Method of Testing the Color Quality of a Colored Gemstone

Abstract

A method of testing the color quality of a colored gemstone is disclosed, taking the gem color as an entirety visually composed of different color components, whose total amount of color components is constant, so as to calculate hue-purity, color-strength and relative chromaticity of the gem color to test the color quality. The method comprises the following steps: (1) determining blackness, chromaticness and hue of the gem color; (2) calculating the hue-purity, color-strength and relative chromaticity in accordance with the blackness, chromaticness and hue; (3) finding a matching color in a pre-established standard color library for this specific gemstone according to the hue-purity, color-strength and relative chromaticity calculated in step (2), and use the name of the matching color to indicate the gem color and color quality.

Claims

1. A method of establishing a standard color library for a colored gemstone for testing the color quality of the colored gemstone, comprising: taking the color of the colored gemstone as an entirety visually composed of different color components, whose total amount of color components is constant, so as to calculate hue-purity, color-strength and relative chromaticity of said color to establish said standard color library for said colored gemstone, the steps are as follows: (1) collecting a plurality of colored gemstone samples as a training set; (2) determining blackness, chromaticness and hue of the color of said colored gemstone samples in said training set in a standard environment, wherein said color components include colored components and a white visual component, wherein said colored components include a black visual component and all chromatic visual components, wherein said blackness is the percentage content of said black visual component in said color of said colored gemstone, wherein said chromaticness is the percentage content of said chromatic visual components in said color of said colored gemstone; (3) calculating said hue-purity, said color-strength and said relative chromaticity of said color of said colored gemstone samples according to said blackness, said chromaticness and said hue: wherein said hue-purity represents the degree of purity or impurity and the offset color of said hue of said color of said colored gemstone calculated on the basis of one of the four psychophysical primary colors which are red, green, yellow, blue and the transitional intermediate colors between non-opposing psychophysical primary colors, using one of the following two calculation methods: (a), hue-purity is x % the secondary psychological primary color to the main psychological primary color, wherein x % is the percentage proportion of the secondary psychological primary color in the hue; and (b), hue-purity is y % the main psychological primary color to the transitional intermediate color, wherein y % is half of the difference between the percentage proportion of the main psychological primary color in the hue and the percentage proportion of the secondary psychological primary color in the hue; wherein: said main psychological primary color means the psychological primary color whose percentage proportion in said hue is more than 50%, and said secondary psychological primary color means the psychological primary color whose percentage proportion in said hue is less than 50%; when the percentage proportions of both psychological primary colors in said hue are 50%, then either of the psychological primary colors can be taken as said main psychological primary color, and the other can be taken as said secondary psychological primary color; said transitional intermediate colors are those of any two non-opposing psychological primary colors in the four psychological primary colors; wherein said color-strength is as follows: color-strength=blackness+chromaticness; wherein said relative chromaticity is as follows: relative chromaticity=chromaticness/color-strength; and (4) identifying, classifying, quantifying and defining the specific color represented by each colored gemstone sample in said training set according to said hue-purity, said color-strength and said relative chromaticity calculated in step (3) to get said standard color library for said colored gemstone.

2. The method of establishing a standard color library for a colored gemstone according to claim 1, wherein said blackness, said chromaticness and said hue are directly measured by using a color scan of the Natural Color System or determined by visual comparison between said colored gemstone samples and standard color cards of the Natural Color System.

3. The method of establishing a standard color library for a colored gemstone according to claim 1, wherein said blackness and said chromaticness are respectively equivalent to value B and value C determined by using the Ostwald Color System, and said hue is determined by using the Natural Color System.

4. The method of establishing a standard color library for a colored gemstone according to claim 1, wherein said standard environment is selected from one of a group composed of D50, D55 and D65 standard illumination environments.

5. The method of establishing a standard color library for a colored gemstone according to claim 2, wherein said standard environment is selected from one of a group composed of D50, D55 and D65 standard illumination environments.

6. The method of establishing a standard color library for a colored gemstone according to claim 3, wherein said standard environment is selected from one of a group composed of D50, D55 and D65 standard illumination environments.

7. The method of establishing a standard color library for a colored gemstone according to claim 1, wherein said identifying, classifying, quantifying and defining in said step (4) also includes using natural color nomenclature or said hue to name specific colors represented by said colored gemstone samples.

8. The method of establishing a standard color library for a colored gemstone according to claim 2, wherein said identifying, classifying, quantifying and defining in said step (4) also includes using natural color nomenclature or said hue to name specific colors represented by said colored gemstone samples.

