Table 6 Comparison of colorimetric CIELab data of standard fabricated frescoes using standard black pigments and the same data found for the black pigment of the old Roman fresco.
Identification of a black pigment used in the old Roman fresco by means of CIELab parameters (values are the mean of three determinations) | ||||
|---|---|---|---|---|
Sample | Illuminating | L | a* | b* |
Black-Ivory | D 65 D 50 | 29.71±1.34 27.44±2.57 | 0.11±0.02 0.08±0.03 | -0.29±0.09 -0.37±0.16 |
Black-Carbon P | D 65 D 50 | 33.12±1.11 32.87±0.54 | -0.29±0.03 -0.76±0.03 | -3-15±0.24 -3.33±0.21 |
Black-Carbon Z | D 65 D 50 | 41.28±0.65 40.96±0.61 | -0.44±0.02 -1.05±0.04 | -4.15±0.09 -4.24±0.15 |
Black-Vine | D 65 D 50 | 29.15±0.61 29.37±0.46 | 0.16±0.02 0.21±0.03 | 0.38±0.14 0.35±0.12 |
Black old Roman fresco | D 65 D 50 | 28.81±0.89 28.54±0.34 | 0.42±0.05 0.52±0.04 | 2.28±0.17 2.88±0.19 |
Measurements performed by spectrophotometer Minolta CM2600d, standard observatory 2°, MAV mask. Illuminants: D 65 (European standard) and D 50 (American standard). | ||||