White line issue when exporting PDFs in Affinity Designer

[OSunBoy]

Hey everyone,

For a long time, I've been facing a specific issue when exporting PDFs using Affinity Designer 2. A thin white line, sometimes barely noticeable and other times more visible, appears in my exported document. I’ve noticed this is related to the pixels in my documents: the issue tends to occur when the canvas has fractional pixels. In other words, the canvas sometimes cuts through pixels, and when exporting, the leftover part of these cut pixels turns into a white line. It’s hard to explain, so I’m attaching an image to this post to better illustrate the problem.

The thing is, I don’t know how to fix this. Aligning everything perfectly to the pixel grid in the canvas works, but this isn’t an option for me as I need precision.

Details: I’m exporting using the PDF for print preset. Apologies if my explanation isn’t very clear. English isn’t my native language, and describing this issue in it was quite challenging.

Thanks in advance!

[NotMyFault]

You are right that fractional size or position causes the issue.

2 hours ago, OSunBoy said:

Aligning everything perfectly to the pixel grid in the canvas works, but this isn’t an option for me as I need precision.

What do you mean by this? If you export to raster formats, precision means rounding up document size to multiples of pixels. You can’t have it at the same time - exact physical units like millimeters and having whole pixels. To avoid this thin lines, you must round up or choose dpi settings leading to whole pixels.

[OSunBoy]

23 minutes ago, NotMyFault said:

What do you mean by this? If you export to raster formats, precision means rounding up document size to multiples of pixels. You can’t have it at the same time - exact physical units like millimeters and having whole pixels. To avoid this thin lines, you must round up or choose dpi settings leading to whole pixels.

But I’m not trying to export to a raster format; I’m exporting to a vector format (PDF). The document from which I shared some screenshots comes from another file created by someone else, who exported it as a PDF and didn’t encounter any white lines. I’m using the exact same document, with the same properties, and this issue still occurs. The only real difference is that we’re using different software.

[NotMyFault]

Do you observe the lines while rendering in Designer, or after exporting?
Which view mode do you use in Designer?

[OSunBoy]

15 hours ago, NotMyFault said:

Do you observe the lines while rendering in Designer, or after exporting?
Which view mode do you use in Designer?

 

The last image I attached to the post shows how it appears in Affinity, just like the second one does — no white lines. Sorry for not specifying this in the post. I only see the white lines after exporting. As for your last question, I didn’t quite understand it. Could you clarify it a bit more? Either way, I’m attaching the file where I’m experiencing this issue (it’s just one of many).

Sentimentos Menino 2 (espanhol).afdesign

[NotMyFault]

Affinity allows to specify document size in physical units like point.

When exported to PDF, it always rounds up to multiples of pixels (using document DPI setting).

You must specify whole pixels sizes to avoid.

Otherwise you always get a 1px wide seam line on right or bottom side.

Image in Designer (on iPad)

PDF re-opened in Designer

[NotMyFault]

12 minutes ago, OSunBoy said:

As for your last question, I didn’t quite understand it. Could you clarify it a bit more?

https://affinity.help/designer2/en-US.lproj/pages/GetStarted/view.html

[OSunBoy]

I’m viewing the file in vector mode. I understand what you’re saying, but is the only solution to change the document dimensions to whole pixel multiples? I ask this because, as I mentioned before, this document was created by someone else using a different software, and when they exported it, this issue didn’t occur, even though there are fractional pixels.

[NotMyFault]

This behavior of Affinity apps wrt fractional pixel size has been discussed and criticized by users since day 1. I don’t know any trick or shortcut to avoid.

[OSunBoy]

47 minutes ago, NotMyFault said:

This behavior of Affinity apps wrt fractional pixel size has been discussed and criticized by users since day 1. I don’t know any trick or shortcut to avoid.

Damn, that’s really frustrating. It’s a shame that the developers haven’t addressed this issue yet, even though it’s such a basic feature and has been requested for so long. It’s not like we didn’t pay for the software, after all.