9. The method of establishing a standard color library for a colored gemstone according to claim 3, wherein said identifying, classifying, quantifying and defining in said step (4) also includes using natural color nomenclature or said hue to name specific colors represented by said colored gemstone samples.

10. A method of testing the color quality of a colored gemstone, comprising: taking the color of the colored gemstone as an entirety visually composed of different color components, whose total amount of color components is constant, so as to calculate hue-purity, color-strength and relative chromaticity of said color to test said color quality of said colored gemstone, the steps are as follows: (1) determining blackness, chromaticness and hue of the color of said colored gemstone to be measured in a standard environment, wherein said color components include colored components and a white visual component, wherein said colored components include a black visual component and all chromatic visual components, wherein said blackness is the percentage content of said black visual component in said color of said colored gemstone, wherein said chromaticness is the percentage content of said chromatic visual components in said color of said colored gemstone; (2) calculating said hue-purity, said color-strength and said relative chromaticity of said color of said colored gemstone to be tested according to said blackness, said chromaticness and said hue: wherein said hue-purity represents the degree of purity or impurity and the offset color of said hue of said color of said colored gemstone calculated on the basis of one of the four psychophysical primary colors which are red, green, yellow, blue and the transitional intermediate colors between non-opposing psychophysical primary colors, using one of the following two calculation methods: (a), hue-purity is x % the secondary psychological primary color to the main psychological primary color, wherein x % is the percentage proportion of the secondary psychological primary color in the hue; and (b), hue-purity is y % the main psychological primary color to the transitional intermediate color, wherein y % is half of the difference between the percentage proportion of the main psychological primary color in the hue and the percentage proportion of the secondary psychological primary color in the hue; wherein: said main psychological primary color means the psychological primary color whose percentage proportion in said hue is more than 50%, and said secondary psychological primary color means the psychological primary color whose percentage proportion in said hue is less than 50%; when the percentage proportions of both psychological primary colors in said hue are 50%, then either of the psychological primary colors can be taken as said main psychological primary color, and the other can be taken as said secondary psychological primary color; said transitional intermediate colors are those of any two non-opposing psychological primary colors in the four psychological primary colors; wherein said color-strength is as follows: color-strength=blackness+chromaticness; wherein said relative chromaticity is as follows: relative chromaticity=chromaticness/color-strength; and (3) finding a matching color in a pre-established standard color library for this specific colored gemstone according to said method mentioned in claim 1 based on said hue-purity, said color-strength and said relative chromaticity calculated in step (2), and using the name of the matching color to indicate said color and said color quality of said colored gemstone to be tested.

11. The method of testing the color quality of a colored gemstone according to claim 10, wherein said blackness, said chromaticness and said hue are directly measured by using a color scan of the Natural Color System or determined by visual comparison between said colored gemstone sample and standard color cards of the Natural Color System.

12. The method of testing the color quality of a colored gemstone according to claim 10, wherein said blackness and said chromaticness are respectively equivalent to value B and value C determined by using the Ostwald Color System, and said hue is determined by using the Natural Color System.

13. The method of testing the color quality of a colored gemstone according to claim 10, wherein said standard environment is selected from one of a group composed of D50, D55 and D65 standard illumination environments.

14. The method of testing the color quality of a colored gemstone according to claim 11, wherein said standard environment is selected from one of a group composed of D50, D55 and D65 standard illumination environments.

15. The method of testing the color quality of a colored gemstone according to claim 12, wherein said standard environment is selected from one of a group composed of D50, D55 and D65 standard illumination environments.

Description

DETAILED DESCRIPTION

[0046] The following is a further description of the application in accordance with the preferred embodiments.

[0047] Principles of the method of testing the color quality of a colored gemstone provided in this application are as follows:

[0048] The more vivid the color of a colored gemstone, the better the color quality, the method of testing the color quality of a colored gemstone provided in this application takes the color of the colored gemstone as an entirety visually composed of different color components, whose total amount of color components is constant, so as to calculate hue-purity, color-strength and relative chromaticity of the color of the colored gemstone, and test the color quality by calibrating the vividness of the gem color with the hue-purity, color-strength and relative chromaticity. Wherein, the color components include colored components and a white visual component; the colored components include a black visual component and all chromatic visual components, which is opposite to the white visual component. Wherein, hue-purity is the purity of the hue of the color of the colored gemstone; color-strength is the strength of the colored components in the color of the colored gemstone; relative chromaticity is used to describe the relative degree of purity of the chromatic visual components of colors with similar hue-purity and color-strength or the relative vividness of a color in similar colors, in which the similar hue-purity refers to the same color components contained in the hue and the percentage proportion of the contained color components are within a predetermined range, the similar color-strength refers to the color-strength within a predetermined range, the similar colors refer to the colors with similar hue-purity and color-strength. The three quality testing indexes (hue-purity, color-strength and relative chromaticity) constitute a complete color quality testing system, namely, the higher the hue-purity, color-strength and relative chromaticity of the color, the more vivid the gem color and the better the color quality.

