Spot Color Tint Rendering with L*a*b* to CMYK Conversion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for rendering spot colors in image forming devices often result in inconsistent hue representation across tint variations, particularly when using CMYK recipes, leading to discontinuities between emulated tints and true spot colors.
Innovation Solution
The system converts device colorant recipes, such as CMYK, to referencing component values in a color space like L*a*b*, allowing for accurate calculation of tints while avoiding discontinuities by calculating a target color based on the mixture percentage between a spot color and another color, and then determining a device colorant recipe to produce the target color.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If device independent L*a*b* target values are used to calculate tints, then color accuracy is improved, but discontinuities appear between tints and the true spot color
Solution Approach 1:
The patent introduces an intermediary approach by combining device-independent L*a*b* color space calculations with device-dependent CMYK recipe adjustments. The system uses L*a*b* for accurate color representation but incorporates a spot color emulation recipe as a mediator to ensure continuity between tints and the solid spot color, resolving the discontinuity issue while maintaining color accuracy.
Solution Approach 2:
The system dynamically adjusts CMYK colorant parameters based on the calculated L*a*b* target values. By modifying the CMYK recipe parameters in response to the L*a*b* color specifications, the system achieves both accurate color representation and smooth transitions across tint variations, eliminating the discontinuities that would otherwise appear.
2Device complexity
If predetermined CMYK recipes are used for spot color emulation, then device complexity is reduced, but hue consistency across tints deteriorates
Solution Approach 1:
The patent transitions from static predetermined CMYK recipes to a dynamic color rendering process. The system calculates appropriate CMYK values dynamically based on the desired tint percentage and the spot color emulation recipe, allowing the colorant mixture to adapt continuously across different tint levels while maintaining hue consistency and accuracy.
3Ease of operation
If simple linear interpolation of CMYK values is used, then ease of operation is improved, but manufacturing precision of color tints deteriorates
Solution Approach 1:
The patent replaces simple linear interpolation of CMYK values with a more sophisticated color space transformation approach. By converting to L*a*b* color space and back to CMYK, the system achieves perceptually uniform color transitions that are more accurate than linear interpolation, while still maintaining computational efficiency through the use of standard color transformation algorithms.
Data Source
AI summary
Systems and methods are provided for rendering tints of spot color objects or target colors between a spot color and a second color in image forming devices. In particular the systems and method provided allow for a sweep of a spot color to be rendered accurately, without discontinuities when transitioning from the tint to the solid spot color. The systems and method will prevent discontinuities even if the solid spot color has been modified by a user.