Representing color gamuts in color charts

• US 7,643,036 B1
• Filed: 12/23/2002
• Issued: 01/05/2010
• Est. Priority Date: 12/23/2002
• Status: Active Grant

• Current Assignee: Adobe Inc.
• Original Assignee: Adobe Systems Incorporated (Adobe Inc.)
• Inventors: Rees, Clive M.
• Primary Examiner(s): Caschera; Antonio A
• Application Number:
  US10/327,744
• Time in Patent Office: 2,570 Days
• Field of Search: 345/590, 345/591, 345593-595, 345/597, 345/589, 345/601, 715/763, 715/810, 382/165
• US Class Current: 345/594
• CPC Class Codes: G01J 3/52 using colour charts
• CPC Class Codes: H04N 1/6058 Reduction of colour to a range of reproducible colours, e.g. to ink- reproducible colour gamut

Abstract

Methods and apparatus, including computer program products, for presenting color samples in a color chart. The color chart includes an arrangement of multiple color samples that include colored areas representing colors in a color space. Color samples in the arrangement are associated with one or more color identifiers that uniquely identify the colors represented by the corresponding color samples. A gamut identifier identifies a color gamut relative to the colors represented by the color samples in the arrangement. A gamut mapping is provided to map a color from outside the color gamut to a color inside the color gamut.

Claims

1. A system comprising:

a processor; and

a machine-readable storage device including instructions operable to cause the processor to provide a color chart for presenting color samples, the color chart comprising;

an arrangement of a plurality of color samples, each color sample representing a distinct color and having a colored area filled with a corresponding color in a color space;

one or more color identifiers associated with each color sample in the arrangement, the one or more color identifiers associated with each color sample having one or more values uniquely identifying the color represented by the corresponding color sample; and

a gamut identifier identifying a color gamut relative to the colors represented by the color samples in the arrangement where the identified color gamut defines a range of colors and respective color samples that cannot be reproduced by a first device and where the gamut identifier identifies a plurality of colors, represented by two or more color samples of the plurality of color samples in the arrangement, that are outside the identified color gamut.

2. The system of claim 1, wherein:

the arrangement is ordered according to one or more parameters of the color space.

3. The system of claim 1, wherein:

the gamut identifier identifies a color gamut of a printing device on a medium.

4. The system of claim 1, wherein:

the one or more color identifiers include hue values for the colors represented by the associated color samples.

5. The system of claim 4, wherein:

the one or more color identifiers include saturation values for the colors represented by the associated color samples.

6. The system of claim 5, wherein:

the one or more color identifiers include darkness values for the colors represented by the associated color samples.

7. The system of claim 6, wherein:

the hue, saturation and darkness values are each defined in the continuous range from 0 to 100.

8. The system of claim 1, wherein:

the gamut identifier includes a line representing saturation values as a function of hue values.

9. The system of claim 1, wherein:

each color sample occupies a location in the arrangement adjacent to one or more color samples representing colors having hue values substantially equal to the hue value of the color represented by the color sample.

10. The system of claim 9, wherein:

adjacent color samples representing colors that have substantially equal hue values form a sequence along which saturation values of represented colors vary monotonically from sample to sample.

11. The system of claim 1, wherein:

the color space is related to a device-independent color space.

12. The system of claim 11, wherein:

the device-independent color space is L*a*b* color space.

13. The system of claim 1, wherein:

the arrangement defines a two-dimensional array of color samples representing colors sharing a common darkness value.

14. The system of claim 13, wherein:

the array is a rectangular array.

15. The system of claim 13, wherein:

the arrangement includes a plurality of two-dimensional arrays, each array including only color samples representing colors sharing a darkness value that is different from the darkness value of colors represented by the color samples in every other array in the arrangement.

16. The system of claim 1, further comprising:

one or more additional gamut identifiers, each additional gamut identifier identifying a corresponding color gamut relative to the colors represented by the color samples in the arrangement.

17. The system of claim 1, further comprising:

a second gamut identifier identifying a color gamut relative to the colors represented by the color samples in the arrangement, where the second identified color gamut defines a range of colors and respective color samples that cannot be reproduced by a second device.

18. A computer-implemented method for representing colors in a color space, the method comprising:

arranging a plurality of color samples in a color chart, each color sample representing a distinct color and having a colored area filled with a corresponding color in the color space;

displaying one or more color identifiers with each color sample in the color chart, the one or more color identifiers associated with each color sample having one or more values uniquely identifying the color represented by the corresponding color sample; and

displaying, using a display device, a gamut identifier representing a color gamut relative to the colors represented by the color samples arranged in the color chart where the color gamut defines a range of colors and respective color samples that cannot be reproduced by a first device and where the gamut identifier identifies a plurality of colors, represented by two or more color samples of the plurality of color samples in the arrangement, that are outside the identified color gamut.

19. The method of claim 18, wherein:

displaying the gamut identifier includes representing a color gamut of a printing device on a medium.

20. The method of claim 18, further comprising:

mapping a first color from outside the color gamut to a second color inside the color gamut.

21. The method of claim 20, wherein:

mapping a first color includes mapping the first color that has a first saturation value to a second color that has a second saturation value that is smaller than the first saturation value.

22. The method of claim 20, wherein:

mapping a first color includes mapping the first color that has first a darkness value to a second color that has a second darkness value that is smaller than the first darkness value.

23. The method of claim 20, wherein:

mapping the first color includes mapping the first color to the second color such that a hue value of the first color is substantially equal to a hue value of the second color.

24. The method of claim 20, wherein:

mapping the first color includes mapping the first color to the second color such that a darkness value of the first color is substantially equal to a darkness value of the second color.

