JP2007212140A - Prediction method of hair dyeing color - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a means capable of predicting simply and precisely a hair color after being dyed by mixed use of a plurality of hair dyeing agents. <P>SOLUTION: This prediction method of a hair dyeing color by mixed use of the plurality of hair dyeing agents includes (1) a process wherein hairs having a plurality of different color tones are dyed with one hair dyeing agent mixedly used with a fixed concentration, and each hair color before being dyed and after being dyed is used as color information of RGB system, and a relation expression of a color tone change between original hairs and dyed hairs relative to the hair dyeing agent is determined therefrom relative to R-value, G-value and B-value; (2) a process for determining the relation expression of the color tone change between the original hairs and the dyed hairs relative to another hair dyeing agent relative to the R-value, the G-value and the B-value; (3) a process for guiding a predicted pigment concentration expression of R-wavelength after mixed hair dyeing; (4) a process for guiding a predicted pigment concentration expression of G-wavelength and a predicted pigment concentration expression of B-wavelength after mixed hair dyeing; (5) a process for guiding a predicted R-value expression after mixed hair dyeing; (6) a process for guiding a predicted G-value expression and a predicted B-value expression after mixed hair dyeing; (7) a process for determining the predicted R-value, the predicted G-value and the predicted B-value; and (8) a process for displaying an anticipated hair dyeing color after mixed hair dyeing. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for predicting a hair color with a hair dye. More specifically, when a plurality of hair dyes are mixed and dyed, it is possible to easily predict the hair color after dyeing without actually using the hair dye. It relates to the prediction method.

  Conventionally, “fashion dyeing” and “hair coloring”, in which hair is dyed to a desired color using a hair coloring agent such as hair color or hair nail polish, have been widely used. The hair color after finishing with this hair dye is known to the user from the color sample after dyeing displayed on the packaging container of the hair dye, and the hair sample color after dyeing placed at the store. It was common to be. And the user also relied on these display contents and the like to determine the hair color after his own hair dyeing. However, the hair color after dyeing is not determined only by the color of the hair dye itself, but is also affected by the hair color before hair dyeing, so only the color sample of the hair dye is used. Based on this, there is a problem that it is difficult to determine the hair color after dyeing.

  In order to solve such a problem, the present applicant has already obtained the color information by measuring the color of the subject's hair, and this color information is obtained by previously coloring a plurality of hairs with a predetermined hair dye. By substituting into the relational expression of the change in color information before and after hair dyeing derived by measuring the color of the hair before and after hair dyeing, predicting the hair color information after dyeing the subject, A hair dyeing state prediction method for a hair dye characterized by displaying this is proposed (see Patent Document 1). According to this method, even if the subject does not actually use one type of hair dye, it is possible to easily predict the hair coloring state of the hair when the hair dye is used.

  On the other hand, if not only one type but also two or more types of hair dyes are mixed and used, depending on the combination and mixing ratio, extremely diverse hair colors can be obtained. It is very useful if the color of hair dyed by the mixed use of hair dyes can be predicted easily. However, in the above-described method, when a plurality of hair dyes are mixed and used, the hair color cannot be predicted without actually mixing them.

Japanese Patent Laid-Open No. 2004-144568

  Accordingly, there has been a demand for provision of means for easily and accurately predicting the hair color after hair dyeing by mixing and using a plurality of hair dyes.

  As a result of intensive studies to solve the above problems, the present inventors obtained a relational expression of color change before and after hair dyeing for each RGB value using the RGB color system for each hair dye to be mixed and used. The present invention finds that, by deriving an expression representing the pigment concentration in each wavelength region of RGB, it is possible to predict RGB values after hair dyeing by mixing and using a plurality of hair dyes at a predetermined ratio. It came to complete.

