InDesign Document Setup and Image Resolution

Adobe Expert

However just to note, the first line in my post was:
"I am creating a standard screen use PDF file in InDesign."

The important bit of information came later—the PDF will not be printed (it's ok to use pixel units), and ideally the image quality needs to work on (any?) iPad.

If that's the case, the simple answer is set the document’s width to the largest iPad‘s pixel width (2732px) and keep the placed images’ Effective res at a minimum of 72ppi. If you want a client on the largest iPad to be able to zoom in on an image and keep a high quality, then the Effective res should be higher than 72ppi. When making that decision, you have to consider PDF's compressed file size vs. the audiences bandwidth.

Brainiac

Yes, it will probably be full screen on iOS. But that doesn't mean it will be usable by a human with ordinary eyesight. They will need to zoom unless it is a very simple page with big elements on it. That same page will be a major annoyance to people on a computer.

Bottom line, if you want to be responsive, use a responsive format. HTML can do a great job of this. Nothing is going to be marvellous without reformatting on screens from a couple of inches to over a yard.

Brainiac

Rob, the document size is always in inches in InDesign, and always in inches in Acrobat: pixel size is useless and confusing when designing InDesign PDFs.

Adobe Expert

Rob, the document size is always in inches in InDesign, and always in inches in Acrobat: pixel size is useless and confusing when designing InDesign PDFs.

iOS and OSX browsers don’t consider the print output dimensions when displaying PDFs. Here Firefox is displaying 37.9 x 28.4 the same as 8.5 x 11, and if I print the larger version from the browser it will simply be fit to the Page Size.

Brainiac

You can't control things. Why would anyone view PDFs full screen on a 32 inch monitor? And someone with a tiny phone will have to zoom in just like all other PDFs.

Those images you are looking at... what are your InDesign screen quality settings? And what are your PDF export settings? And, how do you save it from Photoshop and how to you get it into InDesign?

Adobe Expert

Why would anyone view PDFs full screen on a 32 inch monitor?

If the target audience is using iOS devices, Safari is going to fit the PDF into the available screen space. It doesn‘t matter if the exported width dimension is 11" or 37", the PDF is going to be responsive and dynamically resize when it is viewed in an iOS browser

EoinWinstonAuthor

Known Participant

Any text or lines embedded in the iPad images taken from the EPUB are very badly pixelated when compared to the Photoshop originals which are nice and clear. I know there will be some loss of quality but the results I have been getting are unusable. See below for another example, this time using the iPad template - 1024 x 768 size:

InDesign uses a lower res proxy for placed images and as mentioned above the zoom scale is different between the two apps. To check the relative quality, you need to export to PDF and view the resulting PDF in an iPad browser, because the final view scale is going to affect the appearance quality. An iPad with higher screen resolution like the iPad Pro is going to scale up your PDF in order to fit it on the higher density screen.

Hi Rob,

Thanks for that,

I have set all display performance settings within InDesign to be High-Quality.

When I test the exported PDF on iPad (Standard model) and on a laptop the results are the same poor quality imagery. When I set the view on the laptop to be Actual Size or 100% the imagery is terrible. I do expect some loss of quality when scaling happens on different devices and screen sizes but this is very bad.

Note: the level of pixelation and jagged appearance as seen in the exported PDF is totally consistent with how it looks in InDesign so I don't think it's happening during the export process.

Would you expect a no-layers PSD image (1024 x 768 @ 72ppi) saved out from Photoshop and then placed full-screen into an iPad 1024 x 768 template to be so badly pixelated? Or should it be fairly close to what is seen in Photoshop?

Thanks again,

Eoin

Brainiac

The pixel unit may be convenient, but from the number of questions of people who are completely stuck, deep into a complicated workflow, it isn't easy. This affects both InDesign and (more commonly) Illustrator users who are otherwise quite comfortable with the app.

To make it actually easy, it might work if the NEW and EXPORT functions were linked, and BOTH allowed a resolution, which was preserved. (Of course, override possible after suitable warnings). The NEW function would set a size using the resolution and size in pixels. The resolution value (ppi) might usefully be greyed out if the measurement is not pixels.

BobLevine

Adobe Expert

The only time I use pixels is when I’m targeting a device. I do quite a bit of work using in5 these days which does a fabulous job of exporting HTML for use in things such as tradeshow kiosks. It’s as close to the old DPS stuff as I’ve found.

Beyond that…I wouldn’t even think about, especially for PDF.

Adobe Expert

The only time I use pixels is when I’m targeting a device.

That's what the OP is doing.

Alexandre Becquet

Adobe Expert

Hello, just trying with a PSD file and everything working fine.

Maybe reset the preferences.

R

Randy Hagan

Adobe Expert

My suspicion is that it lies in the PDF export settings you're using.

Default PDF Distiller settings for [Smallest File Size] is 100 ppi for color images. Exporting an Interactive PDF from InDesign automatically uses lossy compression to 72 ppi. If you change those settings to not compress your InDesign output to PDF, I believe you can sidestep your problem and get the results you're looking for.

Good luck,

Randy.

Adobe Expert

Whenever I create a new document at a resolution of 1280x800

InDesign documents and pages have no resolution—a page is a vector object.

There is a static Pixel measurement unit. If you set your rulers to Pixels, 1 pixel equals 1/72". If you change the Pixel ruler units to inches, your 1280px x 800px page will measure as 17.778" x 11.111" (1280/72=17.778).

The ruler units (Pixels, Inches, Millimeters, etc.) have no relationship to the pixel per inch resolution of placed images. Placed image resolution can be anything—the Effective resolution listed in the Links panel is the scaled output resolution, while the Actual resolution is the image’s saved resolution with no scaling.

EoinWinstonAuthor

Known Participant

Hi Rob,

Thanks for that,

You mentioned: "InDesign documents and pages have no resolution"

Here is what I meant by the InDesign document being at 1280 x 800 px dimension:

When creating the new document I meant Width-Height I set in the dialogue window. I presumed that if I placed an image that is 1280 x 800 px in to this document that the image would fill the document without the need to scale. The image places @ 50% scale and when I scale it to fit the document width/height it become blurred/pixelated. Every/Any image I place.

Thanks for the help,

Eoin