Preview of the filter "Diffuse" is completely different from the final result

[Michail]

Do the following:

1. Create a new 4000x4000px document (the larger the document, the more clearly the error is visible)
2. Place an element or use an existing one.
3. Select the noise filter "Dispersion" "Diffuse" and set a value. The desired effect is visible.
4. Confirm the dialog box.

Result: The final effect is completely different from what the preview showed (depending on the size of the document).

If you use the Live filter instead, everything seems to be fine. But a Live-Filter is also just a preview. At the latest when the Live-Filter layer is rasterized (e.g. when exporting to JPEG), the effect changes completely again.

[walt.farrell]

I'm not sure what a "Dispersion" noise filter is. In the English UI the Noise Filter choices are:

Which one are you trying to use? I think it's probably Diffuse (third one from the top).

I just tried it, and I see what you're describing if I start out viewing the image at less than 100% zoom.

However, if you go to 100% zoom or higher before applying the filter, the preview and result are the same. And I think this is intentional behavior, though I've never tried it with filters; only adjustments.

[Michail]

3 hours ago, walt.farrell said:

... Which one are you trying to use? I think it's probably Diffuse (third one from the top).
I just tried it, and I see what you're describing if I start out viewing the image at less than 100% zoom.
However, if you go to 100% zoom or higher before applying the filter, the preview and result are the same. And I think this is intentional behavior, though I've never tried it with filters; only adjustments.

Yes, the English version is "diffuse" - Pardon! I changed it in the theme and in the post.
I'm just wondering how I can judge a filter effect on the whole image if it only looks realistic in 100% view. Specially in case of large images, one only sees an extremely small image cutout at 1:1.

And not even this view is always reliable:

1. Set the view to 100%.
2. Scale the element.
3. Apply the "Diffuse" filter.

Result: Again, there is a significant difference between the preview and the final result.

[walt.farrell]

4 minutes ago, Michail said:

I'm just wondering how I can judge a filter effect on the whole image if it only looks realistic in 100% view. Specially in case of large images, one only sees an extremely small image cutout at 1:1.

You would need to pan the view across the image, using the scroll bars. And yes, you still see only a small amount at a time if it is a large image.

I'm not sure what you mean by "scale the element" in step 2. If you scale the element you're no longer at 100%, are you? Sorry for not understanding this part of your question. Perhaps a picture of that would help.

[Michail]

24 minutes ago, walt.farrell said:

I'm not sure what you mean by "scale the element" in step 2. If you scale the element you're no longer at 100%, are you?

By "Scale" I mean the resizing of the element to be filtered. The document view remains at 100% (Ctrl+1).

[walt.farrell]

7 minutes ago, Michail said:

By "Scale" I mean the resizing of the element to be filtered. The document view remains at 100% (Ctrl+1).

Thanks.

I do not see an issue. I created a 4000x4000px image as you suggested in the first post, and switched the zoom to 100%.

I then drew a rectangle on the canvas, filled with a color. I then rescaled the rectangle.

I added the Diffuse Noise filter, and when clicking Apply the result matched the previewed version. I think I'll need some screenshots and/or a sample document.

[Michail]

1 hour ago, walt.farrell said:

I do not see an issue. I created a 4000x4000px image as you suggested in the first post, and switched the zoom to 100%.
I then drew a rectangle on the canvas, filled with a color. I then rescaled the rectangle.
I added the Diffuse Noise filter, and when clicking Apply the result matched the previewed version. I think I'll need some screenshots and/or a sample document.

Thanks for trying to reproduce it!

It gets crazier and crazier: If the start object is a vector object (as in your case), the filter behaves as expected at 100% (and only then!). But if you start with a pixel object (e.g. a brushstroke or a picture), the filter will have the described behaviour again after scaling. Can you confirm this?

So the filter is unpredictable and cannot be used in practice - no matter in which view size.

[walt.farrell]

30 minutes ago, Michail said:

But if you start with a pixel object (e.g. a brushstroke or a picture), the filter will have the described behaviour again after scaling. Can you confirm this?

Yes, I can confirm that for a scaled raster object (pixel brush, or rasterized image layer, for example), the preview does not match the final result even if the document is viewed at 100%.

Glad you figured it out.

One of the Serif staff will be along when they get to this bug report, and can analyze it further.

Here's a sample file, and a recipe for Serif: diffuse-noise.afphoto

1. Create a 4000x4000px file with File > New. Zoom to 100% view.
2. Create a pixel layer, and paint a stroke. (Bottom layer in the attached file, with the stroke that looks like a 1.)
3. Select the Move Tool, and click on the paint stroke.
4. Drag a corner of the bounding box to scale the pixel object. (This has been done in the sample file.)
5. Filter > Noise > Diffuse... and then set the Intensity to, e.g., 32. Note the appearance, which for me is something like this:
   
    
6. Click Apply, and note that the result changes.
   For me, it's like this:
   
    
7. If you select the unscaled "2" figure in the other layer, and apply the same filter, the appearance before and after pressing Apply is the same.

[Michail]

9 minutes ago, walt.farrell said:

Yes, I can confirm that for a scaled raster object (pixel brush, or rasterized image layer, for example), the preview does not match the final result even if the document is viewed at 100%.

Thanks!
We'll see what Serif has to say. I hope they can also say something about the behaviour in the other view sizes (see my OP).

[Jowday]

On 4/4/2020 at 7:57 PM, Michail said:

Thanks!
We'll see what Serif has to say. I hope they can also say something about the behaviour in the other view sizes (see my OP).

Let me guess. You have this setting enabled in Preferences - Performance:

Set it to:

This is a disastrous usability issue.

I noticed the same difference when working with the unsharp filter and sharpen techniques. The preview with HIGH is false. I gave up on Photo since then. Use it only for finalizing brush art from Designer. Photo has many cool features implemented but they are NOT glued together by usability or traces of involved professionals. A shame.

Example. Part of car in Rome. SOOC (before): 100% - viewing with Bilinear (best quality) set i prefs:

'

Sharpening preview: 100% - viewing with best quality.

Applied just modest sharpness (many will push it to the limit) - viewing with best quality.

Now setting preferences -> performance to Nearest neighbor and notice a dramatic difference 

Which is what Adobe Photoshop CC 2020, FastPictureView Pro shows at 100%

At least Nearest neighbor is the default setting - but every guy on the planet proud of his machine will set it to best... 

Try selling oversharpened, overcooked photos... you will hit a wall. A thick wall.

[Michail]

33 minutes ago, Jowday said:

Let me guess. You have this setting enabled in Preferences - Performance: ...

Thanks. This is very interesting. Maybe you should post this for Serif in a separate thread - if you haven't done it already.
Yes, I have (of course) set "Best Quality". But with the described phenomenon with the diffuse filter, this option seems to be unrelated.

[Jowday]

1 hour ago, Michail said:

Thanks. This is very interesting. Maybe you should post this for Serif in a separate thread - if you haven't done it already.
Yes, I have (of course) set "Best Quality". But with the described phenomenon with the diffuse filter, this option seems to be unrelated.

I did tell them.

If I apply the Diffuse filter with “best” enabled I get a blurred result. Without I get the actual result when exported displayed so it does make a difference.

[Chris B]

Thanks Michail, this has been logged. 

I tried on macOS and it seems to do another pass and make it look like the preview but Windows does not.