This is an example of two fonts with the same x-height, but there is a difference

Below is an image of the two fonts side by side:

Even though the x-heights are the same in both fonts, if you look carefully, Libre Baskerville appears to be slightly larger than Adamina. This is due to the difference in the character widths and spacing of the two fonts.

In Adamina, the character width is narrower than Libre Baskerville, and character spacing is closer together, giving it a more condensed appearance and the optical illusion of being slightly smaller than Libre Baskerville.

You will also notice that Adamina has a greater line height, or space between each line of text, than Libre Baskerville even though they have the same point size. This was how each font was optimized when it was designed, and can be increased or reduced by using the line-height attribute and altering a couple of digits.

If you wished to use Libre Baskerville, or a font similar in x-height and line spacing, and achieve the same line spacing as Adamina, you would need to increase the line height to around 22px, as in the illustration below:

With traditional typesetting using metal type, it was impossible to reduce line spacing and could only be increased by placing thin metal strips of a predetermined thickness between each line of type. Imagine having to do this between hundreds of lines of type!

One way to avoid this was to to set the type on a body larger than the chosen point size. For example, a 12pt typeface on a 14pt body, (12/14pt). This would give an extra 2pt space between each line. In print typography 1pt equals 1/72 of an inch.