That is, the present invention
Next steps (1) to (8)
(1) Hair of a plurality of different color tones is dyed with a single hair dye that is mixed and used at a constant concentration, and the hair color before and after the hair coloring is used as RGB color information. A step of obtaining a relational expression of color change between the raw hair of the hair agent and the dyed hair with respect to the R value, the G value, and the B value;
(2) The process of (1) above is repeated for other hair dyes to be mixed and used, and the relational expression of the color tone change between the raw hair and the dyed hair of other hair dyes is determined for the R value, G value and B value. The required process
(3) The common logarithm of the value obtained by dividing 255 by the relational expression for the change in R tone for one hair dye used in combination, and 255 by the relational expression for the change in R tone for other hair dyes. Is obtained by multiplying the common logarithm of each hair dye by the mixing ratio of each hair dye, and adding the common logarithm multiplied by this mixing ratio to obtain the mixed hair dye. R after
Deriving a wavelength-predicted dye concentration formula (D _R ),
(4) Step (3) is repeated for the relational expression of the change in color tone of the G value and B value obtained in the above steps (1) and (2), and the predicted dye concentration formula for the G wavelength after mixed hair dyeing ( D _G ) and B wavelength prediction dye concentration formula (D _B )
(5) Divide 255 by the value raised to the power of 10 by the predicted dye concentration formula (D _R ) of R wavelength obtained in the above step (3) to derive the predicted R value formula (S _R ) after mixed hair dyeing Process,
(6) G wavelength predicted pigment concentration formula (D _G ) and B wavelength predicted pigment concentration formula (D _B ) determined in the above step (4), step (5) is repeated, and the predicted G after mixed hair dyeing Value expression (S
_G ) and deriving a predicted B-value equation (S _B ),
(7) The mixing ratio of each hair dye and the measured R value, measured G value and measured B value of the hair to be dyed,
Substituting into the predicted R value formula (S _R ), predicted G value formula (S _G ), and predicted B value formula (S _B ) obtained in the above steps (5) and (6), the predicted R value, predicted G value, and Obtaining a predicted B value;
(8) Dyeing by using a plurality of hair dyes, including the step of displaying the expected hair color after mixed hair coloring based on the predicted R value, predicted G value, and predicted B value obtained in step (7) above. This is a hair color prediction method.

  When the hair color prediction method of the present invention is used, in the case of hair dyeing using a mixture of a plurality of hair dyes, the hair color after hair dyeing can be used even if the subject does not actually use these hair dyes. Can be easily predicted.

  In addition, the present invention may be used as an index for accurately selecting a combination of hair dyes and a mixing ratio thereof necessary for dyeing a desired color without actually dyeing the subject's hair. It can be done.

  Therefore, the hair color prediction method of the present invention is advantageous in a store such as a cosmetic store or a beauty salon as a means for predicting the state of hair color obtained by mixing and using a plurality of hair dyes at a predetermined ratio. It can be used.

  The method for predicting a hair color by using a mixture of a plurality of hair dyes according to the present invention includes eight steps as described above. Hereinafter, each step will be described.

  First, in the step (1) of the present invention, a plurality of different color tones are dyed with a single hair dye that is mixed and used at a constant concentration, and the hair color before and after the dyeing is changed to an RGB color. This is a step of obtaining the relational expression of the color change between the raw hair and the dyed hair of the hair dye for the R value, G value, and B value.

  In order to obtain the relational expression of the color tone change, first, hair samples having different color tones are prepared, and each hair sample is hair before being dyed with one of a plurality of hair dyes to be mixed and used. It is necessary to obtain color information by measuring the hair color of the (primary hair) and the subsequent hair (dyed hair).

  The hair samples used for obtaining this color information are preferably collected for each range that can be considered to be the same kind to some extent within the range that can be judged from the appearance. For example, when targeting young general Japanese, it is preferable to collect hair that can be judged as black or dark brown in appearance as a hair sample. On the other hand, since the change after dyeing is different in hair that has been subjected to white hair, hair dyeing treatment or decoloring treatment, the hair color is preferably different from that of black or dark brown. .

  In addition, the ease with which a hair dye is dyed often varies depending on the thickness of the hair and the quality of the hair, such as whether it is straight hair, etc. It is preferable that color information is obtained by collecting items that can be regarded as the same type.

  By using 2 to 4 kinds, preferably 3 to 4 kinds of such hair samples, it is possible to obtain a relational expression for color tone change with sufficient accuracy.

  When dyeing hair samples, the concentration of the hair dye for each sample must be constant. Needless to say, it is preferable to carry out other dyeing conditions in common, and the conditions such as the amount of hair dye used and the hair dyeing time are also standard when using the hair dye used. Preferably.

