Black lines around picturers after pdf export

[Guest]

Hi, 
I'm making a yearbook and I am doing this in my free time, so I am nowhere near professional levels at InDesign. So I got a question. Our yearbook is almost done and we exported it yesterday. We noticed some black lines around some pictures in our book. How can I fix these?
Thank you for you help.

[Dave Creamer of IDEAS]

Check to see if an object style is applied by selecting an mage and checking the Object Styles panel; if so, remove the stroke setting.

[Guest]

Thanks for your reply. There are no object style applies. The black lines only appear in the pdf and not in the .indd file itself. That's why I'm a puzzled haha

[Dave Creamer of IDEAS]

There are always default Object Styles. The rectangular frame tool automatically has a black border whereas the rectangular graphic frame tool does not. The default black border is very hard to see when the frame edges are on.

[Dave Creamer of IDEAS]

Check the stroke settings too on the object too.

[Guest]

If I checked correctly, really sorry if I did not, none are applied.

[Dave Creamer of IDEAS]

You checked correctly--just double checking. Can you check the Effects panel too? Be sure to select the Object, Fill, and Stroke sub-settings too.

[Dave Creamer of IDEAS]

More questions--how are you achieving transpareny on the images and what are your PDF output settings? It could be "atomic regions" during the flattening in the PDF. 

[Guest]

This is the effect panel. It does say line and filling 100%, but I don't really understand these, because there are no lines and filling applied.

This is where I changed the transparany of the picture.

I got preset pdf settings from the printing company. I don't really understand all the settings and my program is in Dutch, so I doubt I screenshotted the right information. But I really do appreciate you taking the time

[Dave Creamer of IDEAS]

Sorry--I can't read the screen shot. It is possible to put the offending page and the PDF settings in the Creative Cloud folder and share the link?

[Guest]

https://drive.google.com/open?id=1e7NAGGgaB_uMdZXsLcUy1ISsADx7sEcd
I hope a drive link is also fine

[rob day]

They are stitching artifacts from transparency flattening—you used Acrobat 4 Compatability.

If the final output is to a high resolution printer they won’t print. They will display on a relatively low resolution screens when

there is anti-aliasing used, and might print from a low resolution composite printer.

[Dave Creamer of IDEAS]

Thanks. The PDF settings are definitely flattening the image. 

Can you upload the graphics for the first page?

(I'm stepping out for a couple of hours, so if someone else doesn't answer this first, I'll look at it later today.)

[rob day]

You can turn off the anti-aliasing that causes the stitching borders to display via Acrobat‘s Preferences>Page Display by unchecking Smooth Line Art

[rob day]

In Acrobat uncheck Smooth Line Art in Prefs>Page Display, that should prevent the flattened areas from anti-aliasing on screen.

[rob day]

Try unchecking Smooth Line Art in Acrobat’s Page Display Preference, that should prevent the flattened areas from anti-aliasing on screen.

[Guest]

Where can I find this in InDesign 2018?

[Dave Creamer of IDEAS]

That setting is in Acrobat. You might be able to avoid problem by using clipping paths on the art rather than a transparent background. If you upload a sample Photoshop file, I'll take a look at it.

[nigelfrench]

As rob-day pointed out, the stitching line are caused by your PDF export settings. If you have the option to use the Press Ready PDF export setting (which doesn't require flattening) rather PDFx1a, that should solve the problem. At least it worked for me.

[Dave Creamer of IDEAS]

Unfortunately, the printer-supplied joboptions were set to Acrobat 4/PDF 1/3, so I don't think they would accept the PDF. 

[rob day]

Where can I find this in InDesign 2018?

In case my post wasn’t clear the lines are an Acrobat display artifact, they won’t print as long as the output is from Acrobat to a high resolution printer (i.e., any offset press). Acrobat’s Page Display Preferences let you choose how a high resolution print PDF will display on a low resolution screen—print resolution is typically 2400dpi or more, while screen resolutions are typically 100-300ppi.

When you flatten transparency (PDF/X-1a) the page is sliced into sections, and the Acrobat display might anti-alias the section edges depending on your preference. With high resolution print output there is no need for anti-aliasing, so the lines will not print.

In any case you should still get a contract print proof before going to press.