Multipage PDF unreadable

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nhb
Posts: 2
Joined: Wed May 06, 2020 4:44 pm

Multipage PDF unreadable

Post by nhb » Wed May 06, 2020 5:14 pm

Hello everyone,

I've run into a curious problem today: When creating a multipage PDF from specific PNG files with XnView MP the resulting PDF would only contain blank pages. I've tried multiple readers, namely Adobe Acrobat Reader DC, Chrome, Edge, Gimp, as well as XnView MP itself. None were able to display it correctly, with Adobe Acrobat returning the error message "Dict-object expected". However, when I tried the same process with XnView Classic it worked fine and the resulting PDF displayed properly.

Since I'm no expert I'm left wondering if I'm simply doing something wrong or if this is a problem with XnView MP. I've uploaded three example PNGs, as well as a corrupt PDF created with MP and a working PDF created with Classic here: https://www.dropbox.com/sh/rghxyrnqbdmt ... mbk4a?dl=0

I'm using XnView MP 0.96.1 and XnView Classic 2.49.2, GhostScript Version 9.52 is also installed. This is all on Windows 10, haven‘t tried any other operating systems yet.

Hopefully one of you has some idea as to what is going on.
Last edited by nhb on Wed May 06, 2020 7:29 pm, edited 1 time in total.

cday
XnThusiast
Posts: 2433
Joined: Sun Apr 29, 2012 9:45 am
Location: Cheltenham, U.K.

Re: Multipage PDF unreadable

Post by cday » Wed May 06, 2020 7:28 pm

The issue seems to arise from the PNGs having 32bit colour depth...

When the colour depth is reduced to 24bit, a valid PDF file is created when tested in XnView MP 0.93.1.

Seemingly a bug, if XnView Classic produces a valid PDF... :?:

nhb
Posts: 2
Joined: Wed May 06, 2020 4:44 pm

Re: Multipage PDF unreadable

Post by nhb » Wed May 06, 2020 8:01 pm

Thanks for your reply!

Just tried your suggestion myself in XnView MP 0.96.1, changing the color depth to 24 bit manually on each PNG and then creating a multipage PDF does the trick. From what I can gather from a quick Google search is that apparently PDF doesn't support 32 bit color depth. So I'm assuming that XnView Classic changes the color depth automatically when creating a multipage PDF but MP doesn't for some reason.

Seems like this has been a known issue for a while now: https://www.xnview.com/mantisbt/view.php?id=1201

Well, for the time being I can just manually change the color depth or use Classic, thanks again for your help!

cday
XnThusiast
Posts: 2433
Joined: Sun Apr 29, 2012 9:45 am
Location: Cheltenham, U.K.

Re: Multipage PDF unreadable

Post by cday » Wed May 06, 2020 8:24 pm

nhb wrote:
Wed May 06, 2020 8:01 pm

... for the time being I can just manually change the color depth or use Classic, thanks again for your help!
If you have a large number of files to convert, you could try using XnConvert (or XnView MP Batch convert) to change the PNG colour depth to 24bit, and then output to PDF if your workflow allows...

I'm assuming that XnView Classic changes the color depth automatically when creating a multipage PDF but MP doesn't for some reason.
Pierre?

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