Computational analysis of the photograph of the artwork Eb Major - Research on Harmony - Variation 3 (AQC0728) [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 23 flat areas. The largest are moderate reddish orange (27%), dark purple (17%) and dark grayish blue (13%). Among the others, those that stand out most sharply from their surroundings are very pale purple in the centre (0.1%), moderate purple in the centre (0.3%) and dark grayish reddish brown at the top (0.5%). By colour name family: orange 31%, purple 23%, gray 17%, orange yellow 11%, blue 6.7%, reddish purple 2.5%, black 2.4%, brown 2.0%, pink 1.6%, red 1.5% and violet 1.2%.
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: 2983x3978 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 (6).
| Rank |
Colour |
ISCC-NBS name |
Munsell |
Area |
Contrast |
Position |
| 1 |
373941 |
dark grayish blue |
1.3PB 2.5/1.3 |
13% |
42.4 |
on the left |
| 2 |
DEDFE8 |
very pale purple |
9.6PB 8.8/2.6 |
0.1% |
42.2 |
in the centre |
| 3 |
6F5483 |
moderate purple |
3.1P 3.9/6.6 |
0.3% |
40.6 |
in the centre |
| 4 |
312C29 |
dark grayish reddish brown |
8.3R 1.9/0.6 |
0.5% |
38.7 |
at the top |
| 5 |
CFBDE7 |
very light purple |
3.4P 7.8/5.6 |
0.5% |
35.4 |
at the top |
| 6 |
7A5578 |
moderate purple |
8.0P 4.1/6.2 |
0.3% |
31.3 |
in the centre |
| 7 |
5B3B5F |
dark purple |
8.2P 3.0/4.6 |
17% |
31.3 |
at the bottom right |
| 8 |
B47241 |
brownish orange |
5.0YR 5.4/7.0 |
0.1% |
31.1 |
at the top |
| 9 |
D1C5B4 |
yellowish gray |
8.0YR 7.9/1.7 |
2.8% |
29.8 |
at the top left |
| 10 |
BB93C5 |
light purple |
6.5P 6.6/7.3 |
5.9% |
27.9 |
at the top left |
| 11 |
614872 |
moderate purple |
4.2P 3.6/5.3 |
1.0% |
27.7 |
at the top |
| 12 |
C6BBA7 |
yellowish gray |
4.5Y 7.6/1.7 |
0.5% |
26.6 |
at the top right |
| 13 |
DEBA9D |
pale orange yellow |
7.8YR 7.8/3.5 |
1.6% |
26.1 |
in the centre |
| 14 |
EDA827 |
strong orange yellow |
0.5Y 7.4/11.1 |
11% |
24.6 |
at the bottom |
| 15 |
F0AB2F |
strong orange yellow |
9.4YR 7.5/11.3 |
0.3% |
22.9 |
at the top |
| 16 |
C3BAAD |
yellowish gray |
2.4Y 7.6/1.2 |
11% |
22.1 |
at the bottom left |
| 17 |
6D564D |
grayish reddish brown |
2.1YR 3.7/2.0 |
0.1% |
18.2 |
at the bottom right |
| 18 |
735687 |
moderate purple |
5.0P 4.0/6.9 |
0.7% |
15.2 |
in the centre |
| 19 |
BE651F |
deep orange |
4.1YR 5.1/10.4 |
3.1% |
14.0 |
in the centre |
| 20 |
483243 |
dark reddish purple |
2.2RP 2.5/2.7 |
0.1% |
11.3 |
in the centre |
| 21 |
443261 |
moderate violet |
0.7P 2.5/6.4 |
0.8% |
10.5 |
in the centre |
| 22 |
B86448 |
moderate reddish orange |
9.4R 5.1/8.2 |
27% |
9.6 |
on the right |
| 23 |
B16E37 |
brownish orange |
4.8YR 5.2/8.1 |
1.4% |
5.1 |
at the top |
Colour name families
| Family |
Area |
| orange |
31% |
| purple |
23% |
| gray |
17% |
| orange yellow |
11% |
| blue |
6.7% |
| reddish purple |
2.5% |
| black |
2.4% |
| brown |
2.0% |
| pink |
1.6% |
| red |
1.5% |
| violet |
1.2% |
B) Texture Analysis
| Metric |
Value |
| Global Roughness |
0.194 |
| Mean Local Roughness |
0.023 |
| Roughness Uniformity |
0.022 |
| Edge Density |
0.111 |
| Mean Gradient Magnitude |
0.172 |
| Gradient Variance |
0.05 |
| Gradient Smoothness |
0.0 |
| Directional Coherence |
0.013 |
| Pattern Complexity |
0.118 |
| Pattern Repetition |
1.0 |
| Detail Frequency Ratio |
0.651 |
| Spatial Variation |
0.144 |
| Texture Consistency |
0.465 |
C) Brightness & Contrast Analysis
| Metric |
Value |
| Mean Brightness |
0.481 |
| Brightness Variance |
0.194 |
| Brightness Uniformity |
0.596 |
| Brightness Skewness |
0.016 |
| Brightness Entropy |
7.323 |
| Rms Contrast |
0.194 |
| Michelson Contrast |
1.0 |
| Weber Contrast |
0.688 |
| Mean Local Contrast |
0.024 |
| Contrast Uniformity |
0.058 |
| Dynamic Range |
1.0 |
| Effective Dynamic Range |
0.576 |
| Shadow Percentage |
31.341 |
| Midtone Percentage |
42.607 |
| Highlight Percentage |
26.051 |
| Shadow Clipping |
0.001 |
| Highlight Clipping |
0.003 |
| Tonal Balance |
0.074 |
| Fine Contrast |
0.013 |
| Medium Contrast |
0.03 |
| Coarse Contrast |
0.04 |
| Multiscale Contrast Ratio |
0.319 |
| Edge Contrast |
0.172 |
| Contrast Clustering |
0.535 |
D) Spatial Distribution Analysis
| Metric |
Value |
| Spatial Coherence |
0.764 |
| Color Clustering |
0.473 |
| Color Transition Smoothness |
0.555 |
| Transition Uniformity |
0.667 |
| Sharp Transition Ratio |
0.1 |
| Transition Directionality |
0.017 |
| Mean Saturation |
0.435 |
| Saturation Variance |
0.063 |
| Low Saturation Ratio |
0.36 |
| Medium Saturation Ratio |
0.465 |
| High Saturation Ratio |
0.175 |
| Saturation Clustering |
0.999 |
| Hue Concentration |
0.678 |
| Complementary Balance |
0.027 |
| Analogous Dominance |
0.65 |
| Temperature Bias |
0.658 |
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.