25. The method of claim 20, further comprising:

defining an outer region of the color gamut; and

wherein the second color is inside the outer region of the color gamut.

26. The method of claim 18, further comprising:

representing one or more additional color gamuts relative to the colors represented by the color samples arranged in the color chart.

27. The method of claim 18, further comprising:

using the color chart to;

identify a first color to be reproduced using the first device, where the first color is outside the range of colors that may be reproduced by the first device, and

compare the selected first color to a second color represented by a particular color sample within the range of colors that are reproducible by the first device; and

replacing the first color with the second color for reproduction using the first device.

28. The method of claim 18, further comprising:

replacing the gamut identifier with a second gamut identifier, the second gamut identifier identifying a color gamut relative to the colors represented by the color samples in the arrangement, where the second identified color gamut defines a range of colors and respective color samples that cannot be reproduced by a second device.

29. A machine-readable storage device tangibly embodying a computer program for representing colors in a color space, the computer program including instructions operable to cause a data processing apparatus to:

arrange a plurality of color samples in a color chart, each color sample representing a distinct color and having a colored area filled with a corresponding color in the color space;

display one or more color identifiers with each color sample in the color chart, the one or more color identifiers associated with each color sample having one or more values uniquely identifying the color represented by the corresponding color sample; and

display a gamut identifier representing a color gamut relative to the colors represented by the color samples arranged in the color chart where the color gamut defines a range of colors and respective color samples that cannot be reproduced by a first device and where the gamut identifier identifies a plurality of colors, represented by two or more color samples of the plurality of color samples in the arrangement, that are outside the identified color gamut.

30. The machine-readable storage device of claim 29, wherein the computer program including instructions operable to cause data processing apparatus to display the gamut identifier further includes instructions operable to cause data processing apparatus to:

represent a color gamut of a printing device on a medium.

31. The machine-readable storage device of claim 29, where the computer program further comprises instructions operable to cause data processing apparatus to:

map a first color from outside the color gamut to a second color inside the color gamut.

32. The machine-readable storage device of claim 31, wherein the computer program including instructions operable to cause data processing apparatus to map a first color further includes instructions operable to cause data processing apparatus to:

map the first color that has a first saturation value to a second color that has a second saturation value that is smaller than the first saturation value.

33. The machine-readable storage device of claim 31, wherein the computer program including instructions operable to cause data processing apparatus to map a first color further includes instructions operable to cause data processing apparatus to:

map the first color that has first a darkness value to a second color that has a second darkness value that is smaller than the first darkness value.

34. The machine-readable storage device of claim 31, wherein the computer program including instructions operable to cause data processing apparatus to map a first color further includes instructions operable to cause data processing apparatus to:

map the first color to the second color such that a hue value of the first color is substantially equal to a hue value of the second color.

35. The machine-readable storage device of claim 31, wherein the computer program including instructions operable to cause data processing apparatus to map a first color further includes instructions operable to cause data processing apparatus to:

map the first color to the second color such that a darkness value of the first color is substantially equal to a darkness value of the second color.

36. The machine-readable storage device of claim 31, where the computer program further comprises instructions operable to cause data processing apparatus to:

define an outer region of the color gamut; and

wherein instructions operable to cause data processing apparatus to map a first color include instructions operable to cause data processing apparatus to map a first color to a second color inside the outer region of the color gamut.

37. The machine-readable storage device of claim 29, where the computer program further comprises instructions operable to:

represent one or more additional color gamuts relative to the colors represented by the color samples arranged in the color chart.

38. A system comprising:

means for arranging a plurality of color samples in a color chart, each color sample representing a distinct color and having a colored area filled with a corresponding color in the color space;

means for displaying one or more color identifiers with each color sample in the color chart, the one or more color identifiers associated with each color sample having one or more values uniquely identifying the color represented by the corresponding color sample; and

means for displaying a gamut identifier representing a color gamut relative to the colors represented by the color samples arranged in the color chart where the color gamut defines a range of colors and respective color samples that cannot be reproduced by a first device and where the gamut identifier identifies a plurality of colors, represented by two or more color samples of the plurality of color samples in the arrangement, that are outside the identified color gamut.

39. The system of claim 38, wherein:

displaying the gamut identifier includes representing a color gamut of a printing device on a medium.

40. The system of claim 38, further comprising:

means for mapping a first color from outside the color gamut to a second color inside the color gamut.

41. The system of claim 40, wherein:

mapping a first color includes mapping the first color that has a first saturation value to a second color that has a second saturation value that is smaller than the first saturation value.

42. The system of claim 40 wherein:

mapping a first color includes mapping the first color that has first a darkness value to a second color that has a second darkness value that is smaller than the first darkness value.

43. The system of claim 40, wherein:

mapping the first color includes mapping the first color to the second color such that a hue value of the first color is substantially equal to a hue value of the second color.

44. The system of claim 40, wherein:

mapping the first color includes mapping the first color to the second color such that a darkness value of the first color is substantially equal to a darkness value of the second color.

45. The system of claim 40, further comprising:

means for defining an outer region of the color gamut; and

wherein the second color is inside the outer region of the color gamut.

46. The system of claim 38, further comprising:

means for representing one or more additional color gamuts relative to the colors represented by the color samples arranged in the color chart.

47. The system of claim 38, further comprising:

means for replacing the gamut identifier with a second gamut identifier, the second gamut identifier identifying a color gamut relative to the colors represented by the color samples in the arrangement, where the second identified color gamut defines a range of colors and respective color samples that cannot be reproduced by a second device.