4. Modification of usage properties, quality

The purpose of treatment is to modify the material's macro-scopic or "use" properties. Wood is treated in its mass, and it is therefore possible to re-machine parts without losing the benefits of the treatment. Retification is accompanied by a loss of sample mass coupled with anisotropic volume shrinkage of the structure. On leaving the kiln, retified wood emits an odor similar to that of roasted coffee, which diminishes over the course of a few days and then disappears. One of the most important commercial characteristics is the darkening of the material. Measuring color and mass loss are the simplest tools of quality control.