# How and when to remove the space on the left hand of the beginning of a paragraph?

I have something like that:

\section{subsection}
...
\begin{figure}
...
\end{figure}
texttexttext
...


It turns out that it does not put the "texttexttext" on the very left hand side... it leaves some space... My questions are:

1. How to remove this space?

2. Generally speaking, in a technical report, when should we leave some space on the left hand side of the beginning of a paragraph? when shouldn't we?

3. If we leave some space the left hand side of the beginning of a paragraph, should we leave a blank line above it to separate from the previous paragraph?

4. Also, what is the best way to add a blank line? \\[1em]?

I would like to know the convention.

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Could you be a bit more specific about (4). That is, do you want a general skip between paragraphs of a specific length (say 1em)? –  Werner Aug 17 '11 at 19:44

1. In answer to your first question, this space is 'provided' by \parindent and indents the paragraph by a certain amount. In order to remove it, prepend the paragraph with \noindent. Some more information on practical and not-so-practical global changes that affect \parindent, read the UK TeX FAQ entry on 'Zero paragraph indent'.

2. Your second question deals more about personal preference, since there are many documents I've seen that use either an indent or not. Regardless of the choice, even from a technical point of view, consistency should reign supreme.

3. LaTeX provides some guidelines as to where this indentation occurs or not. Some macros (like sectional commands, to name one) end using \noindent (and sometimes \ignorespacesafterend) to drop the indent from the paragraph following the command. Perhaps as a prime example, consider the titlesec package. Adjusting the spacing around sectional commands <command> is performed by means of

\titlespacing[*]{<command>}{<left>}{<before-sep>}{<after-sep>}[right>]


The starred * version specifically kills the indentation of the paragraph following <command>. Again, with the choice left up to the user/typesetter, this could be considered personal preference.

4. In order to produce an empty line you could use

... orci velit, suscipit quis congue at, laoreet vitae elit.

\mbox{}% Creates an empty box

Lorem ipsum dolor sit amet, consectetur ...


However, this will necessarily create an empty-line paragraph, and therefore have a \parskip above and below the line. Although the use of \\[<len>] works in text mode for paragraph spacing, is typically used in tabular and array environments. For vertical whitespace of a specific length, use \vspace*{<len>}. You will notice LaTeX complaining about Underfull \hbox (badness 10000) in paragraph at lines ... though, which should identify incorrect usage of spacing associated with line breaking.

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The "space" you are referring to is the paragraph indent, and it is automatically added to each new paragraph (which in your LaTeX source is created by adding a blank line between pragraphs.) It may also be added automatically at the end of certain environments.

The default for most document classes is to indent every new paragraph except for those immediately following a chapter/section/subsection heading.

1. To remove the indent in a single paragraph, use the \noindent command. You shouldn't generally need to do this, however. If you find indented paragraphs after an environment (e.g. displayed math) that you don't need, you should make sure there is no blank line in your source after the environment. It's helpful to insert a % on a line by itself in these cases to make your source more readable.
2. When to break a paragraph and when not to is a writing question: it has no direct objective answer, although roughly a paragraph corresponds to a single idea. Here is a link to a reasonable explanation: Paragraphs and paragraphing.
3. If you are indenting new paragraphs, there is no need to insert blank lines in the output between paragraphs. (Of course your source document will use blank lines to separate paragraphs.)
4. In general, you shouldn't use \\ to create blank lines. The \\ command inserts a line break within a single paragraph. As Werner says in his answer, line spacing around headings should be done by the heading definition, and not manually. If you do need to make a blank line, on an exceptional basis, you can insert space with the \bigskip commands (or \vspace{}) command, or but generally you shouldn't have to do this. See What is an elegant way to insert a skip between two paragraphs?.

For some documents (not regular reports/articles/theses/books) it is sometimes appropriate to have no paragraph indentation, and separate paragraphs with blank lines. If you need this kind of format, you should use the parskip package.

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To add to this wonderful answer: I use \setlength{\parindent}{0in} in the preambel to eliminate the need for \noindent altogether. –  kongo09 Aug 17 '11 at 20:59
@kongo09 Unfortunately I don't think this is really a good idea. You need some way to separate paragraphs in your text; either you use a non-zero \parindent or you use a blank line and no par indent. In the latter case, you should use the parskip package, rather than setting \parindent to 0. Also, one of the problems with this latter scheme is that it can lead to ambiguous paragraph breaks at page breaks. (Not as big a problem as people like to claim IMO, but still an issue.) –  Alan Munn Aug 17 '11 at 21:04
You are totally right with respect to normal books or scientific publications (which is the main playground of TeX). However, there are plenty of use-cases where the question of inter-paragraph spacing is totally separate from the indent question. Think, e.g. of a photo collage book without any text or paragraphs. –  kongo09 Aug 17 '11 at 21:18
@kongo09 Perhaps, but if that's the case, you can use \parskip and just not put any blank lines in your source. :-) –  Alan Munn Aug 17 '11 at 21:21