SKIN COLOR MATCHING METHOD AND SYSTEM

• US 20090213379A1
• Filed: 03/02/2006
• Published: 08/27/2009
• Est. Priority Date: 03/02/2005
• Status: Active Grant

• Current Assignee: Charles Conrad Carroll, Trevor Coward
• Original Assignee: Charles Conrad Carroll, Trevor Coward
• Inventors: Carroll, Charles Conrad, Coward, Trevor
• Granted Patent: US 8,351,038 B2
• Time in Patent Office: Days
• US Class Current: 356/405
• CPC Class Codes: G01J 3/46 Measurement of colour; Colour measuring devices, e.g. colorimeters measuring colour temperature G01J5/60
• CPC Class Codes: G01J 3/462 Computing operations in or between colour spaces; Colour management systems
• CPC Class Codes: G01J 3/463 Colour matching
• CPC Class Codes: G01J 3/465 taking into account the colour perception of the eye; using tristimulus detection
• CPC Class Codes: G01N 21/25 Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands

Abstract

A first method for matching skin colors comprises measuring a spectral reflectance curve of an area of skin and determining a blend of pigments to match the skin'"'"'s color by combining spectral reflectance curves measured for pigments to produce a calculated spectral reflectance curve corresponding to that of the skin. The pigment blend is then used, for example, to pigment a medical prosthesis, so that it matches precisely its wearer'"'"'s skin. This method avoids the problem of metamerism in which colors that match under a first illumination no longer match under a second illumination. A second method uses a database of pigment blends generated by the first method. The color of an area of skin is measured and a pigment blend is selected from the database that provides a closest match. Apparatus for carrying out such color matching is also provided, together with palettes of suitable pigments for skin color matching.

Claims

1. A method of matching a skin color comprising the steps of providing color measuring means adapted to measure a first spectral reflectance curve of an area of skin to be matched, providing colorant database means containing a plurality of colorant spectral reflectance curves each for a respective one of a plurality of colorant means, measuring a first spectral reflectance curve for a selected area of skin, comparing said first spectral reflectance curve to said colorant spectral reflectance curves and determining a recommended blend of colorant means chosen from the colorant database means, said recommended blend having a calculated spectral reflectance curve substantially corresponding to the measured first spectral reflectance curve for the selected area of skin.

2. A method as claimed in claim 1, comprising the further steps of preparing a sample of said recommended blend in an application medium, measuring a spectral reflectance curve of the sample and comparing the curve of the sample and the first spectral reflectance curve for the selected area of skin in order to check the match.

3. A method as claimed in claim 1, comprising the additional step of recording in formulation database means a recommended blend of colorant means found to constitute a successful match, together with respective spectral reflectance curves and color values for the blend.

4. A method as claimed in claim 1, further comprising the step of providing a palette of colorant means corresponding to selected ones of the colorant means present in the colorant database means.

5. A method of matching a skin color comprising the steps of providing color measuring means adapted to measure color data of an area of skin to be matched, providing formulation database means containing a plurality of blends of colorant means that have previously been found to match skin colors by a method as claimed in claim 1, along with respective color data for said blends, measuring color data for a selected area of skin and selecting from the formulation database means a recommended blend of colorant means which has calculated color data closest to the color data measured for the selected area of skin.

6. A method as claimed in claim 5, wherein said color data comprise tristimulus color values, and the colorant blend selection step comprises calculating color differences between calculated color data for blends of colorant means and measured color data for the selected area of skin, according to at least one formula selected from a group comprising the Δ

E*, CMC and CIE94 formulae.

7. A method as claimed in claim 5, wherein said color data comprise spectral reflectance curves.

8. A method as claimed in claim 5, comprising the further steps of determining a difference between the color data calculated for the recommended blend of colorant means and the color data measured for the selected area of skin, comparing said difference with a predetermined threshold value, and when said difference exceeds the threshold value, modifying the recommended blend of colorant means to reduce said difference below the threshold value.

9. A method as claimed in claim 8, wherein said modification step comprises providing colorant database means comprising a plurality of colorant spectral reflectance curves each for a respective one of a plurality of colorant means and so modifying the recommended blend of colorant means using colorant means selected from the colorant database means that the modified recommended blend has a calculated spectral reflectance curve substantially corresponding to the first spectral reflectance curve measured for the selected area of skin.

10. A method as claimed in claim 5, also comprising the step of providing a palette of colorant means corresponding to colorant means used in the colorant blends present in the formulation database means.

13. Apparatus for matching skin color comprising color measurement means adapted to measure color data for a selected area of skin and operatively linked to first computing means, the first computing means being connected to formulation database means containing a plurality of blends of colorant means that have previously been found to match skin colors by a method as claimed in claim 1, along with respective color data of the blends, wherein the computing means is programmed to select from the formulation database means a recommended blend of colorant means which has calculated color data closest to the color data measured for the selected area of skin.