[0049] In order to better explain concepts and measurement methods of the hue-purity, color-strength and relative chromaticity, the following is a further explanation, comparing them with the three elements of color in the HV/C nomenclature, saturation and vividness:

[0050] The hue in the three elements of color is used to describe the chromatic appearance of a color such as red, orange, yellow, green, cyan, blue and purple, etc.; while neutral colors such as black, white and gray have no hue. In the HV/C nomenclature, hue is indicated by a specific notation of the system, for example, in the Munsell Color System, 2.5G indicates a yellowish green, 10BG indicates a bluish green, and 5PB indicates a blue, etc. However, in this application, hue-purity focuses on the identification of relative difference of similar hues (refer to the same color components contained in the hue and the percentage proportions of the contained color components are within a predetermined range), and the quality of the color of a colored gemstone is tested and indicated by calculating the purity or impurity and the offset color of the hue of the color of the colored gemstone with a specific color as a reference, for example, whether the red of ruby is pure or impure (with or without an offset color), yellowish or bluish, and how pure or impure the hue is. The meanings of the two are not the same, and thus the measurements and indications are also different.

[0051] In the three elements of color, lightness is used to describe the lightness or darkness of a color. Modern color order systems usually set the lightness of pure black to 0, the lightness of pure white to 10, and divide it into a total of 11 levels according to perceived equidistance, the greater the lightness, the brighter the color, the smaller the lightness, the darker the color. Chroma is used to describe the intensity of the chromatic stimulus of a color, and neutral colors such as black, white and gray have no chroma. In the HV/C nomenclature, chroma is measured as the departure degree of a color from the neutral color of the same lightness according to perceived equidistance. The maximum intensity of the chromatic stimulus of colors with different hues (namely, the intensity of the chromatic stimulus of pure chromatic colors with different hues) and the maximum intensity of the chromatic stimulus of colors with the same hue but different lightness are different, so the chroma range and maximum chroma of each hue and lightness are different. For example, in the Munsell Color System, the maximum chroma of most hues is more than a dozen and some can reach twenty. In the method presented in this application, color-strength is a concept of color in psychology generated by the concept of concentration in analogy physics, which is used to describe the intuitive characteristic of strong or weak gem color. It only makes sense to understand and measure the color as a whole, the darker, the more colorful, the stronger, the whiter the weaker; in other words, black, gray and all chromatic colors can increase the strength of color on psychological feeling, while white will reduce the strength. Obviously, this color-strength and the chroma in the three elements of color refer to two different things, and it is significantly different from lightness. For example, in people's common sense and experience, the strength of dark blue of a sapphire which is close to black is very strong, but its lightness and chroma are very low.

[0052] Due to the color characteristics described by lightness, chroma in the HV/C nomenclature and the so-called saturation have a certain similarity with the vividness in people's common sense and experience, some research directly makes equivalent substitution between lightness, chroma, saturation and vividness, and even regards lightness, chroma and saturation as vividness. However, this is not true as a matter of fact:

[0053] Saturation in fact is a concept borrowed from physics. In physics, when solute concentration in a solution reaches the maximum, the solution is then saturated, and the maximum concentration of the solute in unit solution is then called saturation of the solute in the solution, which is essentially a concentration concept (concentration threshold or equivalent to concentration). However, in chromatics, the meaning of saturation is much more complex and not so exact. In fact, saturation is not an inherent and normative concept of color in the HV/C nomenclature; it is used to describe color characteristics because it is easy to understand and can facilitate the need of practical application to replace chroma of color, purity of colored light or concentration or purity of pigment in ideographic comparison. For example, in the TV industry, the purity of the spectral color is set as the saturation point of purity of the colored light with the same dominant wavelength, so at this time, saturation can be equivalent to the purity of colored light. Another example is that in the art industry or printing industry, saturation is used to indicate the concentration or purity of a pure pigment in a mixed pigment, so as to facilitate pigment mixing. When there is only one pure chromatic pigment excluding black, gray and white pigment in the mixed pigment, the so-called saturation can be equivalent to chroma. If however there is also a variety of chromatic pigments or when the chromatic pigment is impure, then saturation is the concentration or purity in common meaning and it is totally different from chroma. In practical application, unless otherwise specified, saturation usually refers specifically to the saturation of spectral color in color, and colors saturated are usually the most vivid, therefore, this can easily lead to the inertia illusion that the more saturated the color, the more vivid the color, and that saturation is vividness; this can even lead to the fallacy that saturation must be chroma, because saturation is the concept of concentration in essence, chroma is then vividness or concentration of the color. As a matter of fact, saturation can be equivalent to chroma in analogy concept only under certain circumstances, and it cannot directly reflect the vividness of a color.

