Computational analysis of the photograph of the artwork Ab minor - Research on Harmony - Variation 4 (AQC0691) [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 13 flat areas. The largest are dark blue (23%), grayish blue (18%) and dark purplish blue (15%). Among the others, those that stand out most sharply from their surroundings are strong yellow at the top (0.3%), moderate yellow in the centre (2.4%) and light greenish gray in the centre (0.7%). By colour name family: blue 58%, brown 6.8%, yellow brown 5.1%, reddish purple 4.4%, gray 4.2%, violet 3.8%, red 3.8%, olive brown 3.4%, olive gray 2.9%, yellow 2.6%, purple 2.3% and olive 2.0%.
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: 2281x2281 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 |
DDC14A |
strong yellow |
5.8Y 7.8/8.5 |
0.3% |
32.0 |
at the top |
| 2 |
E3C35E |
moderate yellow |
4.0Y 7.9/7.8 |
2.4% |
31.9 |
in the centre |
| 3 |
A9B0A5 |
light greenish gray |
6.9GY 7.1/1.2 |
0.7% |
28.8 |
in the centre |
| 4 |
D2B3AA |
grayish yellowish pink |
8.9R 7.5/2.8 |
0.4% |
28.1 |
at the top |
| 5 |
423838 |
dark reddish gray |
6.2R 2.6/0.6 |
1.1% |
18.7 |
at the bottom |
| 6 |
2B2A40 |
dark purplish blue |
8.1PB 1.9/3.2 |
15% |
18.2 |
at the top right |
| 7 |
86687C |
grayish reddish purple |
1.0RP 4.7/3.1 |
9.2% |
16.2 |
at the bottom left |
| 8 |
5A6B81 |
grayish blue |
4.3PB 4.4/3.6 |
6.7% |
15.1 |
at the bottom left |
| 9 |
4D5F6E |
grayish blue |
2.1PB 3.8/2.6 |
18% |
13.4 |
in the centre |
| 10 |
564639 |
grayish brown |
5.3YR 3.0/1.5 |
12% |
11.2 |
at the top left |
| 11 |
31446D |
dark blue |
6.2PB 2.9/5.5 |
23% |
9.3 |
at the bottom right |
| 12 |
665D5A |
dark reddish gray |
3.9R 3.9/0.6 |
0.1% |
8.2 |
at the bottom left |
| 13 |
797665 |
light olive brown |
3.6Y 4.8/1.4 |
10% |
6.2 |
at the top left |
Colour name families
| Family |
Area |
| blue |
58% |
| brown |
6.8% |
| yellow brown |
5.1% |
| reddish purple |
4.4% |
| gray |
4.2% |
| violet |
3.8% |
| red |
3.8% |
| olive brown |
3.4% |
| olive gray |
2.9% |
| yellow |
2.6% |
| purple |
2.3% |
| olive |
2.0% |
B) Texture Analysis
| Metric |
Value |
| Global Roughness |
0.124 |
| Mean Local Roughness |
0.006 |
| Roughness Uniformity |
0.016 |
| Edge Density |
0.013 |
| Mean Gradient Magnitude |
0.045 |
| Gradient Variance |
0.017 |
| Gradient Smoothness |
0.0 |
| Directional Coherence |
0.259 |
| Pattern Complexity |
0.102 |
| Pattern Repetition |
1.0 |
| Detail Frequency Ratio |
0.676 |
| Spatial Variation |
0.097 |
| Texture Consistency |
0.133 |
C) Brightness & Contrast Analysis
| Metric |
Value |
| Mean Brightness |
0.335 |
| Brightness Variance |
0.124 |
| Brightness Uniformity |
0.629 |
| Brightness Skewness |
1.367 |
| Brightness Entropy |
6.48 |
| Rms Contrast |
0.124 |
| Michelson Contrast |
1.0 |
| Weber Contrast |
0.605 |
| Mean Local Contrast |
0.006 |
| Contrast Uniformity |
0.0 |
| Dynamic Range |
0.984 |
| Effective Dynamic Range |
0.337 |
| Shadow Percentage |
52.244 |
| Midtone Percentage |
44.768 |
| Highlight Percentage |
2.989 |
| Shadow Clipping |
0.0 |
| Highlight Clipping |
0.0 |
| Tonal Balance |
0.0 |
| Fine Contrast |
0.004 |
| Medium Contrast |
0.008 |
| Coarse Contrast |
None |
| Multiscale Contrast Ratio |
1.0 |
| Edge Contrast |
0.045 |
| Contrast Clustering |
0.867 |
D) Spatial Distribution Analysis
| Metric |
Value |
| Spatial Coherence |
0.825 |
| Color Clustering |
0.444 |
| Color Transition Smoothness |
0.874 |
| Transition Uniformity |
0.893 |
| Sharp Transition Ratio |
0.1 |
| Transition Directionality |
0.275 |
| Mean Saturation |
0.343 |
| Saturation Variance |
0.019 |
| Low Saturation Ratio |
0.412 |
| Medium Saturation Ratio |
0.584 |
| High Saturation Ratio |
0.004 |
| Saturation Clustering |
1.0 |
| Hue Concentration |
0.485 |
| Complementary Balance |
0.198 |
| Analogous Dominance |
0.7 |
| Temperature Bias |
-0.259 |
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.
