Computational analysis of the photograph of the artwork Ab Major - Research on Harmony - Variation 1 (AQC0608) [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 11 flat areas. The largest are grayish blue (66%), light violet (14%) and deep violet (7.8%). Among the others, those that stand out most sharply from their surroundings are vivid reddish orange at the top left (0.4%), vivid red on the left (2.0%) and light blue on the left (0.2%). By colour name family: blue 66%, violet 24%, gray 6.0%, green 1.6%, orange 1.5% and red 1.1%.
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: 2598x3248 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 (0).
| Rank |
Colour |
ISCC-NBS name |
Munsell |
Area |
Contrast |
Position |
| 1 |
D74022 |
vivid reddish orange |
8.8R 4.9/14.0 |
0.4% |
38.1 |
at the top left |
| 2 |
C12F15 |
vivid red |
8.6R 4.3/14.5 |
2.0% |
33.5 |
on the left |
| 3 |
6EC6E9 |
light blue |
9.2B 7.5/7.6 |
0.2% |
32.1 |
on the left |
| 4 |
E5DED5 |
yellowish white |
7.9YR 8.8/0.8 |
0.1% |
27.1 |
on the left |
| 5 |
425563 |
grayish blue |
2.0PB 3.4/2.5 |
66% |
24.9 |
in the centre |
| 6 |
352659 |
deep violet |
9.8PB 1.9/7.8 |
7.8% |
22.8 |
at the bottom left |
| 7 |
9B95B2 |
pale violet |
1.5P 6.2/4.5 |
3.0% |
22.0 |
on the left |
| 8 |
7C6AA7 |
light violet |
1.2P 4.8/7.5 |
14% |
16.6 |
in the centre |
| 9 |
808A8F |
greenish gray |
8.4BG 5.7/0.6 |
2.7% |
9.3 |
at the top right |
| 10 |
7C868B |
bluish gray |
2.2PB 5.4/1.4 |
3.1% |
7.8 |
at the top left |
| 11 |
6B757D |
bluish gray |
2.0PB 4.7/1.4 |
0.1% |
5.4 |
at the bottom left |
Colour name families
| Family |
Area |
| blue |
66% |
| violet |
24% |
| gray |
6.0% |
| green |
1.6% |
| orange |
1.5% |
| red |
1.1% |
B) Texture Analysis
| Metric |
Value |
| Global Roughness |
0.147 |
| Mean Local Roughness |
0.062 |
| Roughness Uniformity |
0.041 |
| Edge Density |
0.291 |
| Mean Gradient Magnitude |
0.462 |
| Gradient Variance |
0.183 |
| Gradient Smoothness |
0.075 |
| Directional Coherence |
0.008 |
| Pattern Complexity |
0.162 |
| Pattern Repetition |
1.0 |
| Detail Frequency Ratio |
0.718 |
| Spatial Variation |
0.08 |
| Texture Consistency |
0.62 |
C) Brightness & Contrast Analysis
| Metric |
Value |
| Mean Brightness |
0.36 |
| Brightness Variance |
0.147 |
| Brightness Uniformity |
0.591 |
| Brightness Skewness |
1.134 |
| Brightness Entropy |
7.097 |
| Rms Contrast |
0.147 |
| Michelson Contrast |
1.0 |
| Weber Contrast |
0.627 |
| Mean Local Contrast |
0.07 |
| Contrast Uniformity |
0.359 |
| Dynamic Range |
1.0 |
| Effective Dynamic Range |
0.467 |
| Shadow Percentage |
50.455 |
| Midtone Percentage |
45.254 |
| Highlight Percentage |
4.291 |
| Shadow Clipping |
0.0 |
| Highlight Clipping |
0.02 |
| Tonal Balance |
0.0 |
| Fine Contrast |
0.031 |
| Medium Contrast |
0.084 |
| Coarse Contrast |
0.081 |
| Multiscale Contrast Ratio |
0.389 |
| Edge Contrast |
0.462 |
| Contrast Clustering |
0.38 |
D) Spatial Distribution Analysis
| Metric |
Value |
| Spatial Coherence |
0.709 |
| Color Clustering |
0.457 |
| Color Transition Smoothness |
0.0 |
| Transition Uniformity |
0.0 |
| Sharp Transition Ratio |
0.1 |
| Transition Directionality |
0.007 |
| Mean Saturation |
0.349 |
| Saturation Variance |
0.024 |
| Low Saturation Ratio |
0.345 |
| Medium Saturation Ratio |
0.62 |
| High Saturation Ratio |
0.035 |
| Saturation Clustering |
0.997 |
| Hue Concentration |
0.867 |
| Complementary Balance |
0.015 |
| Analogous Dominance |
0.966 |
| Temperature Bias |
-0.68 |
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.