  In order to obtain color information from the hair sample or the hair dyed thereto, according to a conventional method, for example, the hair sample is irradiated with white light, the reflected light is dispersed, the intensity of each wavelength is measured, and the information on each color is obtained. The hair color may be measured by a device using a method for obtaining a color, or a device using a method of irradiating spectral light and measuring reflected light intensity to obtain information on each color, for example, a portable spectrocolorimeter (CM- 503d: manufactured by Minolta Co., Ltd.) and the like, and the color information may be obtained by measuring the hair color. The display format of the color information in this hair color measurement is not limited to the RGB system, and any display system that can be finally converted to the RGB system is used. For example, a color system such as an XYZ system, a Lab system, or a CMYK system is used. be able to. In the case of such a color system other than the RGB system, it may be converted into RGB color information by a conventional method. For example, in the case of Lab system color information, it is defined by the CIE (International Lighting Commission). Conversion into RGB color information can be performed using a conversion formula.

  The number of gradations of the RGB color information obtained in this way uses 256 gradations so that the hair color can be appropriately expressed by the image display means or the like.

  Using the RGB color information of each hair sample obtained before and after dyeing with one of the hair dyes to be mixed and obtained as described above, an R value is obtained. For each of the G value and the B value, a relational expression of color tone change of the raw hair (hair sample before dyeing) and dyed hair (hair sample after dyeing) is obtained.

  The relational expression of the change in color tone is expressed as follows: for each sample, the R value, the G value, and the B value are expressed as x-axis (horizontal axis) for the raw hair and y-axis (vertical axis) for the dyed hair. The correlation equation can be obtained.

  More specifically, for each of the R value, the G value, and the B value, a point indicating the value of the raw hair and the value of the dyed hair is plotted on the xy coordinates for each sample. Since the plotted points are distributed along a certain straight line or curve, the expression indicating the straight line or curve can be used as a relational expression (correlation expression) of the color change between the raw hair and the dyed hair.

  In the step (2), the above step (1) is repeated for other hair dyes to be mixed and used, and the relational expression of the color change of the raw hair and the dyed hair of the other hair dye is expressed as R value, G value and This is a step for obtaining the B value. In this way, for all the hair dyes to be mixed and used, a relational expression for color change is obtained for each of the R value, the G value, and the B value.

In step (3), the relationship between the common logarithm of the value obtained by dividing 255 by the relational expression of the change in the color tone of the R value for one hair dye used in combination and the change in the color tone of the R value for the other hair dye Obtain the common logarithm of the value obtained by dividing 255 in the equation, multiply the common logarithm of each hair dye by the mixing ratio of each hair dye, and add the common logarithm multiplied by this mixing ratio. This is a step of deriving a predicted pigment concentration formula (D _R ) for the R wavelength after mixed hair dyeing.

と表すことができる。 The predicted dye concentration formula (D _R ) for the R wavelength is derived as follows. That is, since the color development of the hair dye is proportional to the amount of pigment in the hair, it can be predicted from the pigment concentration in the hair. In general, in object color measurement using diffused light, the following relationship is known for the dye density in an object. For a certain wavelength, if I ₀ is the light source intensity and I is the reflected light intensity, the density D is

It can be expressed as.

と表される。 In the above formula (1), since the I ₀ is the maximum value of 256 gradations (0 to 255), the prediction dye density _{D R} of the R value,

It is expressed.

  The relational expression of the change in color tone of the R value for one hair dye obtained in the step (1) represents the R value obtained by dyeing raw hair having a certain R value with the hair dye. If the relational expression is substituted for I in 2), the dye concentration at the R wavelength after hair dyeing with this hair dye is obtained. Thus, by calculating | requiring the common logarithm value of the value which divided 255 by the relational expression of the color tone change of R value about one hair dye used for mixing, in the R wavelength of the dyed hair which used the said hair dye The dye concentration can be obtained. Similarly, for each of the other hair dyes to be mixed and used, by obtaining the common logarithm value of the value obtained by dividing 255 by the relational expression of the color change of the R value obtained in the step (2), The dye density | concentration in R wavelength of the dyed hair which used the hair dye independently is calculated | required.

