1. Leakage of Light in Diamonds and Its Estimation
2. Stereoview: Stereovision and evaluation of leakage
3. Taking into account the features of human perception
4. Brilliance
5. Light Return
6. Contrast

Constrast

This parameter is experimental. We did not finish testing and learning of this function yet. We would very appreciate if you report us how it corresponds with your own impression.

Please note that we do not allow calculation of contrast for stones less than 1.5 mm in diameter, because the contrast for so tiny stones is indeterminate.

For the cut of any type all cut quality parameters, including contrast, are normalized to the values of these parameters determined for the round brilliant cut with the modern Tolkowsky parameters. (To set this cut in DiamCalc choose brilliant cut and select "Cut-Load proportions-Modern Tolkowsky" menu item.)
The diameter of the ideal round cut is taken the same as the analyzed cut diameter.
Thus, the displayed values are not absolute, but relative. If the decrease of mass of the simple cut (with small number of sides) causes the increase of the contrast parameter value, it doesn't always mean that the absolute contrast of this cut has increased when the mass was decreased. It means that the contrast of the ideal round brilliant cut has decreased more significantly than the contrast of the analyzed cut during the mass decrease.

We understand that someone may find this normalization too sophisticated, be we think that normalization without mass correction or the absence of the normalization at all will lead to even more misunderstanding of the parameter values we calculate.

We would appreciate suggestions for implementation of other normalization principles.