Cleans up README

README.md

@@ -3,79 +3,112 @@ Twibright Optar
 
 [![Build Status](https://travis-ci.org/colindean/optar.png?branch=master)](https://travis-ci.org/colindean/optar)
 
-This is a program to store data on paper using a 600dpi b/w laser printer and a
+_**Special note:** The repository of optar at http://github.com/colindean/optar 
-600+ dpi scanner.
+exists because I (@colindean) had difficulties finding the source and it seemed
+to be abandoned/dormant. I've made slight improvements over time. Improvements
+welcomed as pull requests._
 
-You need to install ImageMagick so that the resulting .pgm image can be converted into
+This is a program to store data on paper using a 600 dpi black and white laser
-PostScript with the right dimensions (so each pixel is 3x3 600dpi pixels so that
+printer and a 600+ dpi scanner.
-there is no unnecessary jitter).
 
-Make sure you have libpng installed and if you type "libpng-config" on the
+Building
-commandline, there's a program which prints something.
+--------
 
-Compile with ``make``. Become root ``su -`` and type ``make install``. Now you have
+You need to install [ImageMagick](https://www.imagemagick.org) so that the 
-optar, unoptar and pgm2ps installed on your system in /usr/local/bin. Later
+resulting .pgm image can be converted into PostScript with the right dimensions:
-you can uninstall by typing ``make uninstall`` the same way as you typed
+each pixel must be 3x3 600dpi pixels so that there is no unnecessary jitter.
-``make install``.
+
+Make sure you have [libpng](http://libpng.org/pub/png/) installed. You'll know
+that is is installed correctly if you type `libpng-config` on the commandline, 
+there's a program which prints something. Virtually all desktop Linux distros 
+and every macOS system has this installed already.
+
+Compile with
+
+    make
+
+Note that there may be some hardcoded configuration values that you may need to
+change, for example the page size defaults to A4 instead of US Letter. Read on
+to learn where to change that.
+
+Installing locally
+------------------
+
+It's easiest to install your local build with
+
+    sudo make install
+
+`optar`, `unoptar`, and `pgm2ps` installed on your system in `/usr/local/bin`. 
+
+To uninstall, run
+
+    sudo make uninstall
 
 Encoding (writing)
 ------------------
+
 Run
 
-``./optar other_guys.ogg other_guys.ogg``
+    optar other_guys.ogg other_guys.ogg
 
 which will produce files:
 
-* other_guys.ogg_0001.pgm
+```
-* other_guys.ogg_0002.pgm
+other_guys.ogg_0001.pgm
-* other_guys.ogg_0003.pgm
+other_guys.ogg_0002.pgm
-* other_guys.ogg_0004.pgm
+other_guys.ogg_0003.pgm
-* other_guys.ogg_0005.pgm
+other_guys.ogg_0004.pgm
-* other_guys.ogg_0006.pgm
+other_guys.ogg_0005.pgm
+other_guys.ogg_0006.pgm
+```
 
 Now convert them into PostScript using the included pgm2ps tool:
-``./pgm2ps *.pgm``
 
-Print them using a 600dpi (or more) laser printer. Inkjet or dot matrix was
+    pgm2ps *.pgm
-never tested and will not probably work at the pre-defined data density. See
+
-"Changing the format" below.
+Print these using a 600 dpi (or greater resolution) **laser** printer. Inkjet or
+dot matrix was never tested and will not probably work at the pre-defined data 
+density. See "Changing the format" below.
 
 Please note that the file will be padded by zeroes and the original length will
-be lost. Pack your data with tar if you store data that are sensitive to this.
+be lost. **Pack your data with tar if you store data that are sensitive to
+this.**
 
 Decoding (reading)
 ------------------
 
 Clean and polish the scanner glass with rubbing alcohol and paper towel. Put
-yellow pages on the scanner lid to get sharper picture *). Insert the
+yellow pages on the scanner lid to get sharper picture˚. Insert the
 page so that the text on the bottom is upright. Scan the pages into
 PNG (not JPEG!) on 600dpi (or 1200dpi, slightly better):
 
-* scan_0001.png
+```
-* scan_0002.png
+scan_0001.png
-* scan_0003.png
+scan_0002.png
-* scan_0004.png
+scan_0003.png
-* scan_0005.png
+scan_0004.png
-* scan_0006.png
+scan_0005.png
+scan_0006.png
+```
 
 Read the number sequence (format specification) from any of the papers and feed
 it as 1st argument to the optar, 2nd argument is the filename part before the
 underscore:
 
-``unoptar 0-65-93-24-3-1-2-24 scan > out.ogg``
+    unoptar 0-65-93-24-3-1-2-24 scan > out.ogg
 
 Then play out.ogg with mplayer. You should get first about 41 seconds from the
 Ogg Vorbis file.
 
-*) In the scanner I tried (Canoscan), the lid didn't seem to be heavy enough to
+˚ In the scanner I tried (Canoscan), the lid didn't seem to be heavy enough to
 press the paper down completely - there were blurry spots in the picture.
 Without yellow pages I got 526 reparable bad bits bad from 3.2 million. With
 yellow pages the blurry spots were much sharper and I got only 261 reparably
 bad bits!
 
 Please note the data are padded with zeroes so the original information
-about file length is lost. If your data format doesn't like this then first
+about file length is lost. **If your data format doesn't like this then first
-pack your data with tar.
+pack your data with `tar`.**
 
 A4 <-> US Letter
 ----------------
@@ -112,11 +145,13 @@ Future improvement
 Authorship and Licensing
 ------------------------
 
-© GPL 2007 Karel 'Clock' Kulhavy of Twibright Labs. See COPYING for the text of the GPL license.
+© GPL 2007 Karel 'Clock' Kulhavy of Twibright Labs. 
+
+See COPYING for the text of the GPL license.
 
 e-mail: clock (at) twibright (dot) com
 
 Twibright Optar homepage: http://ronja.twibright.com/optar/
 
-**Special note:** The repository of optar at http://github.com/colindean/optar exists because I
+Improvements © 2012-2018 Colin Dean
-(@colindean) had difficulties finding the source and it seemed to be abandoned/dormant. 
+