[0054] However, from the perspective of the three elements of color, vividness is actually related to hue, lightness and chroma. Colors of different hues with the maximum chroma have different vividness; for colors of the same hue, it is not the higher the chroma, the more vivid the color. This is because vividness depends not only on chroma but also on lightness, to say it in a common way, colors with the same hue and chroma may be blackish or may be whitish, thus exhibiting different vividness. Therefore, chroma or so-called saturation cannot be equivalent to vividness or measure vividness in linearity.

[0055] Lightness also should not be confused with vividness, for any color, the closer it is to white, the greater the lightness is; lightness of pure white is the maximum but it is obviously not the most vivid. Actually, there is no direct or necessary link between lightness and vividness, and thus it is difficult to use lightness, chroma and hue, namely, the three elements of color, to clearly calibrate and reflect the vividness of a color and its variation: the greater the lightness, the brighter the color, it is whitish if it is too bright; the smaller the lightness, the darker the color, it is blackish if it is too dark, vividness of the color will be reduced if the color is whitish or blackish, and the whitish color may not be more vivid than the blackish color or the blackish color may not be more vivid than the whitish color. In other words, the linear change of lightness of colors with the same hue and chroma does not cause the corresponding linear change of vividness. In fact, the chroma or vividness can only be at the maximum level when the lightness is moderate. However, the lightness of colors of different hues with the maximum chroma (namely the appropriate lightness) is different, lightness of some hues must be greater to achieve the maximum chroma while some must be smaller to achieve the maximum chroma, which cannot be derived by simply using the exact logical relationship (it is impractical that the identification or comparison is subject to suitability). Because of this uncertain relationship, lightness in fact does not have objective significance for identification of vividness. In addition, different hues or different lightness values have different chroma ranges, and different chroma values have different lightness ranges, it is difficult for ordinary people to understand and grasp the use of the three elements of color to test and indicate the vividness of gem color.

[0056] In order to objectively reflect the varying regularity of vividness of gem color, the method of testing the color quality of a colored gemstone provided in this application is to use a psychological research method to take the color of the colored gemstone as an entirety visually composed of different color components (wherein said color components include a white visual component, a black visual component and all chromatic visual components), whose total amount of color components is constant, so as to simulate solute with colored components including the black visual component (Note: gray is the color presented after black is diluted, so it is no longer regarded as a mere visual component and is included in the black visual component.) and all chromatic visual components, simulate solvent with the white visual component and simulate solution with all color components to calculate the percentage content of the colored components in the color, namely, the strength of the gem color on psychological feeling. It is also a way to calculate the ratio between chromatic visual components and colored components, namely, the relative chromaticity which identifies and indicates the color quality of the colored gemstone according to the changing relationship between the chromatic visual components and the black visual component in the certain total amount of colored components. And then use the three quality indexes, the hue-purity, color-strength and relative chromaticity to calibrate the relative vividness of the gem color in similar colors. In other words, vividness is actually a concept in a relative meaning rather than in an absolute meaning, while relative chromaticity only makes sense when compared in similar colors with same or similar hue-purity and color-strength.

[0057] For colors with the same or similar hue-purity and color-strength, the greater the relative chromaticity, the higher the proportion of the chromatic visual components in the colored components, the less the proportion of the black visual component, and the more vivid the color, take ruby as an example, there are subtle differences in quality between different pigeon's blood, pigeon's blood with a lower relative chromaticity appears darker because of its relatively deeper color, resulting in low vividness and quality. For colors with different hue-purity such as the purple, green, yellowish green and bluish green of jadeite, or for colors with the same or similar hue-purity but different color-strength such as the apple green, spicy green and dark green of jadeite, significant differences in hue-purity or color-strength lead to different aesthetic beauty, market diversification color aesthetic and value orientation, so it is not particularly meaningful to compare the vividness of colors by relative chromaticity, and the quality of colors can be visually indicated and differentiated by the color names quantified and defined by the hue-purity, color-strength and relative chromaticity.

