macOS: lossless PNG to PDF conversion I have several pages imported from scanner in PNG format. I use image editor to clean some noise, downscale to 100PDI, convert image palette to grayscale, etc. Finally I've got a bunch of PNG images of small size, looking good at computer screen still.

Then I need to save these PNG pages to a single PDF file for distribution. Earlier I was able to achieve this using Preview.app. However in macOS X High Sierra 10.13 this approach does not work any longer because Preview.app is trying to downscale PNG images by 30% to fit page size. After this transform the image is not sharp enough any longer.

In earlier versions of macOS X Preview.app generated PDF file without transforming the images.

Is there a way to make a PDF file from a set of PNG images using these images as-is (without any transformation)?
ImageMagic

You can use ImageMagick to convert your PNG images to PDFs.

convert -density 100 sample.png sample.pdf


See How can I convert a PNG to a PDF in high quality so it's not blurry or fuzzy? for a related question and answers over on the Unix &amp; Linux site.

Installing ImageMagick and convert

To install the free and open source ImageMagick, and the included convert tool, you can use the Homebrew project.

Once brew is installed, use the following command to install ImageMagick:

brew install imagemagick


Online Services

Alternatively, you can use a web service to perform the conversion for you. Search for convert png to pdf to find such services:


http://png2pdf.com
https://www.zamzar.com/convert/png-to-pdf
https://cloudconvert.com/png-to-pdf