Laser Diffraction Gratings and Structural Color
Closely spaced directional structures can diffract light, producing an appearance that changes with illumination and viewing direction.
Direction matters
Rotating a grating changes the direction in which diffracted light is sent. That is why scan angle is recorded as part of each measured fauxlographic swatch.
Spacing matters
The effective structure depends on scan interval and on the marks produced by the selected laser parameters. Requested spacing is not the same as a guaranteed physical groove profile.
Measurement matters
A camera records one lighting and viewing arrangement. Treat sampled RGB values as a lookup for that setup, not a universal material color specification.