[0058] The above comparison shows that, when compared to the three elements of color, the hue-purity, color-strength and relative chromaticity in this application places emphasis more on integrity and logic. However, the three elements of color are more independent of each other, each is measured by an independent method, and there is no clear logical link between them, they tend to be three separate characteristic quantities, and thus are not suitable to calculate the hue-purity, color-strength and relative chromaticity in this application. Therefore, this application uses the Natural Color System with stronger logical relationships in color based on a psychology color research method to measure the color parameters (hue, chromaticness and blackness) in order to calculate the hue-purity, color-strength and relative chromaticity.

[0059] Developed from the Opponent Color Theory by Ewald Hering, the Natural Color System (NCS) is a color order system built on the basis of people's physiological vision and describes color by using color similarity relationships. It uses purely sensual, visual similarity relationships to describe the color, so it is referred to as a psychology method, while the HV/C nomenclature using the three elements of color to describe the color is more physical. Hue, chromaticness, blackness and whiteness used to describe the color are referred to as psychological quantities so as to be distinguished from the three elements of color (psychophysical quantities). According to the Opponent Color Theory, the human visual system consists of a total of six basic color visions which are inherent and not similar to each other, namely, two achromatic colors (black versus white) and four psychophysical primary colors (red versus green, yellow versus blue), and any color in color perception can be similar to the two achromatic colors (black and white) and at most two non-opposing psychophysical primary colors. In the Natural Color System, the NCS notation S sscc-AB systematically describes the color by using the similarity relationships between color and six visual reference colors, namely, the visual components of the color in color perception: the blackness ss indicates the degree of similarity between the color and pure black, namely, the percentage content of the black visual component in color perception; the whiteness (100-ss-cc) indicates the degree of similarity between the color and pure white, namely, the percentage content of the white visual component in color perception; the chromaticness cc indicates the degree of similarity between the color and pure chromatic color with same hue, namely, the percentage content of the chromatic visual components in color perception; the percentage of chromatic visual components AB indicates the hue of the color, namely, 100- and indicate the degree of similarity between the hue and psychophysical primary color A and B, or the percentage proportions of the psychophysical primary color A and B in the chromatic visual components in color perception.

[0060] The Natural Color System quantifies the color into a constant visually composed of a black visual component, a white visual component and chromatic visual components and can be logically derived with a mathematical formula, therefore, it is very suitable for the measurement and calculation of the hue-purity, color-strength and relative chromaticity in this application: determine the blackness, chromaticness and hue of a gem color with the NCS first, take the inherent four psychological primary colors in people's visual system (red, green, yellow and blue) as a reference, and then simply take the secondary psychological primary color and its percentage proportion in the hue as the offset color and the impurity of the hue, thus the hue-purity of the gem color can be obtained; by combining the blackness and chromaticness, the color-strength can be calculated; while relative chromaticity can be calculated by dividing chromaticness into color-strength. In addition to using the four psychological primary colors, we can also use the transitional intermediate color between two non-opposing psychological primary colors included in the hue of the gem color as a reference to calculate and indicate the hue-purity of the gem color. For example, the transitional intermediate color between yellow and red is orange (visually mixed together by the two psychological primary colors, yellow and red), its hue-purity can be indicated as y % yellow to orange, y % red to orange; and the transitional intermediate color between red and blue is purple (visually mixed together by the two psychological primary colors, red and blue), its hue-purity can be indicated as y % blue to purple, y % red to purple. When calculating the hue-purity with the transitional intermediate color as a reference, the offset color of the hue is the main psychological primary color, and the impurity degree y % is half of the difference between the percentage proportions of the two psychological primary colors in the hue. For example, when red and yellow are detected in the color of the colored gemstone samples, if red is assumed as the main psychological primary color, yellow as the secondary psychological primary color, the hue-purity can be: hue-purity=x % yellow to red, wherein x % is the percentage proportion of yellow in the hue; the hue-purity can also be: hue-purity=y % red to orange, wherein y % is half of the difference between the percentage proportion of red and the percentage proportion of yellow in the hue. What is more appropriate is that, when green and blue or yellow and green are detected in the color of colored gemstone samples, the hue-purity can be better indicated as x % the secondary psychological primary color to the main psychological primary color.

[0061] In addition to the Natural Color System, we can also use the Ostwald Color System to determine the blackness and chromaticness of the color of the colored gemstone. In this system, color is also considered a constant, visually made up of white, black and pure chromatic color (it's called full color in the system), namely, value W (the amount of white in a color)+value B (the amount of black in a color)+value C (the amount of full color in a color)=100(%). Said value B and value C are respectively equivalent to the blackness and chromaticness in this application, and the hue is still determined by using the Natural Color System.

