How to convert images to PDF with paper and image size, without ImageMagick

This blog post was published 7 years ago and may or may not have aged well. While reading please keep in mind that it may no longer be accurate or even relevant.

ImageMagick’s convert tool is handy for converting a series of images into a PDF. Just for future reference, here is one method how you can achieve the same without convert. It is useful if you have 1-bit PBM images (e.g. scanned text) at hand:

cat *.pbm | pnmtops -setpage -width 6 -height 8 -imagewidth 3 - | ps2pdf -dEPSFitPage - > book.pdf

This command concatenates all .pbm files, pipes the data to pnmtops to create an intermediary PostScript file on-the-fly, and pipes this PostScript file to ps2pdf to create the final pdf.

With the -width and -height parameter you specify the paper size of the generated PDF in inches, which should correspond to the paper size of the original book. With the -imagewidth parameter you specify the width that your scan/photo takes up on the page.

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