Awwww, snap. Here we go. What we will be discussing today is the relationship between points, picas, and inches. What are points and picas and how do they relate to inches you ask? Well here we go…
To the left is a 1 inch line. Dividing that line are 72 smaller lines. These are called points. Points are the smallest unit in typography and many people are familiar with them sense they usually select a point size in their word processor (Think 12 point Times New Roman). There are also 6 larger hash marks hanging ragged left. these 6 hash marks are pica marks. Picas (pronounced pie-ka) are also a typographical unit of measurement composed of 12 points. A pica is equal to 12 points and ⅙ of an inch. Thus, 6 picas is equal to 1 inch (and now you know why the site is called 6picas)
So now does that mean if someone sets a title in 72 point type the letters will be 1 inch high? No. As counterintuitive as it sounds, 72 point letters will not be an inch tall. Looking back at the post Typography 101, letters reside in an em square. If the type size is set to 72 points the em square will be 72 points high. Meaning, from the descender to the ascender roughly 72 points or 1 inch. I say roughly because although the type designer lays out the type in the square, it doesn’t necessarily mean he/she used all the space within for their ascender and descender (including the overshoots). 95% of the time; however, the line height of a 72 point typeface will be an inch high. For example, highlighting the em square in the background, one can see where the baseline , cap-height and the descender are in relation to the overall square.
So What’s the Point?
Although 72pt is equal to an inch, 72 point letters are not an inch tall, but the line height usually is.
point: The smallest unit of measurement in typography (12 points to a pica or 72 points to an inch) Bonus: The point was invented by Pierre Simon Fournier
pica: (pronounced pie-ka) A unit of measurement corresponding to 12 points or 1/6 of an inch.