Affinity Immediately Undoes Sharpen Preview

[GaryT]

MacOS 12.3.1, Affinity Photo 1.10.5.

I have a jpeg image I exported from a PDF file.  I want to sharpen the image to enhance the line darkness.  I select "select all" and then Filters > Sharpen >  Unsharp Mask and play with the sliders.  The preview it gives me is perfect.  Exactly what I want.  Unfortunately, when I click "Apply" from the unsharp dialog, the image reverts back to what it had been.  I can only assume there's something about the image format (color depth, mode, etc.) that doesn't allow my changes to stay put.  Any ideas on this?

Thanks.

[John Rostron]

Hello @GaryT, and welcome to the forums.

Are you assessing the sharpness with the zoom level at 100%?

If not, try it at 100%.

John

[NotMyFault]

Can you show us the layer stack? Do you have a pixel layer selected?

[GaryT]

Here is a screen shot of the layer stack.

[RichardMH]

Try the live version of Unsharp Mask (in Live Filters)

[Pšenda]

29 minutes ago, GaryT said:

Here is a screen shot of the layer stack.

Too bad you missed the previous instructions.

5 hours ago, John Rostron said:

Are you assessing the sharpness with the zoom level at 100%?

If not, try it at 100%.

 

[NotMyFault]

8 hours ago, GaryT said:

Here is a screen shot of the layer stack.

Thank you. It differs from the older screenshots in one important detail. Those clearly show the existence of another adjustment layer atop the background.

1. Can you please check, as @Pšenda suggested, that zoom is set to 100% (or 200 or 400, but no other value)?
2. Next, if you use the „destructive“ sharpen filter via menu, check that the background layer was selected in the layer stack
3. or, as @RichardMH suggested, use the live filter variant.
4. another thing to consider: you said you used „select all“. A better way is to use „deselect all“ to ensure no selection is active before choosing a filter from the menu.
5. If you use both Windows and Mac: the ok/cancel buttons are swapped on both platforms for many UI boxes. Drives me crazy.
    

 

[Pšenda]

26 minutes ago, NotMyFault said:

but no other value

... in particular, not less than 100%, otherwise the image is distorted - see the use of the mipmaps method, which Serif uses to speed up the displaying.

[NotMyFault]

1 hour ago, Pšenda said:

... in particular, not less than 100%, otherwise the image is distorted - see the use of the mipmaps method, which Serif uses to speed up the displaying.

I gave 100/200/400 for a reason. 
The image has 1px fine structures. Affinity rendes these fine details wrong in many situations depending on settings (resample method, view quality, exact clipping, OS platform etc) and in case of non-integer multiples of 100%

It is less obvious for landscape/ portraits, but could be a deal breaker for fine details we have in this case.

See below: you get completely wrong colors, even above 100%

Best method to reproduce:

• open file
• set zoom to 100%
• zoom gradually (navigator panel) up to 200%
• then advance to 400% (view quality not „best“, but even then possible)
• you will see lots of red which is not correct.

I crafted this image specifically to make the issue visible. But the same happen with many real-word images.

you can’t work without risk of those effects with pixel art and high contrasting colors except in 400% (and nearest neighbor, best view quality, …), 

 

[Pšenda]

1 hour ago, NotMyFault said:

I gave 100/200/400 for a reason. 

Which, as you've probably noticed, I don't contradict in my comments (see the 3 dots at the beginning of my post, which indicate that my comment only follows yours and complements it). For the OP, however, it may be interesting information that explains why is 100% so essential. Just information "100%" won't tell him "why".

[NotMyFault]

4 minutes ago, Pšenda said:

Which, as you've probably noticed, I don't contradict in my comments (see the 3 dots at the beginning of my post, which indicate that my comment only follows yours and complements it). For the OP, however, it may be interesting information that explains why is 100% so essential. Just information "100%" won't tell him "why".

I interpreted it as contradicting, maybe by mistake. You are welcome 👍🏼

[NotMyFault]

Another observation. The OP screenshot of layers stack shows the histogram, and only very few (7—9) lightness levels (grey color) used.

As these lines are mostly 1px wide it is hard to spot which line has which colors.

To make this better visible, i added a gradient map adjustment and added nodes at the relevant lightness values, and colored them in high contrasting colors. Now you see clearly which lines have which brightness.

When you add an unsharp mask filter, this drastically changes the colors.

If the colors were real (scanned), sharpening will actually wipe out these details. So check wisely before sharpening, or choose sharpening filters like bilateral which maybe preserve colors better  

Of course, the colors maybe non-real by resampling in case zoom levels not 100/200/400 (during scan or later while rescaling or viewing).

[GaryT]

OK, it looks like the answer is that distorted rendering of the "after" image when the zoom factor is less than 100% causes the "issue" I was seeing.  Here is a screen shot of the same image at 100% zoom (and yes, I should have tried that first 😞).  Anyway, I think I understand what it's doing and I can deal with that now that it seems clear what's happening.  Thanks to all for the help, and again, sorry for not having tried the zoom factor first.

 

Gary