Expanded color space

1. A process for color printing an image with angled half tone screens and a colorant set that includes Cyan, Magenta, Yellow and Black colorants and at least one other colorant comprising:

choosing the at least one other colorant so that one of the at least one other colorant is a colorant having a hue angle intermediate the hue angles of Cyan and Magenta;

assigning a screen angle to each of the colorants in the colorant set:

providing an angled half tone screen for each of the colorants of the colorant set responsive to a color separation of the image; and

using the angled half tone screens to produce a color printing of the Image,

wherein the number of colorants in the colorant set is odd and assigning a screen angle to each of the colorants of the colorant set comprises assigning black a first screen angle, assigning one half of said non-black colorants a second screen angle and one half of said non-black colorants a third screen angle, wherein said first, second and third screen angles are different and wherein non-black colorants having adjacent hue angles are assigned different screen angles.

2. A process for color printing an image with angled half tone screens and a colorant set that includes Cyan, Magenta, Yellow and Black colorants and at least one other colorant comprising:

choosing the at least one other colorant so that one of the at least one other colorant is a colorant having a hue angle intermediate the hue angles of Cyan and Magenta;

assigning a screen angle to each of the colorants in the colorant set;

providing an angled half tone screen for each of the colorants of the colorant set responsive to a color separation of the image; and

using the angled halftone screens to produce a color printing of the image,

wherein the number of colorants in the colorant set is even and assigning a screen angle to each of the colorants of the colorant set comprises assigning black a first screen angle, assigning one half of said colorants that are neither black or yellow a second screen angle and one half of said colorants that are neither black or yellow a third screen angle, wherein yellow is assigned a fourth screen angle, wherein said first, second, third and fourth screen angles are different and wherein non-black colorants having adjacent hue angles are assigned different screen angles.

3. A process according to claim 1 wherein the angle between said first screen angle and either of said second and third screen angles is substantially 30° and the angle between said second and said third screen angles is substantially 30°.

4. A process according to claim 3 wherein said first screen angle is 45°, one of said second and third screen angles is 15° and the other of said second and third screen angles is 75°.

5. A process according to claim 2 wherein choosing the at least one other colorant comprises choosing two colorants.

6. A process according to claim 2 wherein the difference between said fourth screen angle and said first screen angle is 45°.

7. A process according to any of the previous claims wherein choosing the at least one other colorant so that one of the at least one other colorant is a colorant having a hue angle intermediate the hues angles of Cyan and Magenta comprises choosing a colorant substantially exterior to the gamut of hues provided by said Cyan, Magenta, Yellow and Black colorants.

8. A process according to any of claims 1 – 4 wherein choosing the at least one other colorant so that one of the at least one other colorant is a colorant having a hue angle intermediate the hue angles of Cyan and Magenta comprises choosing violet.

9. A process according to any of claims 1 – 4 wherein choosing the at least one other colorant comprises choosing at least two other colorants and wherein one of the at least two other colorants is Orange.

10. A process according to any of claims 1 – 4 wherein Cyan and Magenta have the same screen angles.

11. A color printing of an image produced using a process according to any of claims 1 – 4 .

12. A colorant set for color printing with angled half tone screens comprising:

at least five colorants including Cyan, Magenta, Yellow and Black colorants; and at least one colorant have a hue angle intermediate the hue angles of Cyan and Magenta,

wherein the number of the at least five colorants is odd wherein said black colorant has a first screen angle, wherein one half of said non-black colorants have a second screen angle and one half of said non-black colorants have a third screen angle, wherein said first, second and third screen angles are different and wherein non-black colorants having adjacent hue angles have different screen angles.

13. A colorant set for color printing with angled halftone screens comprising;

at least five colorants including Cyan, Magenta, Yellow and Black colorants; and at least one colorant have a hue angle intermediate the hue angles of Cyan and Magenta,

wherein the number of the at least five colorants is even, wherein said black colorant has a first screen angle, wherein one half of said colorants that are neither black or yellow have a second screen angle and one half of said colorants that are neither black or yellow have a third screen angle, wherein yellow has a fourth screen angle, wherein said first, second, third and fourth screen angles are different and wherein non-black colorants having adjacent hue angles have different screen angles.