[0062] It should be noted that the method of testing the color quality of a colored gemstone provided in this application takes the color of the colored gemstone as a purely psychological sense and uses a psychology-based research method. Therefore, the components, parameters and color-strength of gem color involved in this application are psychological attributes and visual characteristics of color, and have nothing to do with the material components (physical or chemical components), spectral components or spectral parameters of color. For example, if a reconciled pigment including red and white is uniformly mixed with green pigment, then the physical concentration of the red pigment and the green pigment will be reduced, but the color strength of the new reconciled pigment on psychological feeling will be increased, this is because the mixing of red and green pigments will cause the change of the original colored component (namely, red), such as the creation of a new black component, which is a color component in color perception and not a black pigment in material.

[0063] In order to ensure the objectivity and fairness of the test results, it is necessary to use D50, D55 or D65 standard illumination environments while conducting the color quality tests, namely, the color temperature of the illumination is 4500K5500K (D50), 5000K6000K (D55) or 6000K7000K (D65), the color rendering index should be no less than 90, incidents from one side in the form of diffused light, and the illuminance formed in the observation plane should be within 1500 lx2500 lx. Samples to be tested are placed in an opaque and non-directional reflective white backing; the surrounding color of the test environment is a non-directional reflective neutral color (e.g. white) and is undisturbed by other light or color.

[0064] The application is further illustrated by the following specific implementation embodiments:

Example 1

[0065] Jadeite is a kind of gem with rich colors. The method provided in this application is used to establish a standard color library for jadeite for testing the color quality of jadeites.

[0066] 1) Collect a plurality of representative color samples of jadeite as the training set.

[0067] This implementation embodiment has collected 200 jadeite samples, the color of the samples covers green, white, yellow, red and purple, wherein green includes vivid yellowish green, vivid green, spicy green, apple green, spinach green, dark green and other common specific colors named by the market, and purple includes pinkish purple, reddish purple, bluish purple, strong purple, eggplant purple and other common specific colors.

[0068] 2) In a D50 standard illumination environment, use a NCS color scan to determine the blackness, chromaticness and hue of the color of the samples in the training set. The test results of all colors of samples are shown in Table 1 (due to the huge amount of data, Table 1 only lists the test results of some typical colors).

TABLE-US-00001 TABLE 1 Color Parameters NCS Blackness/ Chromaticness/ Sample No. Notation % % Hue Vivid S 5 72 Green 82%, Yellowish- 0572-G18 yellow 18% green Y Sample 1 Vivid S 6 75 Green 80%, Yellowish- 0675-G20 yellow 20% green Y Sample 2 Spicy S 3361-G 33 61 Pure green Green Sample 1 Spinach S 4251-G 42 51 Pure green Green Sample 1 Spinach S 51 43 Green 93%, Green 5143-B93 blue 7% Sample 2 G Apple S 1161-G 11 61 Pure green Green Sample 1 Dark Green S 85 6 Green 95%, Sample 1 8506-B95 blue 5% G Green S 56 36 Green 71%, Sample 1 5636-G29 yellow 29% Y White S 5 7 Blue 84%, red Sample 1 0507-R84 16% B White S 0505-G 5 5 Pure green Sample 2 Yellow S 2463-Y 24 63 Pure yellow Sample 1 Yellow S 33 60 Yellow 94%, Sample 2 3360-Y6R red 6% Red Sample S 35 58 Red 73%, 1 3558-Y73 yellow 27% R Purple S 31 32 Red 59%, blue Sample 1 3132-R41 41% B Purple S 53 30 Blue 62%, red Sample 2 5330-R62 38% B Purple S 22 30 Red 70%, blue Sample 3 2230-R30 30% B

[0069] 3) Calculate the hue-purity, color-strength and relative chromaticity of the color of the samples according to the blackness, chromaticness and hue. Wherein, hue-purity is x % the secondary psychological primary color to the main psychological primary color, wherein x % is the percentage proportion of the secondary psychological primary color in the hue; color-strength=blackness+chromaticness; relative chromaticity=chromaticness/color-strength. See the results in Table 2 (due to the huge amount of data, Table 2 only lists the calculation results of the quality indexes of the colors in Table 1).

