RGB to CMY and CMYK

• RGB to CMY (ideal case)

  • C = 255 - R
  • M = 255 - G
  • Y = 255 - B

• CMY to CMYK RGB to CMYK

  • K = min(C,M,Y) K = 255 - max(R, G, B)
  • C = 255 (C - K) / (255 - K) C = 255 (m - R) / m
  • M = 255 (M - K) / (255 - K) M = 255 (m - G) / m
  • Y = 255 (Y - K) / (255 - K) Y = 255 (m - B) / m
  • 2-D lookup tables m = max(R, G, B)

• R, G, B, C, M, Y, and K have a range of [0,255]

• Useful in printers and copiers

Division takes 1 or 2instructions per bitof precision in result

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