White pencils are used to trace pictures and designs on to parchment. It is important that the the point is very sharp so that the line is fine for detailed work. A lot of people prefer mechanical pencils and you can buy white leads for this purpose from various web sites selling parchment equipment. I have found that the only mechanical pencil that is offered on parchment sites is SumoGrip, I found that the lead was really difficult to replace and there were no instructions however the grip is quite comfortable.
When I was looking for an alternative mechanical pencil I came across
After checking the reviews and finding out a lot more about mechanical pencils! I settled for a Pentel Sharp Kerry it is quite expensive but easy to load and it has a pen top for travelling. About £12.00 from Amazon.
White pencils by Pergamano are about £1.35
SumoGrip pencils are £6.89
White leads are £3.95 (why so expensive?)