TABLE-US-00002 TABLE 2 Compared to the typical quality characteristics Color Quality Indexes in people's Sample Color- Relative common sense No. Hue-purity strength/% chromaticity/% and experience Vivid 18% 77 93.5 Vivid Yellowish yellow yellowish green to green with Sample 1 Green moderate Vivid 20% 81 92.6 strength Yellowish yellow green to Sample 2 Green Spicy 100% 94 64.9 Pure green Green Green similar to Sample 1 pepper Spinach 100% 93 54.8 Dull green Green Green similar to Sample 1 spinach Spinach 7% blue 94 45.7 Green to Sample 2 Green Apple 100% 72 84.7 Light green Green Green similar to Sample 1 green apple Dark 5% blue 91 7.0 Dark green Green to similar to Sample 1 Green black Green 29% 92 39.1 Yellowish and Sample 1 yellow grayish green to Green White 16% red 12 58.3 Color is very Sample 1 to Blue light, little significance for the test of hue-purity and relative chromaticity White 100% 10 50 Color is very Sample 2 Green light, little significance for the test of hue-purity and relative chromaticity Yellow 100% 87 72.4 Khaki Sample 1 Yellow Yellow 6% red 93 64.5 Khaki with a Sample 2 Yellow little bit of orange Red 27% 93 62.4 Maroon Sample 1 yellow to Red Purple 41% 63 50.8 Purple with Sample 1 blue to moderate Red color-strength Purple 38% red 83 36.1 Bluish purple Sample 2 to Blue Purple 30% 52 57.7 Light pinkish Sample 3 blue to purple Red

[0070] In Table 2, we can also use the transitional intermediate color as a reference to calculate and indicate the hue-purity. The calculation method is: Hue-purity is y % the main psychological primary color to the transitional intermediate color, wherein y % is half of the difference between the percentage proportion of the main psychological primary color in the hue and the percentage proportion of the secondary psychological primary color in the hue. So the hue-purity of Yellow Sample 2, Red Sample 1, Purple Sample 1, Purple Sample 2, and Purple Sample 3 can be indicated in turn as: 44% yellow to Orange, 23% red to Orange, 9% red to Purple, 12% blue to Purple, and 20% red to Purple.

[0071] 4) After the analysis, statistics and calibration of the index parameters of all the colors in the training set, we then identify, classify, quantity and define the specific colors represented by the samples, according to the quantified hue-purity, color-strength and relative chromaticity. Each color is defined in Table 3 (due to the huge amount of data, Table 3 only lists definitions of some typical colors)

TABLE-US-00003 TABLE 3 Color-strength/% 90> 81> Color- Color- Color- strength 90 strength 81 strength 60 60> Color- Color- Color- (can be (can be (can be strength 40 strength <40 strength defined as defined as defined (can be (can be Hue\ extremely very as defined defined as purity strong) strong) strong) as weak) very weak) 10%~20% relative relative light (contains) chromaticity 60: chromaticity 60: green yellow yellowish green vivid yellowish to green Green 6> relative chromaticity <60: relative chromaticity >15: relative chromaticity 15: dark green 0 (contains)~10% relative relative relative (contains) chromaticity 60: chromaticity 60: chromaticity 60: yellow strong vivid green apple to green green Green 60> relative chromaticity 50: relative spicy green chromaticity <60: 50> relative chromaticity 15: spinach green relative relative chromaticity 15: chromaticity 15: dark green 0~20% relative chromaticity 50: (contains) bluish green blue to 5> relative chromaticity <50: Green relative chromaticity >15: relative chromaticity 15: dark green 10% (contains)~30% relative chromaticity 50: reddish purple relative blue to chromaticity 50: Red pinkish purple relative chromaticity <50: 30% (contains)~40% Bluish purple red to Blue 30% relative chromaticity 50: vivid purple light (contains) 50> relative chromaticity 30: eggplant purple blue to purple Red~30% relative chromaticity <30: red to Blue White Color-strength <15; the test of hue-purity and relative chromaticity may not be done

[0072] In Table 3, accurate quantitative definitions are given to the jadeite colors common to the market according to the hue-purity, color-strength and relative chromaticity. And the so-called strong degree of color-strength can match the moderate strength in people's common sense and experience in Table 2. Other undefined colors can be directly classified and named by hue according to the hue-purity, for example, the color whose hue-purity is 15% blue to green can be named as bluish green. As purple is one of the typical colors of jadeite, the colors that contain a blue component and a red component can also be named as purple, reddish purple, or bluish purple. When the color-strength is less than 15% (nearly pure white), all colors can be called white.

Example 2

[0073] Testing the color quality of unknown jadeites.

[0074] Step One: Use a NCS color scan to determine the blackness, chromaticness and hue of the color of jadeite samples to be tested in a D50 standard illumination environment. The test results are shown in Table 4.

