Exported image looks different than how the image looks in working file.

[Yonder]

I'm having a problem where what the exported image looks like is not what the image looks like in the working file.

I'm working at a 1:1 pixel scale and need what I'm exporting to be exactly what I'm seeing in the working file. Rasterizing the layer group also makes the image look different from what it looked like pre-rasterize. Attached is a comparison, one being a screenshot of what the image looks like in the working file preview and the other is what the image looks like after being exported as a PNG with Nearest Neighbor resampling. Also attached is a screenshot of my layers.

My view quality in the preferences is also set to Nearest Neighbor.

 

[walt.farrell]

What were the rest of your Export settings?

[Yonder]

Here's the export settings with the preview(though the preview isn't scaled and resampled with nearest neighbor). The export preview shows a different image than how the working file looks.

[Yonder]

Another thing is that this doesn't always happen, I work with a lot of files set up pretty much the same as this one and just export it as a PNG (no scaling) and have no issues with them looking different. This file for some reason isn't doing what I'm expecting it to do.

[walt.farrell]

Thanks. Also, what is the original size of the artwork you're exporting? If you export at the same size as the original there shouldn't be any resampling, as I understand it.

[Yonder]

The original size is 72x96 and that's the size it's being exported at. The problem isn't the resampling, the example I posted is what the image looks like after exporting with no resampling, it was enlarged after being exported. To me, it seems that the noise reduction layer isn't being exported properly.

[NotMyFault]

50 minutes ago, Yonder said:

The original size is 72x96 and that's the size it's being exported at. The problem isn't the resampling, the example I posted is what the image looks like after exporting with no resampling, it was enlarged after being exported. To me, it seems that the noise reduction layer isn't being exported properly.

Can you please test what happens when you “merge visible” as top layer, and export again.

Then compare if this merged layer is identical to the export, or to the rendering below.

To check, use blend mode difference, and add a levels adjustment with white level set to 10%. All black means identical.

my assumption at this stage is that the deviation happens by merging, and not at export.

Next, check for pixels with partial transparency, e.g. using channels panel, or by adding a procedural texture filter with formula 

Sign (1-A) assigned to RGB,

and 1 assigned to A

partial transparent pixels will render white, all others black.

Edited November 6, 2021 by NotMyFault

[Yonder]

Thanks for the tips, here's what I have. I put together a comparison between nearest neighbor and bilinear view quality and resampling at export. Unless otherwise noted, all of these exports were at the original size, 72x96, all that's changed is whether the resampling was bilinear or nearest neighbor.

I've also attached the working file.

SampleFile.afphoto

[NotMyFault]

Thank your for the SampleFile.

I think you can avoid these problems by using "rasterize and trim" earlier in your workflow.

At bottom bottom in the layer stack, there is an 5.PNG image layer, and a 5.PNG pixel layer. If you use transform panel, you can see that there roughly share the same size and position, but if differs from the document size.

I would advise to

• copy one of these layers,
• rasterize & trim.
• This will create a perfectly pixel-aligned layer.
• Then deactivate or delete the unneeded lower layers

This will give you a better bases for the other adjustments put atop these base layers.

What you see are basically artifacts created by the method used for rendering on screen, which actually can produce different results from what you get when using "merge visible" or export (especially when you have layers of non-matching DPI or non-matching alignment of pixel position.

I made several bug reports and raised a feature request to get an accurate preview mode where you can really see who the exported data will look. You may add your vote.

To say it in a different way: Your workflow touches one of the weak spots at Affinity Photo, where Affinity always prioritizes rendering speed over rendering accuracy. It is the currently unavoidable cost of using life filters. You can avoid running into this issue by adjusting your workflow (always rasterize / rasterize & trim for imported images after you have defined the final size and crop region).

Another option to get a accurate preview (of exported result) is to merge visible, and zoom in to 400%

 

[Yonder]

Thank you very much for your help, I'll give your suggestions a try. The only problem, and this will most likely be an ongoing problem unless there's a fix, is that rasterizing the base image layer, that being 5.PNG, changes how the image looks. Certain small details are lost, and at the size I'm working at, those details can make a big difference. But I'm sure I'll be able to find a work around for that and as I said earlier, this doesn't happen with every file like this one.

Thanks again for your help, and I'll definitely give your feature request a vote.