problems with different margins for odd/even pages and openright does not work

Question

I have two problems.

1. The inner and outer margins on odd pages are different from those on even pages. On even pages the inner margin is a lot bigger. Desired outcome: bigger inner margin on odd pages.
2. My text starts on the left hand side, i.e. odd pages are on the left, even pages are on the right. Desires outcome: the exact opposite.

I try to post relevant code:

\documentclass[openright,titlepage,headsepline,twoside,BCOR18mm,DIV10,11pt]{scrbook}
\usepackage{amsmath,amssymb,amsthm,array,arydshln}
\usepackage[toc,page]{appendix}
\usepackage{multicol}
\usepackage{makeidx}
\usepackage{geometry}
\usepackage{fancyhdr}

\geometry{a4paper}
\newcommand{\blankpage}{
\newpage
\thispagestyle{empty}
\mbox{}
\newpage}

\begin{document}
\pagestyle{fancy}
\fancyhf{}
\pagenumbering{Roman}
\title{title}
\maketitle
\tableofcontents
\clearpage
\blankpage
\pagenumbering{arabic}
\lhead[\thepage]{\nouppercase{\rightmark}}
\rhead[\nouppercase{\leftmark}]{\thepage}
\chapter
...

If necessary, I'm happy to post additional information.

---

Okay, I resolved 1. in the most embarrising way. It turns out, one should not check margins on his/her computer, if the pdf viewer cuts off a part of the page - after I noticed the horizontal scroll bar, I really felt ashamed.

Anyway, problem number 2 still persits. My text starts on the left hand side, and no matter what I do, there is no way to change it.

Answer 1

First of all you should either rely on scrbook methods for setting the page parameters (via the document class options and possibly the typearea package) or use geometry. With the call

\usepackage{geometry}
\geometry{a4paper}

you're overriding the options BCOR18mm,DIV10.

Let's see what you get without geometry (even page on the left, odd on the right):

Here's what you get with geometry (same layout):

As you can see the layouts are rather different.

The geometry package adopts a "2-3" division: the horizontal space in the page after subtracting the line width and the binding correction (to be specified with the option bindingoffset=<length>) is divided in five parts; two are for the inner margin, three for the outer margin. The same for the top and bottom margin. The line width depends on the main font size.

The scrbook class, by itself, computes the margins and the line width in a combined way; DIVn (where n is an integer) means:

1. Subtract the binding correction (specified with BCOR) from the paper width;

2. Divide the remaining space into n parts, both horizontally and vertically;

3. On an odd page, the leftmost vertical strip is the left (inner) margin and the two rightmost strips the right (outer) margin;

4. On an even page do the reverse;

5. The uppermost horizontal strip is the top margin (where also the headers will sit), the two lowermost horizontal strips is the bottom margin.

Both methods, by default, reserve more space for the outer margin and there are very good reasons for this. One, most commonly stated, is that the inner margin appears "doubled" when the book is flat open; another is that when you keep a book in your hands, the thumbs cover the outer margin; another is that the outer margin is frequently used for annotations.

History has proved that having wider outer margins is useful (and not only the well known affair with Fermat and his unfortunately too narrow margin).