Gimp not retaining dimensions at which a file was saved

[Muzician]

I bring up a .jpg image, scale it to particular dimensions - in this case 2600 x 3700 px i.e. 9x12 inches @300 dpi and "Export" as .pdf

Once I export it to .pdf at those dimensions shouldn't it retain them? When I bring it up again the preview shows it as 900 x 1200 px 9x12 inches - when the import dialogue box comes up the scale usually shows it as 900x1200 px  9x12 inches. Even if I use the "scale" function again, it does this. 

I might make additional changes and use overwrite - shouldn't that still retain the same dimensions? When I then go to exit the file it always asks if I want to save changes - I assume this is a redundant query because I've already either exported as or used the overwrite function. 

Am I not doing something right?

[Ofnuts]

When you import a PDF the print definition is always 100PPI by default, you have to force it to 300PPI in the import dialogue to get you image at its initial size.

This said you have no control on the compression level in the PDF so exporting to PDF and re-importing will not yield the exact same image. PDF is a publishing format not a storage format(*). If you want to continue editing your image, save it as a plain image (ideally XCF, but TIFF (without JPG compression) can also do).

(*) When you use Word/LIbreOffice, to you edit the PDF or do you go back to the .DOC?

[Muzician]

(03-11-2022, 10:42 PM)Ofnuts Wrote: When you import a PDF the print definition is always 100PPI by default, you have to force it to 300PPI in the import dialogue to get you image at its initial size.

This said you have no control on the compression level in the PDF so exporting to PDF and re-importing will not yield the exact same image. PDF is a publishing format not a storage format(*). If you want to continue editing your image, save it as a plain image (ideally XCF, but TIFF (without JPG compression) can also do).

(*) When you use Word/LIbreOffice, to you edit the PDF or do you go back to the .DOC?

Thanks for the info! 

No .DOC involved. These are all scanned image files originally scanned as .jpg - any text is just part of the image. I've been going to .pdf because I've been told by a print house they need .pdf.

So you recommend saving to .xcf and make converting to .pdf the last step?

[Ofnuts]

(03-11-2022, 11:35 PM)(soMuzician Wrote:

(03-11-2022, 10:42 PM)Ofnuts Wrote: When you import a PDF the print definition is always 100PPI by default, you have to force it to 300PPI in the import dialogue to get you image at its initial size.

This said you have no control on the compression level in the PDF so exporting to PDF and re-importing will not yield the exact same image. PDF is a publishing format not a storage format(*). If you want to continue editing your image, save it as a plain image (ideally XCF, but TIFF (without JPG compression) can also do).

(*) When you use Word/LIbreOffice, to you edit the PDF or do you go back to the .DOC?

Thanks for the info! 

No .DOC involved. These are all scanned image files originally scanned as .jpg - any text is just part of the image. I've been going to .pdf because I've been told by a print house they need .pdf.

So you recommend saving to .xcf and make converting to .pdf the last step?

Yes, only convert the final version to PDF (so in practice you make PDF "copies" and always keep the original in editable format).