として導くことができる。 By multiplying the logarithmic value (R wavelength dye concentration) for each hair dye thus obtained by the mixing ratio of each hair dye and adding them together, a plurality of hair dyes are mixed and used. The dye concentration at the R wavelength of the dyed hair can be determined. For example, when two types of hair dye 1 and hair dye 2 are mixed and used at a ratio of x: y, the dye concentration at the R wavelength of the dyed hair by using each hair dye alone is D _r1 and D _r2. , dye density D _R of the R wavelength of Senshokuke after mixing the hair dye is

Can be guided as.

として導くことができる。 Similarly, it is possible to determine the R wavelength dye concentration of the dyed hair after mixed dyeing with three or more hair dyes. For example, when three types of hair dyes 1 to 3 are mixed and dyed at x: y: z, the dye concentration at the R wavelength of the dyed hair by using each hair dye alone is set to D _r1 , D _r2 , D _r3. When the dye concentration D _R in the R wavelength of Senshokuke after mixing the hair dye is

Can be guided as.

Step (4) repeats step (3) for the relational expression of the change in color tone of the G value and B value obtained in the above steps (1) and (2), and the predicted dye concentration formula for the G wavelength after mixed hair dyeing This is a step of deriving a predicted dye concentration formula (D _B ) for (D _G ) and B wavelength. In this way, the predicted pigment concentration formula after mixed hair dyeing is obtained for each wavelength of RGB.

Step (5) is a predicted R value formula (S _R ) after hair dyeing by dividing 255 by the value obtained by raising 10 to the power of the predicted dye concentration formula (D _R ) of R wavelength obtained in the above step (3). This is the process of guiding

となる。これより、

となり、２種類の染毛剤の混合染毛による予測Ｒ値式が得られる。 From the predicted dye concentration formula (D _R ) of the R wavelength after mixed hair dyeing with the plurality of hair dyes obtained in the step (3), a predicted R value formula after mixed hair dyeing can be obtained. That is, when the predicted R value is S _R , when two types of hair dyes are used in combination, from the above formulas (2) and (3)

It becomes. Than this,

Thus, a predicted R-value equation by mixed hair dyeing of two kinds of hair dyes is obtained.

となる。これより、

として、３種類の染毛剤の混合染毛による予測Ｒ値式が得られる。このように、１０をＲ波長の予測色素濃度式（Ｄ_Ｒ）によりべき乗した値で２５５を割ることによって、複数の染毛剤の混合染毛による予測Ｒ値式が導出される。 Similarly, it is possible to obtain a predicted R value formula by mixing and using three or more hair dyes. That is, in the case of three types, from the above formulas (2) and (4)

It becomes. Than this,

As a result, a predicted R-value formula by mixed hair dyeing of three kinds of hair dyes is obtained. Thus, by dividing 255 by the value obtained by raising 10 to the power of the predicted dye concentration formula (D _R ) for the R wavelength, a predicted R value formula for mixed hair of a plurality of hair dyes is derived.

The step (6) repeats the step (5) for the predicted pigment concentration formula (D _G ) for the G wavelength and the predicted pigment concentration formula (D _B ) for the B wavelength obtained in the above step (4), and after mixed hair dyeing This is a step of deriving a predicted G value formula (S _G ) and a predicted B value formula (S _B ). In this way, prediction formulas after mixed hair dyeing are derived for all of the R value, the G value, and the B value.

In the step (7), the mixing ratio of each hair dye and the actual R value, the actual G value, and the actual B value of the hair to be dyed are calculated as predicted R value formulas obtained in the above steps (5) and (6) ( S _R ), a predicted G value formula (S _G ), and a predicted B value formula (S _B ) are substituted into the predicted R value, predicted G value, and predicted B value. In this step, the predicted value of the RGB value of the hair color after the subject mixes a plurality of hair dyes at a predetermined ratio and dyes hair can be obtained as follows.

  First, the hair color of the hair to be dyed is measured. This measurement can be performed using various color systems in addition to the RGB system in the same manner as the acquisition of the color information of the hair sample described above.

