I think I know the meanings of \baselineskip
, \lineskip
and \lineskiplimit
in TeX, I also know \baselineskip
, \baselinestretch
, \linespread
and the second argument of \fontsize
in LaTeX. However, I get confused when I meet the phrase 'double spacing' and setspace
package.
The question is, which dimension is doubled? Is it \baselineskip
, or the skip between bottom and top of the two lines (something like \lineskip
), or some dimension else?
I read the article about leading in Wikipedia. It seems that the original meaning of leading
is \lineskip
. In Bringhurst's book (The Elements Of Typographic Style), \baselineskip
is called a basic leading, total leading, while \lineskip
is the added leading, but they are never doubled.
In LaTeX, the basic total leading is the second argument of \fontsize
, which is set to \baselineskip
. For example, normal font size is 10pt with 12pt of \baselineskip
. So, does double spacing mean \linespread{2}
? Or it implies a 10pt + 2x(12pt-2pt) = 14pt of TeX's \baselineskip
, say, \linespread{1.16667}
?
Microsoft Word tells me it should be the former. 'Double' line spacing means \linespread{2}
in LaTeX.
(In word, font size 10pt, single spacing gets 12pt baseline skip; double spacing gets 24pt)
setspace.sty
tells me both are wrong. \doublespacing
is defined as \setstretch{1.667}
. (The value is slightly changed to fit different \baselinespace
)
That is to say, 'double spacing' means the baseline skip is double length of font size. (1.667x12pt = 20pt = 2x10pt.) Why?
(Using setspace
, font size 10pt, \singlespacing
gets 12pt baseline skip; \doublespacing
gets 20pt)
The more I read, the more confused I get. Can anyone help me to clarify the concept?
Best Answer
I had this discussion once with a friend who had a printers education (Sorry, don't know the right english term). I don't remember the details, but basically she said that the
setspace
package doesn't calculate the line spacing correctly by it's universally defined formula. According to her,\linespread{2}
sets the spaces correctly. However, I myself prefersetspace
while working with a 1.5 line space, because I think it looks better. Maybe that was also the authors' intention.(I would be happy if a more sophisticated answer comes along .)