How far apart should lines of text be according to calligraphy standards?

The appropriate spacing between lines of text in calligraphy is established to enhance readability and maintain aesthetic balance. Five and a half pen widths is considered the ideal distance as it permits ample room for the ascenders and descenders of different letterforms, thus preventing them from crowding or interfering with each other. This spacing allows for a clear visual separation between lines, making it easier for the reader to follow the text without distraction. It also ensures that each line is distinct while contributing to an overall harmonious appearance on the page. This careful attention to spacing is fundamental in calligraphy, as it directly affects both the functionality and artistry of the written work.