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In order to remove some noise in the sky of an image I have nested a noise reduction live filter in its pixel layer.  In this screen shot, the position of the Noise Reduction live filter is clear underneath the Dehazed Background pixel layer, but it has been unchecked to show the luminance noise in the sky.

151870673_NRoffnoisysky.thumb.jpeg.377dcec2bf81abe4b0db78bead6701da.jpeg

After checking it and setting Luminance to 25%, the sky is still splotchy, the noise having been reduced but not completely eliminated:

1522700079_splotchyskydespiteNR.thumb.jpeg.92bab6ce46d1da3d5308750ef277d1f1.jpeg

When, without modifying any settings in the Noise Reduction live filter I move it to the position shown in the following screen shot, the luminance noise disappears:

2058075072_NRlivefilterindifferentpositionclearsky.thumb.jpeg.8f4cf702ae5daa773a1d9805bb478597.jpeg

What is the significance of the "half-child" position in that screen shot?  Why is the live filter in this position so much more effective than as a sibling of the other child layers?

Thanks

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Hi Richard Liu :)

With the adjustment nested to your Pixel layer, it will only apply noise reduction to that image and the other adjustments nested to it.

With it unnested from the Pixel layer and at the bottom of the layers stack, this adjustment is now applied to the whole document, including the pixel layer and it's nested adjustments, and the adjustments above the pixel layer. I can only imagine that another one of your adjustment layers - not nested to the pixel layer - is changing the way the denoise is being calculated across the image, resulting in a different output. I hope this helps!

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Hi @Dan C,

It's very subtle, but the Noise Reduction filter is nested in the last screen shot.  It's just slightly less indented than the other live filter layers.  In the middle screen shot, that is not the case.

In an old tutorial for Affinity Photo 1.6 titled "Clipping vs. Masking," https://player.vimeo.com/video/168186956/, @James Ritson describes a similar situation using a rectangle shape and a JPEG image in a newly created document and nesting the rectangle within the JPEG in the "normal" way (1:36 into the tutorial), i.e., the way all the live filters except the Noise Reduction on in the last screen shot are nested in the Dehazed Background.  He calls this kind of nesting "nesting as a layer mask."  Subsequently, he nests the JPEG in the rectangle (2:19), this time being careful the way he "offers" the former to the latter (2:38), so that it is indented, but not as much as the rectangle was in the JPEG (2:52).  This he calls "nesting as a clipping layer."  Now comes the confusing part, where he shows that adjustment and live filter layers also can be nested in these two ways (4:45), and does that with a White Balance adjustment layer in a JPEG pixel layer, concluding at 6:13, "So, there is no practical difference when you're doing clipping or masking with adjustments and filters [...]"  That seems to contradict what I document in this thread, for which the issue would seem to be less whether I'm doing clipping or masking, than the order in which a mix of children and what I'm calling "half-children" layers applied, indeed, how differently they act on the parent.

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Thanks for that, could you please upload a copy of your .afphoto file so I can investigate this further? The Noise Reduction filter has recently been rewritten and I'm not yet certain if this is an intended or unintended effect following this.

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Thanks for that, I've opened your file and moved the filter between 3 different positions, un-clipped, clipped and clipped & masked.

As you can see in this video, at 100% zoom when the filter is both clipped and clipped & masked the adjustment appears visually the same.

When un-clipping the filter, it's no longer being applied and the noise returns to the sky.

Could you please confirm, did you change the zoom level or any of the Adjustment options when moving the filter around your document?

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On 6/26/2019 at 1:15 AM, Richard Liu said:

What is the significance of the "half-child" position in that screen shot?  Why is the live filter in this position so much more effective than as a sibling of the other child layers?

Thanks

Hi Richard, it is because the noise reduction is at the bottom of the stack, when you release it to the "half child" position you are removing it from the mask and allowing it to work, it will still only work on the parent layer, it is just being overpowered by all of the sharpening methods. If you move it to the top of the stack, but still in the full child position it will work the same way, this is because it is denoising the layers below.

The noise filter is having to work much harder due to the sharpening, that is why you are needing to increase the luminosity slider to clean it up.

The clarity slider is the biggest culprit for increasing the noise, have you tried to invert the clarity adjustment then using a white paintbrush just paint over the areas that need the extra clarity, this will drastically reduce the amount of noise in your sky.

@Dan C The Denoise filter works very well for me.

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@Dan C

Thanks for your time, Dan.