14. A colorant set according to claim 12 wherein the angle between said first screen angle and either of said second and third screen angles is substantially 30° and the angle between said second and said third screen angles is substantially 30°.

15. A colorant according to claim 14 wherein said first screen angle is 45°, one of said second and third screen angles is 150 and the other said second and third screen angles is 75°.

16. A colorant set according to claim 13 wherein the number of the at least five colorants is six.

17. A colorant set according to claim 13 wherein the difference between said fourth screen angle and said first screen angle is 45°.

18. A colorant set according to any of claims 12 – 15 wherein the at least one colorant having a hue angle intermediate the hue angles of Cyan and Magenta is a colorant substantially exterior to the gamut of hues provided by said Cyan, Magenta, Yellow and Black colorants.

19. A colorant set according to any of claims 12 – 15 wherein said at least one colorant having a hue angle intermediate the hue angles of Cyan and Magenta comprises one colorant.

20. A colorant set according to any of claims 12 – 15 wherein at least one of said at least one colorant having a hue angle intermediate the hue angles of Cyan and Magenta is Violet.

21. A colorant set according to any of claims 12 – 15 wherein at least one of said at least one colorant having a hue angle intermediate the hue angles of Cyan and Magenta is Purple.

22. A colorant set according to any of claims 12 – 15 comprising at least 6 colorants wherein one of the colorants is Orange.

23. A colorant set according to any of claims 12 – 15 wherein Cyan and Magenta have the same screen angles.

24. A process for color printing an image with angled halftone screens and a colorant set that includes Cyan, Magenta, Yellow and Black colorants and at least one other colorant comprising:

choosing the at least one other colorant so that one of the at least one other colorant is a colorant having a hue angle intermediate the hue angles of Cyan and Magenta;

assigning a screen angle to each of the colorants in the colorant set;

providing an angled half tone screen for each of the colorants of the colorant set responsive to a color separation of the image; and

using the angled half tone screens to produce a color printing of the Image,

wherein choosing the at least one other colorant so that one of the at least one other colorant is a colorant having a hue angle intermediate the hues angles of Cyan and Magenta comprises choosing a colorant substantially exterior to the gamut of hues provided by said Cyan, Magenta, Yellow and Black colorants.

25. A process for color printing an image with angled half tone screens and a colorant set that includes Cyan, Magenta, Yellow and Black colorants and at least one other colorant comprising:

choosing the at least one other colorant so that one of the at least one other colorant is a colorant having a hue angle intermediate the hue angles of Cyan and Magenta;

assigning a screen angle to each of the colorants in the colorant set;

providing an angled half tone screen for each of the colorants of the colorant set responsive to a color separation of the image; and

using the angled halftone screens to produce a color printing of the image,

wherein choosing the at least one other colorant so that one of the at least one other colorant is a colorant having a hue angle intermediate the hue angles of Cyan and Magenta comprises choosing violet.

26. A colorant set for color printing with angled half tone screens comprising:

at least five colorants including Cyan, Magenta, Yellow and Black colorants; and

at least one colorant have a hue angle intermediate the hue angles of Cyan and Magenta,

wherein the at least one colorant having a hue angle intermediate the hue angles of Cyan and Magenta is a colorant substantially exterior to the gamut of hues provided by said Cyan, Magenta, Yellow and Black colorants.

27. A process for color printing an image with angled halftone screens and a colorant set that includes Cyan, Magenta, Yellow and Black colorants and at least one other colorant comprising:

choosing the at least one other colorant so that one of the at least one other colorant is a colorant having a hue angle intermediate the hue angles of Cyan and Magenta;

assigning a screen angle to each of the colorants in the colorant set;

providing an angled half tone screen for each of the colorants of the colorant set responsive to a color separation of the image; and

using the angled halftone screens to produce a color printing of the image,

wherein cyan and magenta have a same screen angle.