An Iroko wood sample was sanded to 7 different grits, and its chatoyance was measured at each step.
Step | PZC (Pos. 1) | PZC (Pos. 2) | PZC (Pos. 3) | PZC (Average) |
120-grit | 12.3 | 12.1 | 10.9 | 11.8 |
180-grit | 12.3 | 11.5 | 11.0 | 11.6 |
240-grit | 11.3 | 11.5 | 10.9 | 11.2 |
320-grit | 15.4 | 14.7 | 15.2 | 15.1 |
600-grit | 14.4 | 13.0 | 14.0 | 13.8 |
800-grit | 20.6 | 20.1 | 21.1 | 20.6 |
1500-grit | 25.9 | 25.9 | 25.0 | 25.6 |
Interestingly, chatoyance did not always increase with grit.







Two black walnut samples were then cut and bookmatched to compare the effects of progressive sanding and then finishing.

Sample 1 was subjected to 14 sanding steps (from 80-grit to 10’000 grit) and its chatoyance was measured at each step. Sample 2 was sanded up to 240-grit where its chatoyance was measured. Then they were finished with blonde dewaxed “medium” shellac (2 parts in 13 parts of Alcohol).
Interestingly, chatoyance seems to continuously increase with grit, and even at 10’000 it does not appear to have reached an asymptote. In addition, chatoyance after finishing appears significantly higher on the fine-sanded sample.
Table and chart below summarize the results:







