Similar question asked here (but no comments allowed!)
I'm opening pdfs and want to save them as jpg, either Cmd-S or File>Export and the default is 72 pixels/inch which loses a lot. Can this default be set to something higher by default.
And the OP wanted to know why it wasn't full res by default. That makes sense.
I don't remember this in Catalina. I looked at Preferences and nothing there. Guess it's time to file a bug report.
I don't believe a pdf document has a dpi. My understanding is the images contained inside the document do, but the document as a whole does not.
When open, the document is rendered at screen resolution for display - 72 dpi. This not having a native dpi allows the screen display size to be scaled.
If you open a pdf document in Adobe Acrobat Pro DC that contains only a 360 dpi jpeg image, the document has no native dpi, but if you click on the image in the document to select it, and then right click on the selected document and from the drop down menu choose Save Image As . . . you can export the image at its native 360 dpi to jpeg.
I could not find an equivalent feature in Preview.
MtD
I don't believe a pdf document has a dpi. My understanding is the images contained inside the document do, but the document as a whole does not.
When open, the document is rendered at screen resolution for display - 72 dpi. This not having a native dpi allows the screen display size to be scaled.
If you open a pdf document in Adobe Acrobat Pro DC that contains only a 360 dpi jpeg image, the document has no native dpi, but if you click on the image in the document to select it, and then right click on the selected document and from the drop down menu choose Save Image As . . . you can export the image at its native 360 dpi to jpeg.
I could not find an equivalent feature in Preview.
MtD
A partial workaround using Keyboard Maestro https://forum.keyboardmaestro.com/t/change-a-setting-in-preview-save-dialog/22442
@Keith. You're right of course, but tell Apple (probably Adobe too) that. The only info given on save is:
No size.
Also my whole process is convoluted. It's a library website with scanned documents. To save the image, I click on Print which brings up a window which I then right click on to open in Preview. Preview (Big Sur) seems to default to the last setting I used, so it can come as a pdf or jpg. I want it as a jpg, so when I go save I get the dialog box above.
PS: With KM forum help, I've got a 9-step macro to automate the process.
It wants you to set that so that it displays/prints properly for documents. You need to tell it what you scanned at so it can print at the correct size. Since it knows the number of pixels, once you set the dpi it can calculate the size of the image.
What counts is the final image size in pixels. dpi is irrelevant.
I didn't scan it. Preview doesn't show the size either in print size or number of pixels.
Preview default resolution jpg is 72 ppi in Big Sur