  The color information obtained by the measurement of the hair color is converted to the RGB system in the case of color information based on a color system other than the RGB system, and is expressed as RGB 256 gradation color values. The measured R value, measured G value and measured B value of this hair to be dyed, and the mixing ratio of each hair dye, the predicted R value formula, predicted G value formula obtained in the above steps (5) and (6), By substituting into the predicted B value formula, a calculated value as a predicted value of the RGB value of the hair after mixed hair dyeing is obtained.

  Step (8) is a step of displaying the expected hair color after mixed hair dyeing based on the predicted R value, predicted G value, and predicted B value obtained in the above step (7). In this step, the color displayed by the predicted R value, predicted G value, and predicted B value obtained in step (7) dyes the subject's hair by mixing and using a plurality of hair dyes at a predetermined ratio. It becomes the expected dyed hair color.

  In addition, the expected hair color can be displayed in color by using various image display means, for example, an image display means such as a color liquid crystal or a color monitor. It is possible to predict the finished state due to the mixed use.

  EXAMPLES Next, although an Example is given and this invention is demonstrated in more detail, this invention is not restrict | limited at all by these Examples.

Example 1
The hair color was predicted by using two types of hair dyes mixed.
(Acquisition of color information)
Three types of hair bundles with the following specifications were measured using the SCE mode (regular reflection light removal) of a portable spectrocolorimeter (CM-503d: manufactured by Minolta) to measure the L * a * b * values before the hair was dyed. The color information of the bundle (raw hair) was acquired.

(Hair bundle specifications)
Color: Black, 2 types of tea, 4 types of white total Thickness: About 0.5-1μm
Length: about 15cm
Hair quality etc.: Straight hair

  Next, Cholestone Perfect 8/44 (color: purple: manufactured by Wella Japan Co., Ltd .; hereinafter sometimes abbreviated as “8/44”) as the hair dye, Welloxone Perfect 6% (Wella Japan) as the oxidant After dyeing with the following dyeing conditions, the L * a * b * values were measured in the same manner as before dyeing to obtain color information of the hair bundle (dyed hair) after dyeing. . The color information was confirmed with n = 6.

(Staining conditions)
1 g of the hair bundle was mixed with 2 g of the hair dye 2 g and the oxidizing agent, and then applied to the hair bundle and left at room temperature (about 25 ° C.) for 40 minutes. Thereafter, it was washed for about 1 minute in running water using a shampoo to obtain a dyed hair.

  The obtained color information data of the raw hair and the dyed hair is converted into RGB 256 gradation color values using a conversion formula defined by the CIE (International Lighting Commission), and the converted values of the color information of the raw hair and the dyed hair are respectively obtained. The relationship between color information was obtained by plotting on the horizontal and vertical axes. The result regarding the R value, G value, and B value of Cholestone Perfect 8/44 is shown in FIGS. From these results, the following formulas (9) to (11) were derived as approximate formulas showing the relationship between the raw hair and the dyed hair.

R ₄₄ = 0.5996R + 6.2874 (9)
G ₄₄ = 0.1799G + 7.0046 (10)
B ₄₄ = 0.098B + 17.525 (11)

In the above formulas, R, G, and B represent the RGB values of the raw hair, and R ₄₄ , G ₄₄ , and B ₄₄ represent the RGB values of the dyed hair that has been dyed using Cholestone Perfect 8/44.

  Next, as another hair dye, Cholestone Perfect 8/00 (color: Ash system: manufactured by Wella Japan Co., Ltd .; hereinafter, may be abbreviated as “8/00”) is used. Similarly, RGB256 gradation color values of the obtained raw hair and dyed hair were plotted. The results are shown in FIGS. Further, from the following, the following formulas (12) to (14) were obtained as approximate formulas showing the relationship between the raw hair and the dyed hair.

R ₀₀ = 0.2787R-3.798 (12)
G ₀₀ = 0.1654G + 9.3136 (13)
B ₀₀ = 0.1835B + 17.16 (14)

In the above formula, R, G, and B represent the RGB values of the raw hair, and R ₀₀ , G ₀₀ , and B ₀₀ represent the RGB values of the dyed hair dyed using Cholestone Perfect 8/00.

となる。 (Derivation of predicted pigment concentration formula after mixed hair dyeing)
Assuming that the predicted dye concentration of the R wavelength after mixed hair dye is D _R , from equations (3), (9), and (12)

It becomes.

