Ink feathering or bleeding

Since Calligraphy inks are rather wet or runny this can cause the ink to bleed through the paper, or spread out along the fibres of the paper (feathering), these problems are common when using an absorbant paper.

The best type of paper for use with dip pens and fountain pens is a high quality paper such as(Rhodia, photo copier paper etc). as they will tend to absorb the ink more slowly. As a rule of thumb, any paper that is good for  marker pens are also suitable for use with a dip pen or fountain pens. due to their lack of absorbency, and will be less likely to cause your nib to dig into the paper (snag) as you write

If you need to use an absorbent paper you can either buy a thicker ink (Speedball Calligraphy ink) or thicken the ink using gum arabic.