratio of pigments in a preferred embodiment of the present invention. Fig. 2 is a graph of the reflectance spectrum of the above-mentioned preferred embodiment of the present invention. Fig. 3 is a graph of the reflectance spectrum of the above-mentioned preferred embodiment of the present invention. Fig. 4 is a graph of the reflectance spectrum of the above-mentioned preferred embodiment of the present invention. Fig. 5 is a graph of the reflectance spectrum of the above-mentioned preferred embodiment of the present invention.

Claims (7)

A method for predicting the ratio of color matching of pigments, comprising the following steps: A. Obtaining a first reflection spectrum of a first pigment, and obtaining a second reflection spectrum of a second pigment, wherein the first pigment is different in color from the second pigment; B. Calculate a plurality of first construction reflection spectra according to a plurality of different ratios of the first reflection spectrum and the second reflection spectrum; each of the first construction reflection spectra has a corresponding pigment color matching ratio; C. Obtain a reflectance spectrum of a pigment to be tested; D. Find the first constructed reflectance spectrum that is the same as or the closest to the reflectance spectrum of the pigment to be tested from the first constructed reflectance spectra; E. Obtain a corresponding color matching ratio of the pigment according to the found reflection spectrum of the first structure. The method for predicting the color matching ratio of a pigment according to Claim 1, wherein in step B, the first constructed reflectance spectra are obtained by interpolating the first reflective spectrum and the second reflective spectrum. The method for predicting the color matching ratio of the pigment according to claim 2, wherein the reflectance of the first constructed reflectance spectrum in step B is equal to the reflectance of the first reflectance spectrum and the reflectance of the second reflectance spectrum Variety. The method for predicting the color matching ratio of pigments as described in claim 1 includes a setting step for setting the color matching ratio of pigments corresponding to each of the first constructed reflection spectra; wherein, the setting step includes: Mixing the first pigment and the second pigment in different predetermined ratios to obtain a plurality of sample pigments, and the colors of the sample pigments are different; Obtain one reflectance spectrum of each of the sample pigments; finding the reflectance spectrum of the sample pigment that is the same as or most similar to each of the first constructed reflectance spectra, and setting a predetermined ratio corresponding to the reflectance spectrum of the found sample pigment as the pigment corresponding to each of the first constructed reflectance spectra Color ratio. The method for predicting the color matching ratio of pigments as described in claim 4, wherein after step E, it further includes, Obtaining a third reflection spectrum of a third pigment, and obtaining a fourth reflection spectrum of a fourth pigment, wherein the third pigment is different in color from the fourth pigment; A plurality of second structured reflection spectra are obtained by calculating a plurality of different ratios of the third reflection spectrum and the fourth reflection spectrum, and the number of the second construction reflection spectra is the same as the number of the first construction reflection spectra, and Setting each of the second construction reflectance spectra to have the same color ratio of the pigment as each of the first construction reflection spectra; Obtain one of the reflection spectra of another pigment to be measured; Finding the second constructed reflectance spectrum that is the same as or closest to the reflectance spectrum of the other pigment to be tested from the second constructed reflectance spectra; A corresponding color ratio of the pigment is obtained according to the found reflection spectrum of the second structure. The method for predicting the color matching ratio of pigments as described in claim 1, wherein in step D, the chromaticity coordinates corresponding to the reflectance spectrum of the pigment to be tested are compared with the chromaticity coordinates corresponding to the first constructed reflectance spectra to find out The reflectance spectrum of the first construction is the same as or the closest to the reflectance spectrum of the pigment to be tested. The method for predicting the color matching ratio of pigments as described in claim 1, wherein the color matching ratios of the pigments corresponding to the first constructed reflectance spectra are the different ratios of the first pigment and the second pigment.

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