Get one long tiff from a multipage-PDF with these two simple commands

Every once in a while I receive a well log or mud log from a client in multipage-pdf form. In other words, rather than a single, very tall raster image (in tiff format, for example), the image has been cut up into many, say, 8.5x11-inch or A4 pages and saved in pdf format. Instead, I often want a file as a single, long page in tiff format for use in Petra or to send off to a digitizer.

Here’s how I use the wonderful command line program ImageMagick to transform a multipage-pdf into single page tiff. It’s a two step process.

First, after ImageMagick is installed, cd to the directory where the PDF is and issue this command at the terminal:

convert -density 300 MULTIPAGE_PDF.pdf -alpha remove -compress lzw page_%0d.tiff

That command will open the pdf and spit out each page to its own tiff file. Here is what each argument does.

• The image resolution can be controlled with the -density flag, here specified as 300 dpi. The larger the number, the larger the tiff files will be and the longer the command will take to run.
• -alpha with the remove keyword will remove the transparency of the pdf; in some cases it may be necessary to also explicitly specify a background color for the tiff files, for example -background white.
• -compress with the lzw keyword will compress the tiffs.
• Last is the pattern for the name of the output files. The %0d nugget will return two-digit page numbers (e.g. 01, 02, … 98, 99). This ensures that the page order is preserved when the pages are recombined.

The second step is to combine all the tiffs into a single page with this command:

convert -append page_*.tiff SINGLEPAGE_TIFF.tiff

The multipage-pdf has now been transformed into a single-page tiff. Image magic indeed!