Characters Per Line

Questions & Answers

What is the article "Characters Per Line" about?

The article discusses the importance of characters per line (CPL) in typography for readability and introduces a mathematical method to precisely calculate the required line width for a desired CPL and font size. It critiques imprecise approaches to setting column widths.

Who would benefit from reading this article on CPL?

This article is for designers, typographers, and web developers who want to apply a precise, data-driven approach to setting text column widths for optimal readability, rather than relying on trial-and-error.

How does the method presented in this article differ from traditional approaches to CPL?

Unlike traditional trial-and-error methods or broad "optimal" CPL ranges, this article proposes a programmatic, mathematical approach. It introduces a "character constant" specific to each font, enabling precise calculation of line width for a target CPL and font size.

When should one use the CPL prediction method described in the article?

The CPL prediction method should be used when a designer wants to ensure their typography dictates the column width, rather than the other way around, to achieve a specific and optimal character count per line for readability across different font sizes.

What is a "character constant" and how is it used in CPL prediction?

A "character constant" (μ) is a unique value for each font that relates its font size to the average width of its characters. It allows for the mathematical prediction of line width by dividing the desired CPL by this constant to get a width factor, then multiplying by the font size.