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Layer/Image scaling quality AP vs PS


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Hi, just noticed this.

Trying to run through an old job done in PS using AP instead. I'm trying to gauge how quickly I can work in AP in comparison to PS.

I've attached two images. Both attachments have a sun flare image set to screen mode (or add in 32 bit, tried both). This sun glare texture has been scaled up, both in PS and AP the same %. There are no smart objects used in the PS version.

As you can see, the quality of the image is a lot worse in AP than it is in PS, very pixelated, yet they have both been scaled identically the same amount. Am I missing something? We cannot switch to AP if this is the result, we'd be stepping backwards.

Any ideas? Image quality is set to best in performance.

Edit: it appears the images are scaled differently in the example below, this is just because of zoom extents in PS and AP and how it positioned when i took the screen shot. Also I would of course expect some pixelation blowing up an image like this, but the difference between programs is pretty stark.

Thanks

PS.PNG

AF.PNG

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Hi @MancDan ,

Whtch resample method have you used? 

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I suggest you either resize it using Document > Resize document, or export using one of the "smooth" algorithms, like Lanczos or Bicubic. If you just preview it in the working area, that will be treated as either Bilinear or Nearest Neighbor and does not reflect the actual exported file, unless you use the same algorithm to export as you use for preview. 

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27 minutes ago, GabrielM said:

I suggest you either resize it using Document > Resize document, or export using one of the "smooth" algorithms, like Lanczos or Bicubic. If you just preview it in the working area, that will be treated as either Bilinear or Nearest Neighbor and does not reflect the actual exported file, unless you use the same algorithm to export as you use for preview. 

There is no difference exporting with either of those algorithms, it still saves out pixelated.

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Yes I made it pretty clear it was scaled up quite a lot, its a pretty extreme example and pixelation is expected. The point is, I don't have the pixelation issue with PS and I wondered why. Thanks for your answer though.

So,  were putting it down to how PS and AP re-sample imagery. Got it.

My worry is, using less extreme scaling examples, will such a gap in quality be noticeable too.

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Did some testing, and in other applications scaling up with Bicubic Spline results in an even nicer/usable scaled up version than your Photoshop version.

Unfortunately, Affinity Photo doesn't give the user a choice in resampling algorithms when upscaling and rasterizing a specific layer.

I then attempted to upscale the original with the Resize Document option, and selected Bicubic as the resampling method. The result leaves a LOT to be desired of compared to any of the other apps I tested in (Krita, PhotoLine, Gimp).

In my opinion, based on my previous experiments with downscaling assets, and now with this particular upscale example, Affinity's resampling code base needs to be looked at again. It is a quite fundamental thing to get right. If other applications have no issues with up- and down-scaling, my only conclusion can be that something is amiss with Affinity's basic approach in resampling. The choices of resample methods in the preferences and document size dialog are fairly limited as well. For downsampling, for example, Lanczos and Bicubic are far from ideal choices, but no alternatives such as CatmulRom or MitchelNetravali are on offer in Photo.

As it stands, Photo is lagging behind all the competition in this area. Let's hope the devs will address this in an upcoming release, because it needs to be.

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17 hours ago, GabrielM said:

Right. You're scaling that image up 6 times, and pixelation is expected. Not much we can do, as it's not a bug. Different software have different algorithms to resample. Below is an example from 

PS: Automatic

smooth2.jpg

And AP: Lanczos 3 Separable

smooth.jpg

 

Also, in your example, have you scaled the image up 6 times, or have you just opened the image up in both PS and AP? If so, they aren't dissimilar initially, you need to scale up both images by the same percentage to notice the issue.

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43 minutes ago, MancDan said:

Also, in your example, have you scaled the image up 6 times, or have you just opened the image up in both PS and AP? If so, they aren't dissimilar initially, you need to scale up both images by the same percentage to notice the issue.

I have resized them to proportionally to 3100px on the long edge. 

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