If the desired size of type and the line length used in the page layout are incompatible, one of them probably needs to change. Typically it is the font size that gets adjusted but don’t be afraid to re-evaluate your page layout to accommodate wider or narrower text columns.
Line length is not the only consideration. The shape of the font, letter spacing, and word spacing also affect readability and help in determining the best line length.
The Bottomline: The line length rule applies primarily to body copy. Headlines, subheadings, and other small bits of text have more flexibility. Almost any reasonable line length will work in a design if combined with the right size font. The longer the line, the larger the font can be. The shorter the line, the smaller the font can be.
