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• • July 15, 2019 at 7:56 pm #117640
    JUNE HE

    Member

    Hi, I have this InDesign issue really bothers me. I don’t know what I did wrong. Appreciate it if you can help me. Thank you so much in advance!
    I created mobile documents in InDesign with height in 1536 px and width in 1152 px.

    I also created JPEG images in Photoshop with the same size (height in 1536 px and width in 1152 px).

    I thought since I created the same height for the image and the document for InDesign, the image should cover the document exactly. However, the result is that the image is way smaller when I insert it into the InDesign file. I have to scale up the image to cover the document page so my effective PPI dropps dramatically. The PPI is reduced from 300 to 71. I would like to know what I did wrong that the image size is so different from the document size. I would like them to be the same size, so the image PPI can remain the same. This document is for a digital book in EPUB format. Thank you so much!

  • July 16, 2019 at 6:34 am #117643
    David Blatner

    Keymaster

    Actually, I think this may just be a misunderstanding. If your image is 1536 px wide, and your document is 1536 px wide, then the image will be the same size as the document at 72 ppi (I’m not sure why it says 71… should be 72)

    That is because InDesign’s pixels are based on 72 ppi.

    • July 16, 2019 at 8:21 am #117644
      JUNE HE

      Member

      Thank you so much David! I used another image with actual 300 PPI to have a try. It scaled down to 156 effective PPI. So I am still in a lost.

  • July 16, 2019 at 8:36 am #117645
    David Blatner

    Keymaster

    What resolution do you need? It is a digital book, right? So you probably do not need more than 150 ppi, unless you expect people to zoom in a lot.

    One way to figure out resolution vs. pixel dimensions is to go to Photoshop and open the New Document dialog box (cmd-N). Then set the measurements to pixels and type in 1152 and 1536 for width and height, and set the resolution to 72. Now change the measurements in the dialog box to Inches, and you can see that it’s a 16 x 21.3 inch document. Big!

    Now, if you want that to be 150 ppi, change the resolution to 150 and then change the measurements back to pixels. The width and height update to 2400 x 3200 px. That is the pixel dimensions for the same size document, but at 150 ppi.

    • July 16, 2019 at 9:33 am #117646
      JUNE HE

      Member

      I tried in Photoshop. It works as you said. The image covers the document exactly. But with InDesign, it’s still the same. Sinde I am making a picture book, 72 PPI seems not a good quality for my purpose.

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