Streaking on imported PDF images into Publisher

[moovme]

Hi, I am having some very annoying horizontal hair line streaking happening on some PDF images I have exported from Sketchup and then placed into a Publsiher document. The appearance of streaking can sometimes go away when opened on certain image viewers or when printed, but this is not the case here. There is no streaking whatsoever on the exported images from Sketchup, all of it happens when brought into Publisher.. and ultimately into whatever gets exported out of Publisher with it.

Does anyone know about this issue and has found a way to resolve this incredibly annoying image streaking?

 

[stokerg]

Hi moovme,

Could you attach a sample PDF that shows the issue?  I take you see the streaking within Publisher on screen, without the need for printing it?

[Paul Mc]

It is probably where two areas of colour join and where each side of the join is separately is anti-aliased. This sometimes causes a tiny bit of the underlying colour or background to leak through as the overlapping gradients do not add up to be a solid opaque colour. Pixel alignment can sometimes fix it. A sample of what you are seeing would help.

[moovme]

Here is the Publisher file with the hairline horizontal streaking happening. Yes, the streaking is apparent on the screen without printing it, but is also visible when printing. My apologies for not including it

2020.09.05_Mills Residence_just images.afpub

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[moovme]

Sure. Here are the original PDF exports from Sketchup, without the streaking occurring in them.

Back persp..pdf Front persp..pdf Back Elev.02.pdf Front Elev.02.pdf

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[Paul Mc]

The afpub file includes embedded images which are constructed from a set of horizontal strips. The streaks appear where the strips touch. This will be due to anti-aliasing of the strip edge on both sides not being completely opaque. I loaded Back persp.pdf into Photoshop and it behaves the same way. It looks like Adobe Reader/Acrobat "knows" about the overlap and probably does a linear transition across the tile edges on the source image before resampling for the view. Photoshop and the Affinity programs don't know that this is how it should look so they use a different anti-aliasing method where the background leaks through the adjacent edges. I would suggest this is a problem in the export rather than a problem in Publisher. If you can export as a regular bitmap then this would go away. As this isn't a vector image there is little benefit in exporting as a PDF.

[Paul Mc]

Just a thought. This banding looks like it has been rasterised for printing. You've not sent this out of Sketchup to a PDF file via print capture have you?

 

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[moovme]

That makes a lot of sense. I tried to export the images from Sketchup as jpegs, and then recompiled the sheet in Publisher as before and everything seems to be fine..

Thanks so much for working through this with me and finding the reason this is occurring. You guys are incredible!