Retaining quality with PDF

[GoGojira]

Hi all,

I need to produce a professional print quality image in PDF from a gimp project. The problem is Gimp 2.10 seems to be  lowering the quality of the image to about a quarter of the original resolution when I export to PDF, with no visible settings (at least to my eye) to change quality. My "print size" settings are correct, I did check that.

I've added an image of the problem below. Note the resolution of the original project, and the resolution of the PDF file in the info at the left.

So please help me. How can I produce a PDF image and retain the original quality of the image? Any input is greatly appreciated. Thanks in advance.

   

[rich2005]

Gimp by default imports a PDF at 100 pixels-per-inch (ppi) Your image correctly exported @ 300 ppi for the printer. The printer is only interested at the page size as reported by the PDF.

To check the PDF in Gimp set the resolution to 300 ppi in the Import from PDF dialogue.

   

You should check with your printer/publisher for problems at their end

edit: Gimp PDF is essentially a bitmap image wrapped up as a PDF. A better tool for sending to a publisher is Scribus, Image from Gimp, add the text in Scribus if possible. Plenty of info on using Scribus around. (and versions for OSX)

edit again. A closer look at your PDF viewer. It is set to 'Preview' which possibly explains the small size. Encoding cairo 1.16 - my linux is 1.15, should not make any difference although who knows with OSX.

[GoGojira]

Thanks Rich,

This cover is for Amazon books and they demand a PDF--there's no way around it. "Preview" is just the name of the application that opens PDFs on a macbook. The dialogue box you see there is the "info" showing the exact dimensions/data of the PDF file.

Please could you direct me to the "import from PDF" dialogue? I had a look around Gimp and couldn't locate it.

Thanks again.

EDIT: okay. I understand now. Putting the image back in gimp and setting the resolution to 300dpi show that the info's still there, although Preview shows with lower resoultion. That's great! But Amazon is taking the image at 100dpi it seems, because they show me a shrunken version that doesn't fit my book in their print preview. Guess I'll have to haunt the forums over at kdp. Thanks one final time for helping me understand this.

[rich2005]

In case you come back.

From your screenshot: The Resolution in your screenshot is 923 x 606 Divide either into your 3848 x 2775 @300 ppi image size gives a scale factor of 4.169
Divide 300 by 4.169 = 72 This is the original setting for CRT computer monitors. These days it can be much higher, depends on monitor quality.

..."Preview" is just the name of the application that opens PDFs on a macbook... - Could be an issue there, there might be some embedded small image in the download. You can get the same in some image formats.

However, as mentioned before, you should still look at Scribus as the tool for generating the PDF. Amazon from their how-to seem to prefer a PDF x1a format. You can get one of those out of Scibus, but it is a steep learning curve.

   

[GoGojira]

Thanks a lot for this information and your time, Rich. Much appreciated.