となる。 Similarly, the predicted concentration of dye G wavelength _D G, the predicted concentration of dye B Wavelength When _{D B} Equation (3), (10) - (11), from (13) to (14),

It becomes.

となり、コレストン パーフェクト８／４４および８／００をｘ：ｙの割合で混合使用した場合の染毛後の予測Ｒ値式を得ることができる。 (Derivation of predicted R value formula, predicted G value formula and predicted B value formula after mixed hair dyeing)
When the predicted R value after mixed hair dyeing with a plurality of hair dyes is S _R , from Equations (6) and (15),

Thus, it is possible to obtain a predicted R value formula after hair dyeing when Cholestone Perfect 8/44 and 8/00 are mixed and used in a ratio of x: y.

となり、予測Ｇ値式および予測Ｂ値式が導かれる。 Similarly, assuming that the predicted G value and the predicted B value after mixed hair dyeing are S _G and S _B , from equations (6) and (16) to (17)

Thus, a predicted G value formula and a predicted B value formula are derived.

(Comparison between predicted RGB value after mixed hair dyeing and measured RGB value)
The mixing ratio of Choleston Perfect 8/44 and 8/00 is 8/44: 8/00 = 1: 3, 8/44: 8/00 = 1: 1, 8/44: 8/00 = 3: 1 The respective mixing ratios and the measured RGB values of the hair bundle (primary hair) before dyeing are used as the predicted R value formula, the predicted G value formula and the predicted B value formula (formula (18)) after the mixed dyeing obtained above. (20)), the predicted R value, predicted G value, and predicted B value were determined. Further, this hair bundle was mixed at the above mixing ratio, and was actually dyed under the above-mentioned dyeing conditions, and then the color information obtained by the above color information obtaining method was converted to obtain the measured RGB values of the dyed hair. . The measured RGB values of the raw hair, the predicted RGB values of the dyed hair, and the measured RGB values are shown in the table below.

  From this result, it is clear that the predicted value of the dyed hair after mixed hair dyeing with a plurality of hair dyes obtained by the method of the present invention and the actually measured value of hair actually mixed and dyed are highly correlated. became.

Example 2
The hair color was predicted by using a mixture of three kinds of hair dyes.
(Acquisition of color information)
Using the SCE mode (regular reflection light removal) of three types of hair bundles with the following specifications using a portable spectrocolorimeter (CM-503d: manufactured by Minolta), the L * a * b * values were measured ( Color information of raw hair) was obtained.

(Hair bundle specifications)
Color: Black, 2 types of tea, 4 types of white total Thickness: About 0.5-1μm
Length: about 15cm
Hair quality etc.: Straight hair

  Next, Cholestone Perfect 8/6 (color: purple: manufactured by Wella Japan Co., Ltd .; hereinafter may be abbreviated as “8/6”) as a hair dye, Welloxone Perfect 6% (Wella Japan ( After the hair dyeing under the following dyeing conditions, the L * a * b * value was measured in the same manner as before the hair dyeing to obtain color information after the hair dyeing (dyed hair). The color information was confirmed with n = 6.

(Staining conditions)
After 1 g of the hair bundle was mixed with 2 g of the dye 2 g and the oxidizing agent, it was applied to the hair bundle and allowed to stand at room temperature (about 25 ° C.) for 40 minutes. Thereafter, it was washed for about 1 minute in running water using a shampoo to obtain a dyed hair.

  The obtained color information data of the raw hair and the dyed hair is converted into RGB 256 gradation color values using a conversion formula defined by the CIE (International Lighting Commission), and the converted values of the color information of the raw hair and the dyed hair are respectively obtained. The relationship between color information was obtained by plotting on the horizontal and vertical axes. The results regarding the R value, G value and B value of Cholestone Perfect 8/6 are shown in FIGS. Further, from these results, the following formulas (21) to (23) were derived as approximate formulas showing the relationship between the color tone changes of the raw hair and the dyed hair.

R ₆ = 0.4206R + 8.88837 (21)
G ₆ = 0.2216G + 17.439 (22)
B ₆ = 0.3086B + 20.321 (23)

In the above formulas, R, G, and B represent the RGB values of the hair before dyeing, and R ₆ , G ₆ , and B ₆ represent the RGB values of the hair dyed using Cholestone Perfect 8/6.

