Accurate representation of interference colours (Michel-Lévy chart): from rendering to image colour correction

Area of Science:

• Geoscience
• Materials Science
• Microscopy Imaging

Background:

• Accurate digital representation of interference colors (Michel-Lévy chart) is essential for polarized light microscopy.
• Existing methods struggle with color accuracy due to variations in light sources and camera calibration.

Purpose of the Study:

• To develop and validate a workflow for accurate digital rendering of interference colors.
• To improve the fidelity of color correction profiles for polarized light microscopy images.

Main Methods:

• Developed a workflow incorporating light source color temperature and chromatic adaptation.
• Utilized color correction profiles tested against IT8.7/1 targets.
• Applied XYZ cLUT and Matrix only algorithms for camera calibration.
• Validated the workflow using a quartz wedge over a 80-2500 nm retardation range.

Main Results:

• The XYZ cLUT algorithm achieved ΔE₀₀ values as low as 1.1 at 100× magnification.
• Camera correction reduced mean ΔE₀₀ from 12.3 to 4.9 for sRGB images.
• Color differences were significantly reduced, approaching imperceptible levels (ΔE₀₀ < 1.0).

Conclusions:

• The presented workflow significantly enhances the accuracy of digital interference color representation in polarized light microscopy.
• Camera calibration using color targets is critical for reliable color reproduction.
• Further improvements may involve custom color targets for high-order interference colors.