Affinity Photo loading JPGs with lower quality

[lruggeri]

Hello all,

 

I searched for this topic, but didn't find any answer, so here it goes.

 

I'm editing a small picture just to make the canvas a little bigger andkeeping the actual image the same size.

I created a new document with the dimensions that I wanted, then I loaded the picture to it, centralized and exported as a jpg again with 100% quality.

I noticed the image doesn't stay the same quality as the original. In fact, it's quite worse. I was expecting it to be the same quality, or at least very close.

The exported image is a bit blurry than the original.

Then, as a test, I opened the same file without any change to it, and compared to the original picture using Photos app on windows at roughy the same magnification. It is worse on Affinity, a lot more pixalated. See attached.

What am I doing wrong?

And how can I perform the operation I want keeping highest quality possible. The image is already not good and I can't afford to lose more quality.

 

[GarryP]

Welcome to the forums @lruggeri
One thing you could try, in this particular case, is to use Nearest Neighbour Resampling upon Export, see attached image.
As you can see in my second attached image, there is less blurring than when using Bilinear.
Note: This is not a catch-all ‘fix’ for exporting to JPEG, just an idea for this particular case.

I'm sure the experts will have other ideas for you to try.

[thomaso]

Does your APh screenshot show the exported or the just opened file?
Do you still see a difference if you display the image in APh in 100 % size? (your screenshot says 317,8 %). (Possibly the Photos app of Windows work with different antialising for zoomed images?)

[Old Bruce]

33 minutes ago, lruggeri said:

I'm editing a small picture just to make the canvas a little bigger andkeeping the actual image the same size.

I created a new document with the dimensions that I wanted, then I loaded the picture to it, centralized and exported as a jpg again with 100% quality.

I noticed the image doesn't stay the same quality as the original. In fact, it's quite worse. I was expecting it to be the same quality, or at least very close.

 

The way I would do this is to use the Document > Resize Canvas command (I am assuming you are using Photo) and have the centre anchor chosen.

I think the reason you are seeing a loss of quality is that the image (original jpeg file) is being centred and it. is not on the pixel grid so the jpeg's pixels are being divided in half and this results in a fuzzy image instead of a crisp image.

[lruggeri]

31 minutes ago, GarryP said:

Welcome to the forums @lruggeri
One thing you could try, in this particular case, is to use Nearest Neighbour Resampling upon Export, see attached image.
As you can see in my second attached image, there is less blurring than when using Bilinear.
Note: This is not a catch-all ‘fix’ for exporting to JPEG, just an idea for this particular case.

I'm sure the experts will have other ideas for you to try.

Hello Garry, thanks for the information. Indeed this will be helpful!

But I think the problem lies on loading and/or displaying the image, as it clearly degradates even before exporting.

[GarryP]

Ah.
You could try changing some of the Performance settings in Preferences, there’s one for View Quality for example.
Other than that I’ll leave this to the experts (just thought I might have an easy answer).

[lruggeri]

26 minutes ago, thomaso said:

Does your APh screenshot show the exported or the just opened file?
Do you still see a difference if you display the image in APh in 100 % size? (your screenshot says 317,8 %). (Possibly the Photos app of Windows work with different antialising for zoomed images?)

Hello thomaso! The screenshot is just the opened file. You have an interesting point, maybe Photos app could work differently displaying the picture with a lot of zoom.

But I still think I'm loosing too much quality for this file when exported.

See attached. Both opened with Photos app. Left is original, right is the AP exported file. The only difference between the two is the canvas size, slightly bigger on AP file. Not even a single adjustment.

Exporting using Nearest neighbour makes it very close, which is what I expect.

So, the problem is partially solved, as I got an acceptable image. Still puzzled by the loading mechanism. 😄

 

[lruggeri]

34 minutes ago, Old Bruce said:

The way I would do this is to use the Document > Resize Canvas command (I am assuming you are using Photo) and have the centre anchor chosen.

I think the reason you are seeing a loss of quality is that the image (original jpeg file) is being centred and it. is not on the pixel grid so the jpeg's pixels are being divided in half and this results in a fuzzy image instead of a crisp image.

Thanks Old Bruce! I'll git it a try. I did it this way: I created a new document with the dimensions that I wanted, then I copied the original jpg file to this. So, maybe the quality problem was on the copying process. However, looking at another angle, when I opened the original file and compared to the Photosapp, without any modification at all, I was displaying a lower quality image. Maybe Photos app has a different algorithm to display this when zooming in as pointed out, but I still would expect a better display from a program like Affinity Photo.

[lruggeri]

6 minutes ago, GarryP said:

Ah.
You could try changing some of the Performance settings in Preferences, there’s one for View Quality for example.
Other than that I’ll leave this to the experts (just thought I might have an easy answer).

I'll try that too! Thanks!