  Next, as other hair dyes, Cholestone Perfect 8/11 (color: ash system; hereinafter sometimes abbreviated as “8/11”) and 8/33 (color: brown system; hereinafter “8/33”) (Both of which are manufactured by Wella Japan Co., Ltd.), and RGB256 gradation color values of raw hair and dyed hair obtained for each hair dye in the same manner as in the above-mentioned Cholestone Perfect 8/6. Were plotted to obtain the relationship of color information. The results for Cholestone Perfect 8/11 are shown in FIGS. 10-12, and the results for 8/33 are shown in FIGS. Also, from these, the following formulas (24) to (29) were derived as approximate formulas showing the relationship between the color tone changes of the raw hair and the dyed hair.

R ₁₁ = 0.4999R + 10.032 (24)
G ₁₁ = 0.5737G + 9.8594 (25)
B ₁₁ = 0.7122B + 6.0347 (26)
R ₃₃ = 0.5340R + 2.1814 (27)
_{G 33 = 0.3972G + 5.1177 (28} )
B ₃₃ = 0.2813B + 15.813 (29)

In the above formula, R, G, and B are the RGB values of the hair before dyeing, R ₁₁ , G ₁₁ , and B ₁₁ are Cholestone Perfect 8/11, and R ₃₃ , G ₃₃ , and B ₃₃ are Cholestone Perfect 8/33 The RGB value of the hair dyed using is shown.

となり、Ｒ波長の予測色素濃度式が得られる。 (Derivation of predicted pigment concentration formula after mixed hair dyeing)
When the concentration of the dye R wavelength after mixing the hair dye and _{D R,} equation (4) and (21), (24) and (27),

Thus, a predicted dye concentration formula for the R wavelength is obtained.

となり、Ｇ波長およびＢ波長の予測色素濃度式が得られる。 Similarly, the dye concentration _D G of the G wavelength after mixing the hair dye, the dye concentration of the B wavelength When _{D B,} Equation (4), (22) - (23), (25) - (26), ( From 28) to (29)

Thus, the predicted dye concentration formulas for the G wavelength and the B wavelength are obtained.

となりコレストン パーフェクト８／６、８／１１および８／３３をｘ：ｙ：ｚの割合で混合染毛した染色毛の予測Ｒ値式を得ることができる。 (Derivation of predicted R value formula, predicted G value formula and predicted B value formula after mixed hair dyeing)
When the predicted R value after mixed hair dyeing with a plurality of hair dyes is S _R , from Equations (8) and (30),

Next, it is possible to obtain a predicted R value formula for a dyed hair obtained by mixing and dyeing Cholestone Perfect 8/6, 8/11 and 8/33 at a ratio of x: y: z.

となり、予測Ｇ値式および予測Ｂ値式を得ることができる。

Similarly, assuming that the predicted G value and the predicted B value after mixed hair dyeing are S _G and S _B , from Equations (8), (31), and (32)

Thus, the predicted G value formula and the predicted B value formula can be obtained.

(Predicted RGB value after mixed hair dyeing)
Cholestone Perfect 8/6, 8/11 and 8/33, the mixing ratio of the three types of hair dyes was 8/6: 8/11: 8/33 = 1: 1: 1, 8/6: 8/11: 8/33 = 2: 1: 1, 8/6: 8/11: 8/33 = 1: 2: 1, 8/6: 8/11: 8/33 = 1: 1: 2 The ratio and the measured RGB value of the hair bundle (primary hair) before dyeing are used as the predicted R value formula, the predicted G value formula, and the predicted B value formula (formulas (33) to (35) after the mixed dyeing obtained above. )), And the predicted RGB value of the dyed hair was obtained. The measured RGB values of the raw hair and the predicted RGB values of the dyed hair are shown in Table 2 below.

  The hair color prediction method of the present invention can easily predict the hair color when a user uses a plurality of hair dyes at a predetermined ratio without actually using the hair dye. It is.

  Therefore, the method of the present invention can be used as an index for accurately selecting a combination of hair dyes and a mixing ratio thereof necessary for the user to dye hair to a desired color, such as a cosmetic store. It is useful at the store and beauty salon.

