Painting and Digging can be divided into several categories. For purposes of this article we will discuss the following three primary combinations (others follow in our appendices).

1A. Crown-Only Painting
1B. Crown-Only Digging
2A. Pavilion-Only Painting
2B. Pavilion-Only Digging
3A. Crown & Pavilion Painting
3B. Crown & Pavilion Digging

Measuring Painting & Digging

Painting and digging will be measured in terms of degrees of average deviation from azimuth, or normal indexing. On a standard round brilliant 11.25 degrees (or less depending on configuration) is maximum.

ACP = Average Crown Painting. APP = Average Pavilion Painting

ACD = Average Crown Digging. APD = Average Pavilion Digging

Note: Painting & Digging can also be measured in 'clicks' which correspond to a diamond cutter's tang. 1 click is equivalent to 3.75 degrees. 3 clicks, or 11.25 degrees, is maximum.

ASET Comparison Chart (generated using DiamCalc software by OctoNus)

We believe this charts supports the considerable difference we have observed between crown-only painting (1A) and all other painting & digging categories.

See this link for an explanation of ASET.

1A. Crown-Only Painting: No reduction in performance under the table. Gradual impact occurs along the girdle. In our experience the effects are not visible until ACP of 6-7° degrees (increased greens). The extent to which they are visible depends on overall configuration & optical symmetry. *Note that this applies to “superideal” diamonds with no pavilion painting or digging.

1B. Crown-Only Digging: In our experience reduction in performance begins with ACD >= 3°. Girdle facets fall off in performance especially fast (severe greens).

2A. Pavilion-Only Painting: Visible effects are notable with APP >= 3° (increased greens) and significant darkness under the table appears with APP >= 7° (severe blues).

2B. Pavilion-Only Digging: Reduction in performance under the table with APD >= 2° (severe blues). Girdle facets fall off in performance especially fast (severe greens).

3A. Crown & Pavilion Painting: In our experience visible effects are notable with ACP+APP >= 4°  (increased greens). Significant darkness under the table appears with >= 7° (severe blues).

3B. Crown & Pavilion Digging: Reduction in performance under the table with ACD+APD >= 2° (severe blues). Girdle facets fall off especially fast (severe greens).

Other combination charts appear in Appendices.