36 minutes ago, Dan C said:

un-clipped, clipped and clipped & masked

I'm not sure I've encountered any formal definition of clipped layer and masked layer, let alone clipped & masked layer.  So, as I understand the terms, both clipped layer and masked layer refer to children, or embedded layers, of (in this case) Dehazed Background.  Masked layers are the normal case.  They occur when I select Dehazed Background then add, say, a live filter layer, or when I, to use @James Ritson's term, offer the layer to Dehazed Background in such a way that a vertical blue bar is displayed.  In contrast, clipped layers result from offering a layer to Dehazed Background so that the long-ish horizontal blue bar appears.  Clipped layers are only slightly indented underneath the parent layer, so slightly in fact, that they could almost be mistaken for non-embedded.

I have prepared a screen video.

By referring to the Navigation panel in the lower right corner, you can confirm that Affinity Photo is displaying at 100%.  I begin by moving the Noise Reduction live filter above the Dehazed Background layer.  Then I vertical-bluebar-offer it to that layer, and subsequently push it down the children stack, on layer at a time, by vertical-blue-bar offering it to the next child below.  You can see the noise gradually increase, the further down the stack I push the filter.  Then I horizontal-blue-bar offer it to Dehazed Background, so that it becomes a clipped layer.  You can see the noise disappear.  Of course, if I moved it further down, so that it became the first layer in the stack and were not embedded in any way in Dehazed Background, it would have no effect at all, having nothing to work on.

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Posted (edited)

@Murfee,

I just read your post after replying to @Dan C.  Thanks very much for your enlightening explanation.  So, to recap,

  1. The children or masked layers are executed bottom up, i. e., last to first, so putting it last executes it before all the sharpening has had a chance to do the damage that I intend it to repair.
  2. Placing it at the top of the masked layers causes it to execute after the other filters, which is what I want.
  3. Making it a clipped layer, i. e., pulling it out to the half-indented position, apparently causes it to be executed after all the masked layers, despite the fact that it is beneath them. 
Quote

The clarity slider is the biggest culprit for increasing the noise, have you tried to invert the clarity adjustment then using a white paintbrush just paint over the areas that need the extra clarity, this will drastically reduce the amount of noise in your sky.

No, I haven't tried that, but I certainly will.  Since the Clarity live filter is rather subtle, it takes a practiced eye to recognize where it is needed and works.  Any alternative would be not to apply it to the sky.

Edited by Richard Liu
Replied to the second part of @Murfee's reply

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2 minutes ago, Richard Liu said:

@Murfee,

I just read your post after replying to @Dan C.  Thanks very much for your enlightening explanation.  So, to recap,

  1. The children or masked layers are executed bottom up, i. e., last to first, so putting it last executes it before all the sharpening has had a chance to do the damage that I intend it to repair.
  2. Placing it at the top of the masked layers causes it to execute after the other filters, which is what I want.
  3. Making it a clipped layer, i. e., pulling it out to the half-indented position, apparently causes it to be executed after all the masked layers, despite the fact that it is beneath them. 

That is pretty much it :) I am not sure about if it executes after all the masked layers, but it means it is not being constrained by the mask ... I have no idea on the technicalities of what is going on... just a fair bit of previous trial & error. :D

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@Murfee,

Following your suggestion I checked which of the three sharpening filters is generating the most luminance noise.  In my case, it's the Unsharp Mask.  So I inverted it and just painted over roughly everything except the sky, then saved the Unsharp Mask's alpha channel as a spare channel, and loaded it to the other two live filters, Clarity and High Pass.  At that point, I really didn't need the Noise Reduction filter anymore, but if I wanted to use it, less than half the previous amount was more than sufficient to reduce the luminance noise that existed before sharpening.

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@Murfee,

Speaking of exports, I've been trying to upload some JPEGs exported from Affinity Photo 1.7.1 to this site and have received the error message, "There was a problem processing the uploaded file. -200"  Do you have any idea what the problem might be?  They're about 25MB each.

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2 minutes ago, Richard Liu said:

"There was a problem processing the uploaded file. -200"  Do you have any idea what the problem might be?  They're about 25MB each.

Error code 200 will occur when an image is too "wide" to upload to the forum. Reducing the width of the image to about 2000px has always worked for me 


Due to the fact that Boris Johnson is now our Prime Minister, punctuation, spelling and grammar will never be worried about ever again.  We now have far bigger problems to be concerned about.

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