Defining Old Style, Lining, Proportional, and Tabular Figures
Old Style Figures (OsF)
Also called non-lining figures, these Arabic numerals are not all the same height and some extend above and others below the baseline (like the ascenders and descenders on some lowercase letters).
Lining Figures (LF)
A modern style of numerals also known as short ranging figures or regular numerals, lining figures are all the same height and all figures sit on the baseline. They are generally the same height as the uppercase letters in the typeface.
Proportional
With proportional figures, each character may occupy a different amount of horizontal space. A 1 takes up less space than a 5 or a 9.
Tabular (TF)
Tabular figures are monospaced. Each character takes up the same amount of horizontal space.
Designing With Old Style, Lining, Proportional, and Tabular Figures
Proportional Old Style Figures are attractive within a paragraph of text because the varying height visually blends in with the ups and downs of mixed uppercase and lowercase letters. They don’t work as well within text set in all caps. If you like the look, use them in books, newsletters, and brochures. Proportional Lining Figures work well when used with proportional text set in all caps because the numbers will all sit on the baseline with the capital letters. Because the characters have varying widths they don’t work as well in columns of numbers. Tabular Old Style Figures is an option when you like the look of figures with varying heights but you need the numbers to line up in columns such as in financial documents, tables, charts, or numbered lists. Because they are monospaced, tabular figures may not look as well in headlines and other display text that includes numbers. Instead of doing a lot of kerning to close up the extra space around a 1, for instance, go with proportional figures. Tabular Lining Figures keep all your numbers lined up in tables and columns while also lining up horizontally with capital letters and currency symbols. As with Tabular Old Style, these often don’t look as good at display sizes where lining up in columns is not needed.