Not all fountain pens are calligraphy pens, and not all calligraphy pens are fountain pens. The style of writing a fountain pen will produce is found a) in your individual writing style and ability and b) the type of nib it has.
Most fountain pens are fitted with a rounded nib and are available in extra fine, fine, medium or broad sizes. It is important to note that, while the broader the nib the thicker the line size, this doesn’t necessarily correlate to line variation or calligraphic effect. Read more on line variation…
If you are determined to achieve a more flourished, calligraphic writing style, try a fountain pen fitted with an italic nib. Also known as a ’stub’ these have a flat tip, sometimes angled, and are available in varying widths.
Words by: Ben Graham
Image Source: https://www.lamy.com/en/lamy-nib-guide/