14. Apparatus as claimed in claim 13, wherein said color data comprise spectral reflectance curves.

15. Apparatus as claimed in claim 13, wherein said color data comprise tristimulus color values.

16. Apparatus as claimed in claim 13, also comprising a plurality of samples of colorant means corresponding to the colorant means present in the blends of colorant means present in the formulation database means

33. A prosthesis comprising material pigmented by a method as claimed in claim 1.

35. A skin condition camouflage composition comprising material pigmented by a method as claimed in claim 1.

37. A method as claimed in claim 6, wherein said tristimulus color values are expressed according to a system selected from a group comprising the CIE L*a*b* and CIE L*c*h°

systems.

11. Apparatus for matching skin color comprising color measurement means adapted to measure a first spectral reflectance curve for a selected area of skin and operatively linked to first computing means, the first computing means being connected to colorant database means containing a plurality of reference spectral reflectance curves each for a respective one of a plurality of colorant means, wherein the computing means is programmed to determine a recommended blend of colorant means by combining colorant reference spectral reflectance curves substantially to match a first spectral reflectance curve of the selected area of skin.

12. Apparatus as claimed in claim 11, also comprising a plurality of samples of colorant means corresponding to selected ones of those present in the colorant database means.

17. A palette of pigments for use in matching skin colors, comprising a white pigment, a first substantially yellow pigment, a first substantially red pigment, a cold-toned pigment and at least one balancing pigment.

18. A palette of pigments as claimed in claim 17, wherein said first substantially yellow pigment comprises a substantially mid-shade yellow pigment.

20. A palette of pigments as claimed in claim 18, wherein said substantially mid-shade yellow pigment is selected from a group comprising Pigment Yellow 93 (Color Index 20170), quinoline yellow (Color Index 47005), Pigment Yellow 1 (Color Index 11680), arylide yellow (Color Index 11710), Pigment Yellow 128 (Color Index 20037) and Pigment Yellow 180 (Color Index 21290).

21. A palette of pigments as claimed in claim 17, wherein the first substantially red pigment is a dark red pigment.

22. A palette of pigments as claimed in claim 17, wherein the first substantially red pigment is a blue-shade red pigment.

23. A palette of pigments as claimed in claim 17, wherein the first substantially red pigment is selected from a group comprising quinacridone magenta (Pigment Red 122;

Color Index

     73915), deep maroon (Pigment Red 63;

Color Index

     15880), perylene maroon (Pigment Red 179;

Color Index

     71130), D&

C Red 7 (Color Index 15850;

1), D&

C Red 33 (Color Index

     17200), and manganese violet (Color Index

     77742).

24. A palette of pigments as claimed in claim 17, wherein said cold-toned pigment comprises a green pigment.

25. A palette of pigments as claimed in claim 24, wherein said green pigment is selected from a group comprising chromium oxide green (Color Index 77288), viridian (hydrated chromium oxide green;

Color Index

     77289) and phthalocyanine green (Color Index

     74265).

26. A palette of pigments as claimed in claim 17, wherein said cold-toned pigment comprises a blue pigment.

27. A palette of pigments as claimed in claim 26, wherein said blue pigment is selected from a group comprising ultramarine blue (Color Index 77007), phthalocyanine blue (Color Index 74160) and Prussian blue (Color Index 77510).

28. A palette of pigments as claimed in claim 17, wherein said cold-toned pigment comprises a black pigment.

29. A palette of pigments as claimed in claim 17, wherein said cold-toned pigment comprises a violet pigment.

30. A palette of pigments as claimed in claim 17, wherein the balancing pigment comprises an iron oxide pigment selected from a group comprising Mars yellow (Color Index 77492), Mars red (Color Index 77491), maroon red (Color Index 77491), iron oxide oranges and browns (Color Index 77491 and 77492), iron oxide violet (Color Index 77105) and iron oxide black (Color Index 77499).

31. A palette of pigments as claimed in claim 17, wherein the balancing pigment comprises a dark red pigment selected from a group comprising perylene maroon (Color Index 71130) and D&

C Red 40 (Color Index

     16035).

32. A palette of pigments as claimed in claim 17, wherein the balancing pigment comprises an ultramarine pigment selected from a group comprising ultramarine pink and ultramarine blue (both Color Index 77007).

34. A prosthesis comprising material pigmented with a palette of pigments as claimed in claim 17.

36. A skin condition camouflage composition comprising material pigmented with a palette of pigments as claimed in claim 17.

19. (canceled)