Black spots appear when a portion of the shape is not being registered by the Comb App. Most commonly, they occur because you're scanning too close to the subject. If this happens, slowly back away until the spots disappear.
In general, scanning too close to the subject can lead to other scanning-issues such as:
- loss of tracking
- disappearance
- shelling/onion-skin
Should these issues occur during a scan, simply end the session and begin again.