4 is a graph showing the relationship between R values of 8/44 primary hair and dyed hair in Example 1. FIG. 4 is a graph showing the relationship between G values of 8/44 primary hair and dyed hair in Example 1. FIG. 4 is a graph showing the relationship between the B values of 8/44 primary hair and dyed hair in Example 1. FIG. 3 is a graph showing the relationship between R values of 8/00 raw hair and dyed hair in Example 1. FIG. 2 is a graph showing the relationship between G values of 8/00 raw hair and dyed hair in Example 1. FIG. 2 is a graph showing a relationship between B values of 8/00 raw hair and dyed hair in Example 1. FIG. 4 is a graph showing the relationship between R values of 8/6 raw hair and dyed hair in Example 2. FIG. 4 is a graph showing the relationship between G values of 8/6 raw hair and dyed hair in Example 2. FIG. 4 is a graph showing a relationship between B values of 8/6 raw hair and dyed hair in Example 2. FIG. 6 is a graph showing a relationship between R values of 8/11 raw hair and dyed hair in Example 2. 6 is a graph showing the relationship between G values of 8/11 primary hair and dyed hair in Example 2. 6 is a graph showing the relationship between the B values of 8/11 raw hair and dyed hair in Example 2. 3 is a graph showing the relationship between R values of 8/33 raw hair and dyed hair in Example 2. 3 is a graph showing the relationship between G values of 8/33 raw hair and dyed hair in Example 2. 6 is a graph showing the relationship between B values of 8/33 primary hair and dyed hair in Example 2. more than

Claims (5)

Next steps (1) to (8)
(1) Hair of a plurality of different color tones is dyed with a single hair dye that is mixed and used at a constant concentration, and the hair color before and after the hair coloring is used as RGB color information. A step of obtaining a relational expression of color change between the raw hair of the hair agent and the dyed hair with respect to the R value, the G value, and the B value;
(2) The process of (1) above is repeated for other hair dyes to be mixed and used, and the relational expression of the color tone change between the raw hair and the dyed hair of other hair dyes is determined for the R value, G value and B value. The required process
(3) The common logarithm of the value obtained by dividing 255 by the relational expression for the change in R tone for one hair dye used in combination, and 255 by the relational expression for the change in R tone for other hair dyes. Is obtained by multiplying the common logarithm of each hair dye by the mixing ratio of each hair dye, and adding the common logarithm multiplied by this mixing ratio to obtain the mixed hair dye. R after
Deriving a wavelength-predicted dye concentration formula (D _R ),
(4) Step (3) is repeated for the relational expression of the change in color tone of the G value and B value obtained in the above steps (1) and (2), and the predicted dye concentration formula for the G wavelength after mixed hair dyeing ( D _G ) and B wavelength prediction dye concentration formula (D _B )
(5) Divide 255 by the value raised to the power of 10 by the predicted dye concentration formula (D _R ) of R wavelength obtained in the above step (3) to derive the predicted R value formula (S _R ) after mixed hair dyeing Process,
(6) G wavelength predicted pigment concentration formula (D _G ) and B wavelength predicted pigment concentration formula (D _B ) determined in the above step (4), step (5) is repeated, and the predicted G after mixed hair dyeing Value expression (S
_G ) and deriving a predicted B-value equation (S _B ),
(7) The mixing ratio of each hair dye and the measured R value, measured G value and measured B value of the hair to be dyed,
Substituting into the predicted R value formula (S _R ), predicted G value formula (S _G ), and predicted B value formula (S _B ) obtained in the above steps (5) and (6), the predicted R value, predicted G value, and Obtaining a predicted B value;
(8) Dyeing by using a plurality of hair dyes, including the step of displaying the expected hair color after mixed hair coloring based on the predicted R value, predicted G value, and predicted B value obtained in step (7) above. How to predict hair color.   The method for predicting a hair color according to claim 1, wherein the other hair dye is one kind.   The method for predicting a hair color according to claim 1, wherein there are two or more other hair dyes.   The method for predicting a hair color according to any one of claims 1 to 3, wherein 2 to 4 types of hair are used as the plurality of hairs having different color tones. The method for predicting a hair color according to any one of claims 1 to 4, wherein the predicted hair color is displayed by an image display method.

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