Grey Outline on Preview Images

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Grey Outline on Preview Images

I have an issue how mojave handles preview images: When I try to preview a .psd-file with a transparency in the background, mojave shows a grey border/shadow around the object. That’s a problem for some apps like sketch. Because when I place an image, the grey outline is still visible. Is there something I can do about this issue? It’s a big problem for me at the moment, because I placed a lot of images with transparency in my sketch-file and the all have an outline now.

I also checked this on other devices (iMac or another Macbook), the problem occurs there, too.

Posted on Apr 17, 2019 3:52 AM

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Answer 1

Apr 17, 2019 4:25 AM in response to nikolaus128

Please explain in detail what your workflow is, and what are the settings for the image file.

Are you converting the image in Preview? Just previewing it does not change the image.

The image I see at the top does not seem to have any transparency at all.

It could be that it is saved in a format that is not fully supported in Preview - or Sketch.

I am not an expert, but matters such as 8-bit vs 16-bit color, or non bitmap layers may be involved here.

Can you post an example psd file showing the problem, to a place like dropbox, so we can test?

Here is a .psd image with transparency, as shown in Preview. Note that the usual checkerboard pattern in transparent areas.

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Answer 2

nikolaus128 Author

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Apr 19, 2019 3:38 AM in response to Luis Sequeira1

Dear Luis Sequeira1,

Sorry for my last answer. I checked again the image settings. You are right! It has indeed to do with the bits per channel. On 16 bit the preview is okay. But it is an issue of Mojave because in Sierra everything is okay.

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Answer 3

nikolaus128 Author

Level 1

8 points

Apr 19, 2019 3:10 AM in response to Luis Sequeira1

Dear Luis Sequeira1,

Thanks for your answer. But maybe we talk about different things.

“The image I see at the top does not seem to have any transparency at all.” Sorry, I don’t know what you mean? The image is just a rectangle in Photoshop on a transparent layer. Do you mean the checkerboard pattern in the background? It’s on another grayscale because I don’t want the hard contrast of the default preference by Photoshop (you can change these settings in the preferences of photoshop).

Let me try to explain again: In Apple Preview transparent pixels within a .psd-file are rendered with a grey outline. It doesn’t seem to happen with .png-files. You can check your own file in the mojave preview. But it seems like that your file doesn’t have transparent pixels because you knocked out the image with a hard selection. Do you know the difference between hard selections and selections with semi-transparent pixels?

It doesn’t have to do with 8 bit or 16 bit... It is a problem of mojave because in Sierra everything is okay. I’ve attached a sierra screenshot as well as the .psd-file. and more detailed screenshots.

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Grey Outline on Preview Images

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