Take the 2-minute tour ×
Super User is a question and answer site for computer enthusiasts and power users. It's 100% free, no registration required.

When I try to merge two .pdf files using Imagemagick

convert pdf1.pdf pdf2.pdf temp.pdf

the resulting temp.pdf file seems to have very low resolution. How can I keep the resolution same as in the source files?

share|improve this question
add comment

migrated from stackoverflow.com Oct 11 '09 at 20:50

This question came from our site for professional and enthusiast programmers.

6 Answers

Barns's right, but if pdftk didn't work try ghostscript.

gs -dBATCH -dNOPAUSE -q -sDEVICE=pdfwrite -sOutputFile=temp.pdf pdf1.pdf pdf2.pdf
share|improve this answer
    
Yes. This is perfect for merging pdfs. Just download and install converter.exe from cutepdf.com/products/cutepdf/writer.asp and use your command. Except, for win32, it's gswin32c, if the GPLGS directory in the program files folder is in the path. –  Shadow2531 Feb 8 '10 at 11:38
add comment

Imagemagick's convert command is normally used for converting image files from one format to another, and in this case, it is possible that it is actually performing an internal conversion of sorts before outputting the two "images" (PDFs) into a single file.

I would suggest you consider using the PDF Toolkit (pdftk) instead http://www.accesspdf.com/pdftk/

From the examples on the website, this should be as simple as:

pdftk pdf1.pdf pdf2.pdf cat output temp.pdf
share|improve this answer
    
I'm running on OS X 10.6.1 and I tried to install pdftk via Macports. It seems that pdftk is deprecated on Mac, the installation would not finish. So, I tried to do this using Imagemagick. –  jraja Sep 27 '09 at 13:41
    
On Ubuntu pdftk was no problem to install from apt, and it did the trick gloriously. I've used ImageMagick to stitch together PDFs before with great success, but because it rasterizes PDFs first (understandably--it doesn't work with vectors) it doesn't look so good for most text documents. But pdftk worked great--thanks for the suggestion. –  Iguananaut Mar 3 '13 at 0:40
add comment

If every file you want to merge is in the same folder:

convert -density 150 $(ls -rt *pdf) output.pdf

the argument -density 150 keeps the quality of the merged PDFs.

share|improve this answer
add comment

I always forget how to do this and find this question first when I search.

convert -density 600 file1.pdf file2.pdf -resize 50% new.pdf

The linked example has the density at 144, however, that has never been high enough to not appear pixelated.

http://studio.imagemagick.org/pipermail/magick-users/2009-September/022958.html

share|improve this answer
add comment

If running linux you can also try poppler which provides pdfunite which concatenates without manipulating the resolution.

share|improve this answer
add comment

I couldn't find any way of joining two pdf files together while keeping the resolution good and the text intact, but I figured out a way to convert it into a high resolution png file.

pdftoppm -f 1 -l 1 -aa yes -aaVector yes -png -r 300 page.pdf > tmp1.png
pdftoppm -f 2 -l 2 -aa yes -aaVector yes -png -r 300 page.pdf > tmp2.png
convert tmp1.png tmp2.png +append -quality 100 page.png

This takes to first two pages of page.pdf and joins them into a side by side high resolution png file.

Changing the last line to

convert tmp1.png tmp2.png +append -quality 100 page.pdf

will result in a pdf document output as I later figured out after messing around with pngtopnm, pnmtops, ps2pdf.

share|improve this answer
1  
-1 for suggesting to rasterize a (possible) vector image. That's not the way to go. –  Marco May 10 '12 at 11:59
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.