Interpreting Results- Effect Pigment Module
How Does Aesthetix Measure Sparkle and Graininess?
The Aesthetix measures sparkle and graininess using advanced imaging techniques that capture surface reflectance under specific lighting conditions.
Sparkle Measurement: Sparkle is quantified by identifying and analyzing bright points of light (sparkle points) that are significantly brighter than their surroundings under directional illumination. The system captures high-dynamic-range images using multiple light sources at 45° and a single image at 10° angles. The visibility, density, and size of these sparkle points are calculated based on contrast thresholds, luminance, and spatial distribution.
Graininess Measurement: Graininess is assessed under diffuse lighting conditions. The software analyzes the spatial variation in the luminance factor of the surface, focusing on intermediate spatial frequencies. This captures the non-uniform, granular texture perceived as graininess.
Measurements Provided by Aesthetix for Sparkle and Graininess
Sparkle Metrics:
Sparkle Density: Number of visible sparkle points per 100 mm².
Sparkle Visibility: Average intensity of visible sparkle points relative to the background.
Sparkle Area: Average size of individual sparkle points in square micrometers.
Graininess Metrics:
Graininess Value (G): Quantifies the perceived coarseness of a surface under diffuse lighting, adjusted for luminance levels.
Comparison and Application:
Use Sparkle Density and Visibility for applications where the brightness and concentration of sparkle points are critical (e.g., automotive coatings or cosmetics).
Use Graininess Value for assessing surface uniformity in diffuse lighting, especially in applications like interior finishes or textured coatings.
For most applications, both metrics provide complementary insights into surface appearance. Choose based on whether directional (sparkle) or diffuse (graininess) lighting conditions dominate in the product's end-use environment.
Visualizing Sparkle and Graininess Using Appearance Elements
The Rhopoint Appearance Elements software allows detailed visualization of sparkle and graininess:
Sparkle Visualization:
Open the "Sparkle View" tab to see a high-resolution image of sparkle points.
Adjust thresholds to highlight visible sparkle elements.
Use color-coded overlays to differentiate between sparkle density and visibility.
Graininess Visualization:
Switch to the "Graininess Map" view to see a luminance variation map.
Analyze spatial frequency data to understand the granularity distribution.
Interactive Tools:
Use zoom and pan tools to inspect specific regions.
Compare multiple samples side-by-side to evaluate consistency.
Adjusting Sparkle and Graininess
To modify sparkle or graininess:
For Sparkle:
Increase pigment size or concentration in coatings to enhance sparkle density.
Optimize application methods (e.g., spray angle or curing conditions) to improve uniformity.
Use directional additives or effect pigments for more pronounced sparkle effects.
For Graininess:
Adjust pigment dispersion or particle size during formulation to reduce graininess.
Ensure even application thickness to minimize texture inconsistencies.
Use finer polishing techniques or smoother substrates for a more uniform appearance.
By leveraging Aesthetix measurements, manufacturers can fine-tune processes to achieve desired visual effects while maintaining consistency across production batches.