TABLE-US-00004 TABLE 4 Sample NCS Color Parameters No. Notation Blackness/% Chromaticness/% Hue Unknown S 38 48 Green 89%, sample 1 3848-B89G blue 11% Unknown S 20 71 Green 81%, sample 2 2071-G19Y yellow 19% Unknown S 4133-G 41 33 Pure green sample 3 Unknown S 5 42 Green 83%, sample 4 0542-G17Y yellow 17% Unknown S 51 40 Green 90%, sample 5 5140-G10Y yellow 10% Unknown S 42 30 Blue 51%, sample 6 4230-R49B red 49% Unknown S 42 39 Yellow 87%, sample 7 4239-Y13R red 13%

[0075] Step Two: Calculate the hue-purity, color-strength and relative chromaticity of the color of the samples for testing the color quality of the samples. Identify, classify and name them according to the color definitions in Table 3 in Example 1. The test conclusions are shown in Table 5.

TABLE-US-00005 TABLE 5 Color Quality Indexes Sample Color- relative Test No. Hue-purity strength/% chromaticity/% Conclusion Unknown 11% blue 86 55.8 Bluish green sample 1 to Green Unknown 19% 91 78.0 Yellowish sample 2 yellow to green Green Unknown 100% 74 44.6 Spinach green sample 3 Green Unknown 17% 47 89.4 Vivid sample 4 yellow to yellowish Green green Unknown 10% 91 44.0 Spinach green sample 5 yellow to Green Unknown 49% red to 72 41.7 Purple sample 6 Blue or indicated as 1% blue to Purple Unknown 13% red to 81 48.1 Yellowish sample 7 Yellow orange or indicated as 34% yellow to Orange

Example 3

[0076] Use the method of testing the color quality of a colored gemstone provided in this application to identify the color quality of rubies suspected to be pigeon's blood.

[0077] Pigeon's blood is a red considered to have the best quality and highest value with regard to rubies. As the old saying goes, a little difference in color can lead to a big difference in price. Therefore, it is of great importance to use the method of testing the color quality of a colored gemstone provided in this application to identify pigeon's blood.

[0078] First, collect a plurality of market-recognized rubies with the color of pigeon's blood as the training set, use a NCS color scan to determine the blackness, chromaticness and hue of the samples in a D50 standard illumination environment, and calculate the hue-purity, color-strength and relative chromaticity of the pigeon's blood. After the systematic analysis, statistics and correction, the quantitative definition of the pigeon's blood according to the hue-purity, color-strength and relative chromaticity is obtained as shown in the following Table 6:

TABLE-US-00006 TABLE 6 Quality Typical Index Color- relative quality Color Hue-purity strength/% chromaticity/% characteristics Pigeon's 0 (contains)~ 90 85 Extremely blood 15% pure of the (contains) hue, yellow to extremely Red strong of the color-strength and the relative chromaticity.

[0079] Identity the colors suspected pigeon's blood. Calculate the quality indexes of the samples according to the color parameters determined by a NCS color scan in a D50 standard illumination environment, and match them with Table 6. The test conclusions are shown in Table 7.

TABLE-US-00007 TABLE 7 Color Quality Indexes Relative Sample Color- chromaticity/ Test No. Hue-purity strength/% % Conclusion Ruby 9% yellow 92 93.5 pigeon's blood sample 1 to Red Ruby 2% blue to 90 94.4 isn't pigeon's sample 2 Red blood Ruby 100% Red 88 93.2 isn't pigeon's sample 3 blood Ruby 16% yellow 93 89.2 isn't pigeon's sample 4 to Red blood Ruby 100% Red 91 87.9 pigeon's blood sample 5 Ruby 2% yellow 95 94.7 pigeon's blood sample 6 to Red

[0080] Match the index parameters in Table 7 with Table 6 and the following test conclusion can be obtained: In the six rubies, though sample 2, sample 3 and sample 4 are very similar to pigeon's blood in appearance, they cannot be identified as pigeon's blood as the hue-purity of sample 2 and sample 4 is not pure enough and the color-strength of sample 3 is not enough; Only sample 1, sample 5 and sample 6 can be truly identified as pigeon's blood, and the color quality of sample 1, sample 5 and sample 6 from high to low is sample 6 (relative chromaticity 94.7%), sample 1 (relative chromaticity 93.5%) and then sample 5 (relative chromaticity 87.9%).

[0081] The above are further explanations of this application on the basis of specific preferred implementation embodiments, it cannot be deemed that the specific implementation of this application is only limited to these explanations. For technical staff in the field to which this application belongs, with the premise of not departing from the idea of this application, they can make a number of equivalents or obvious variations with the same performance or use, all these should be regarded as within the protection scope of this application.

[0082] Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.