X-Git-Url: http://git.rohieb.name/www-rohieb-name.git/blobdiff_plain/c9d00ab950af3c1b58c4b2a2e313b40d7126c326..6b7a87d79ff7abfe44615e260e008442afc35040:/blag/post/optimizing-xsane-s-scanned-pdfs.mdwn diff --git a/blag/post/optimizing-xsane-s-scanned-pdfs.mdwn b/blag/post/optimizing-xsane-s-scanned-pdfs.mdwn index c9db67b..ccf9b42 100644 --- a/blag/post/optimizing-xsane-s-scanned-pdfs.mdwn +++ b/blag/post/optimizing-xsane-s-scanned-pdfs.mdwn @@ -23,7 +23,7 @@ First (non-optimal) solution -------------- At first, I tried to optimize the PDF using [GhostScript][gs]. I -[[use-ghostscript-to-convert-pdf-files|already wrote]] about how GhostScript’s +[[already wrote|use-ghostscript-to-convert-pdf-files]] about how GhostScript’s `-dPDFSETTINGS` option can be used to minimize PDFs by redering the pictures to a smaller resolution. In fact, there are [multiple rendering modes][gs-ps-pdf] (`screen` for 96 dpi, `ebook` for 150 dpi, `printer` for 300 dpi, @@ -31,6 +31,7 @@ and `prepress` for color-preserving 300 dpi), but they are pre-defined, and for my 200 dpi images, `ebook` was not enough (I would lose resolution), while `printer` was too high and would only enlarge the PDF. +[gs]: http://ghostscript.com "Ghostscript homepage" [gs-ps-pdf]: http://milan.kupcevic.net/ghostscript-ps-pdf/#refs "Ghostscript PDF Reference & Tips" @@ -333,6 +334,13 @@ in X and Y direction, which was the resolution at which the images were scanned: $ convert image*jpg -density 200x200 document.pdf +*Update:* You can also use the [`-page` parameter][page] to set the page size +directly. It takes a multitude of predefined paper formats (see link) and will +do the pixel density calculation for you, as well as adding any neccessary +offset if the image ratio is not quite exact: + + $ convert image*jpg -page A4 document.pdf + With that approach, I could reduce the size of my PDF from 250 MB with losslessly compressed images to 38 MB with DCT compression. @@ -367,5 +375,6 @@ document. [scan-to-pdfa]: http://blog.konradvoelkel.de/2013/03/scan-to-pdfa/ "Konrad Voelkel: Linux, OCR and PDF: Scan to PDF/A" [pdf-stream-objects]: http://blog.didierstevens.com/2008/05/19/pdf-stream-objects/ "Didier Stevens: PDF Stream Objects" [pdf-tools]: http://blog.didierstevens.com/programs/pdf-tools/ "Didier Stevens: PDF Tools" +[page]: http://www.imagemagick.org/script/command-line-options.php#page "ImageMagick: Command-line Options" [[!tag PDF note_to_self howto ImageMagic convert file_formats reference longpost]]