[Tex/LaTex] Inconsistent Vertical Spacing Using Multicol

multicolspacingvertical alignment

I've been getting random vertical spaces between paragraphs using multicol. Oddly enough, if I change the margins to 1cm I get perfect spacing. The problem gets worse if I attempt to add an asterisk to multicols to produce uneven columns on the last page, but this only occurs when there is the right amount of text present.

For example, if I enter the following script I get two random spaces between paragraphs on the third page. Additionally, if I want to reproduce the spacing problem with uneven columns on the last page, I get large gaps in text after shortening up the text by using \lipsum[1] and adding the asterisk to multcols.

I'm pretty new to LaTeX and really ejoying the typesetting experience so far. I appreciate any help I can get. 

\documentclass[twoside]{article}
\usepackage{indentfirst}
\usepackage[sc]{mathpazo}
\usepackage[T1]{fontenc}
\usepackage{amsmath}
\usepackage{lipsum}
\usepackage[margin={1in,1in}]{geometry}
\usepackage{multicol}
\usepackage{abstract}
\renewcommand{\abstractnamefont}{\normalfont\bfseries}
\usepackage{titlesec}
\titleformat{\section}[block]{\large\scshape\centering}{\thesection.}{1em}{}
\title{\vspace{-15mm}\fontsize{24pt}{10pt}\selectfont\textbf{The Effect of c-Jun N-   terminal Kinase  Inhibition on Oct4 Promoter Activity}}   
\author{\large\textsc{Daniel D} \\[2mm]\normalsize  Sate University \\\vspace{-5mm}}    
\date{}
\begin{document}
\maketitle
\frenchspacing
\setlength\parindent{10pt}
\begin{abstract}
\noindent \textbf{ \lipsum[3]} 
\end{abstract}
\begin{multicols}{2}
\section*{Introduction}
\lipsum 

\lipsum
\section*{Materials and Methods}
\lipsum 
\section*{Results}
\lipsum 

\lipsum
\section*{Discussion}
\lipsum 
\end{multicols}
\end{document}

Best Answer

The reason for these "random spaces" is as a result of the particular document composition. Take a look at pages 3 and 4:

enter image description here

Note that you have a heading \section*{Results} which happen to be at the top of the first column of page 4. TeX decided that there is no way to place this heading together with at least one line "Lorem ipsum dolor sit amet, consectetuer adip-" at the bottom of column 2 on page 3. There is just not enough room. And, in order to avoid a hanging sectional heading at the bottom of a column, it pushed everything to the top of the following column.

However, since you requested to have flush-bottom columns (using the non-starred multicols environment), the only alternative is to add space where space is available - around sectional headings, or between paragraphs. The latter is the first I looked, as it is evident that it is occurring in column 2. For this, look at the value of \parskip:

\showthe\parskip
> 0.0pt plus 1.0pt

This means that TeX can stretch the space between paragraphs by up to 1pt, partly explaining the gaps between the paragraphs. You'll see a completely different picture in the output if you \setlength{\parskip}{0pt} in your preamble:

enter image description here

Of course, this affects other components of your document as well, so I wouldn't make such an explicit change.

My suggestion would be to disregard such odd spaces until the end of your document processing. If these problems persist in your final document, then you can address them with more aggressive means. Typically a mild change in your textual presentation clears up these problems.

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