Computational analysis of the photograph of the artwork Bb minor - Research on Harmony (AQC0612) [1] by Arnaud Quercy [2], according to IDS-CMP-2025 [3], on an image 1000 pixels on its longer side, on 2025-10-03. Each colour is located in the Munsell system and named according to the ISCC-NBS system (267 names, National Bureau of Standards, 1976). The image divides into 7 flat areas. The largest are moderate violet (53%), very dark red (31%) and moderate greenish blue (12%). Among the others, those that stand out most sharply from their surroundings are light grayish purplish red on the left (1.4%), grayish purplish pink in the centre (0.5%) and very dark reddish purple at the top right (0.8%). By colour name family: violet 52%, red 27%, blue 12%, brown 5.0%, purple 1.8% and reddish purple 1.5%.
Context
Analysis performed according to IDS-CMP-2025 [3]: (a) colours named by Munsell and ISCC-NBS, areas and flat areas, (b) texture, (c) brightness and contrast, (d) spatial distribution. Source image: 1885x2591 pixels. Analysis date: 2025-10-03.
A) Color Analysis
Flat areas
Ranked by contrast with their surroundings (CIEDE2000). Strokes thinner than 10 pixels are excluded (1).
| Rank |
Colour |
ISCC-NBS name |
Munsell |
Area |
Contrast |
Position |
| 1 |
A88B96 |
light grayish purplish red |
6.5RP 6.0/3.4 |
1.4% |
43.3 |
on the left |
| 2 |
C0B4B8 |
grayish purplish pink |
2.1RP 7.4/2.3 |
0.5% |
38.8 |
in the centre |
| 3 |
358E97 |
moderate greenish blue |
0.2B 5.3/5.5 |
12% |
35.1 |
on the left |
| 4 |
370D1F |
very dark red |
3.1R 0.9/3.9 |
31% |
24.2 |
at the bottom |
| 5 |
320C32 |
very dark reddish purple |
9.9P 1.1/5.9 |
0.8% |
23.4 |
at the top right |
| 6 |
240B22 |
very dark reddish purple |
9.8P 0.7/2.9 |
1.1% |
20.7 |
at the top |
| 7 |
624F82 |
moderate violet |
2.1P 3.7/7.4 |
53% |
14.7 |
at the top |
Colour name families
| Family |
Area |
| violet |
52% |
| red |
27% |
| blue |
12% |
| brown |
5.0% |
| purple |
1.8% |
| reddish purple |
1.5% |
B) Texture Analysis
| Metric |
Value |
| Global Roughness |
0.142 |
| Mean Local Roughness |
0.014 |
| Roughness Uniformity |
0.017 |
| Edge Density |
0.026 |
| Mean Gradient Magnitude |
0.096 |
| Gradient Variance |
0.024 |
| Gradient Smoothness |
0.0 |
| Directional Coherence |
0.072 |
| Pattern Complexity |
0.132 |
| Pattern Repetition |
1.0 |
| Detail Frequency Ratio |
0.669 |
| Spatial Variation |
0.112 |
| Texture Consistency |
0.374 |
C) Brightness & Contrast Analysis
| Metric |
Value |
| Mean Brightness |
0.289 |
| Brightness Variance |
0.142 |
| Brightness Uniformity |
0.509 |
| Brightness Skewness |
-0.11 |
| Brightness Entropy |
6.444 |
| Rms Contrast |
0.142 |
| Michelson Contrast |
1.0 |
| Weber Contrast |
0.8 |
| Mean Local Contrast |
0.014 |
| Contrast Uniformity |
0.0 |
| Dynamic Range |
1.0 |
| Effective Dynamic Range |
0.388 |
| Shadow Percentage |
50.192 |
| Midtone Percentage |
49.263 |
| Highlight Percentage |
0.545 |
| Shadow Clipping |
0.002 |
| Highlight Clipping |
0.0 |
| Tonal Balance |
0.0 |
| Fine Contrast |
0.008 |
| Medium Contrast |
0.018 |
| Coarse Contrast |
None |
| Multiscale Contrast Ratio |
1.0 |
| Edge Contrast |
0.096 |
| Contrast Clustering |
0.626 |
D) Spatial Distribution Analysis
| Metric |
Value |
| Spatial Coherence |
0.749 |
| Color Clustering |
0.713 |
| Color Transition Smoothness |
0.733 |
| Transition Uniformity |
0.824 |
| Sharp Transition Ratio |
0.1 |
| Transition Directionality |
0.083 |
| Mean Saturation |
0.539 |
| Saturation Variance |
0.035 |
| Low Saturation Ratio |
0.025 |
| Medium Saturation Ratio |
0.71 |
| High Saturation Ratio |
0.265 |
| Saturation Clustering |
0.999 |
| Hue Concentration |
0.701 |
| Complementary Balance |
0.0 |
| Analogous Dominance |
0.854 |
| Temperature Bias |
0.209 |
Methodology
Computational analysis of a photograph of the artwork, reduced to 1,000 pixels on its longer side and filtered by a 3×3 median to remove grain. Colours: each pixel (sRGB rounded to 5 bits per channel) receives its Munsell notation and ISCC-NBS name from a table computed once from published data (Munsell renotation; ISCC-NBS blocks, NBS Special Publication 440, 1976), never from the artworks. Flat areas: connected regions of one name, merged with their neighbours while the CIEDE2000 difference between their mean colours stays below 10; an area is kept from 0.05% of the image; contrast with the surroundings measured 4 to 12 pixels from the edge. Texture: intensity standard deviation, local standard deviation, edge density (Canny), local binary patterns. Brightness: mean, variance, RMS, Michelson and local contrast, shadow / midtone / highlight distribution. Distribution: spatial coherence, transitions, saturation. Methods are deterministic and reproducible. Limits: the measurement concerns the photograph, including its lighting and white balance; two neighbouring areas less than 10 apart are merged.
