RGB Colour
RGB Colour records the basic colour information of the surface image as three separate channels: red (R), green (G) and blue (B).
Parameter description
RGB Colour describes the appearance of the surface in terms of its digital image colour values rather than in a colour‑space such as CIELab. Each pixel in the observer‑camera image has an R‑G‑B triplet; the reported RGB Colour values are the average red, green and blue channel intensities over the analysed area, giving a simple numerical description of surface shade and tone.
How is it measured?
- The observer camera captures a colour‑corrected image of the surface using 45° circumferential illumination and 0° observation geometry.
- Software averages the red, green and blue pixel values within the defined measurement area (for example 18 Ă— 9 mm), reporting three numbers: R, G and B. These values can be trended, compared between batches or exported for further colour analysis.
Interpretation of values
- Higher R values indicate a stronger red component, higher G values a stronger green component, and higher B values a stronger blue component in the surface colour.
- Changes in RGB channel balance over time or between samples indicate colour drift, contamination, ageing or process variation, even when gloss and texture remain constant.
Applications
- Monitoring batch‑to‑batch colour consistency of coatings, plastics, inks and decorative films alongside gloss, haze and texture metrics.
- Quickly flagging visible colour shifts on production lines or during development trials without needing a dedicated spectrophotometer, and documenting the appearance of standards, master panels and reference parts in quality systems.
Technical Specification
| Item | Specification / Value |
|---|---|
| Index names | R, G, B |
| Description | Average red, green and blue channel intensities from the surface image |
| Units | 0–255 (8‑bit channel values) or normalised 0.0–1.0, depending on software configuration |
| Measurement geometry | 45° circumferential illumination, 0° observation (observer camera) |
| Field of view (FOV) | Dependent on module |
| Measurement principle | Capture of a colour image, followed by spatial averaging of R, G and B pixel values over the region |
| Measurement range | Full sensor range for each channel (typically 0–255) |
| Repeatability (typical) | Within ±1–2 channel |
| Reproducibility (typical) | Within ±3–5 channel counts after re‑positioning and re‑measurement |
| Primary use | Tracking colour/shade changes and documenting appearance alongside gloss, haze and texture parameters |