Scratching or catching nibs

Nib scratching or catching (digging into the paper) could be due the the quality of the paper being used, check to see that you are using a high quality paper. If so, try changing your nib, or adjusting your writing style.

Since the nibs used for pointed pen Calligraphy (Spencerian and Copperplate) have a very sharp point and will tend to dig into the paper on the upstroke if you are using to much pressure, so a light touch is required which take practice.

If you are holding the pen at a steep angle as used for ballpoint pens this will tend to cause the nib of the dip pen and fountain pen to catch (dig in) so by changing to a shallower angle will solve this problem.