Differences Between PDF and JPG/PNG Image Format for DPS

When the PDF image format was first made available for DPS articles, the format was limited. Most importantly, interactive overlays were not supported in PDF-based articles, so most designers stuck with the JPG/PNG image format unless they wanted users to be able to pinch & zoom on a page.

With the v18 release of the tools, that changed. Now, all interactive overlays in PDF articles work just as well as they do in JPG/PNG articles.

With the new retina display iPad, using the PDF format has now become the recommended choice for image format. PDF articles are smaller than JPG/PNG articles, and vector content is maintained, resulting in improved scaling. However, there are still some differences between the PDF and JPG/PNG image formats that you should be aware of.

Advantages of PDF

* PDF articles are usually much smaller than JPG/PNG articles, especially long articles.

* Pages in PDF articles can have pinch and zoom enabled.

* All interactive overlays are now supported in PDF.

* The combination of small file size and vector text makes PDF the ideal format for the new retina display iPad.

* With the v26 release, all viewers support the PDF image format, including Android and the Desktop Viewer.

Disadvantages of PDF

* Long Smooth Scrolling articles cannot use the PDF image format. However, starting with v20, Smooth Scrolling articles in which the page height is less than twice the device height can use the PDF image format. In other words, a 1024×1400 article can use the PDF image format, but a 1024×2000 article cannot. Long Smooth Scrolling articles are converted to JPG or PNG.

* There is sometimes a brief load time when flipping to a PDF article.

* In the Folio Producer Editor, preview thumbnails are not available for PDF articles. This shouldn’t be a problem as long as you’re aware of this limitation, but some people look at their PDF folios in the Folio Producer Editor and think their content is missing.

25 Responses to Differences Between PDF and JPG/PNG Image Format for DPS

  1. I mostly use PDF files on printable full-paged documents. As per web usage, PDF files have a bit of lag time and JPEG files look just as good without the hassle.

  2. Greg Pisocky says:

    Bob, do you know if another advanatage might be that the PDF will work with VoiceOver? If the Indesign source was authoried using accessibility enhancements, alternative text on images for example, are those attributes maintained in the resulting PDF for IOS? I can certainly verify myself, just trying to save a little time.

    • Bob Bringhurst says:

      Eventually, yes, that should be an advantage. At this time, text in PDF articles cannot be selected or searched, and accessibility hasn’t been enabled.

  3. using PDF and scrollable frames: after you reach the bottom of a scrollable frame it is not possible to get to the next page (compared to PNG articles)

    also, when viewing in a v18 viewer, you cannot swipe horizontally on a scrollable element to get to the next article.

    —Johannes

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  5. Patrick Gallagher says:

    Bob,

    Is there any reason why our pages don’t show as thumbnails in the Editing mode of Folio Producer online? Articles marked as Advertisements appear fine, but none of our content pages show up with previews? This also seems to sometimes be related to unpublished folios. Any help would be really appreciated.

    -Patrick

    • Bob Bringhurst says:

      Do the articles that aren’t showing up use the PDF image format? If so, that explains it. PDF articles don’t have previews in the Folio Producer Editor.

      • Patrick Gallagher says:

        That absolutely explains it–yes they are in PDF image format. Is that something that is expected to change with future releases? Thanks for your reply and for clarifying.

        • Bob Bringhurst says:

          Yes, the DPS team will likely address this issue since PDF is now the preferred image format for articles.

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  7. Giovana Tarakdjian says:

    Dear,

    realize that the quality of the images contained in the PDF are low.
    What procedure can be done for these images will be high quality?
    Thankfully

  8. Max says:

    Hi Bob,

    is there any possibility to enable the zoom in pdf article?

    kind regards,
    max

    • Bob Bringhurst says:

      I don’t understand the question. You can enable pinch and zoom for PDF articles when you create the viewer app in Viewer Builder.

  9. David says:

    Any idea if the Smooth Scrolling pages will be supported in PDF formats in any future releases. Seems a real shame that such an interesting format for designing in DPS doesn’t allow the text to read crisply.

    Also, if any type of overlay element is added to the page (such as a scrolling frame), does this automatically mean it will end up being saved in a PNG/JPG format?

    Cheers,
    David

    • Bob Bringhurst says:

      PDF is now supported in Smooth Scrolling articles if the article is no longer than 2 page lengths tall. In other words, a 1024×1200 article could be PDF with pinch and zoom but a 1024×1800 article will be converted to JPG or PNG. The plan is to enable PDF pinch and zoom on all Smooth Scrolling articles, but the DPS team hasn’t implemented it yet.

      • David says:

        Ok great, thanks Bob! My original design is much longer than 2x the length so I’ll just await patiently for the team to make that feature happen in future :)

        On a side note, will selecting viewer version 20 or 21 have any impact on whether this would work or not?

  10. articlehack says:

    DPS team will likely address this issue since PDF is now the preferred image format for articles.

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  12. Henry Nolan says:

    Bob, I am having problems. I have created a pdf. format folio but on some of the more interactive articles. They stutter when I try to scroll upwards through the article. Strangely they don’t when I scroll back throughout the article. Any suggestions of what I may be doing wrong?
    Henry

    • Bob Bringhurst says:

      Yes, this is a known issue for some people. This bug will be fixed in the v23 release due in a couple weeks. If you can’t wait until then, one option is to save the folios in v21 format and use Viewer Builder to build a v21 app.

  13. Mark says:

    Hi Bob,

    One of our folio that is based on a PDF that has real delays when loading pages. What is causing this lagginess?

    Thank you,
    Mark

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  15. Paul says:

    Is there a way to change an article to png/jpg that was set up as ‘automatic’ and probably pdf? My preview is only showing in in one of 7 articles and from what I have read, it sounds like they are probably in pdf format.

    I thought I set these all to automatic, and if so, it looks like 6 were created as pdf and only 1 as a png/jpg.

    I’m just starting out and this is a test run. I would like to see all previews for now. So, can I change these 6 articles to png/jpg now that they have defaulted to pdf?

    Thanks – PC

    • Bob Bringhurst says:

      No, you can’t edit the image format of an article. You need to delete the article and create it again with the right image format.