Denoise/cleanup

[Irafink]

I'm a total novice to editing, so everything is new...

As a first lesson, I want to clean up this shot, in particular de-noising the sky.  Is there a tutorial that will help me?

Ira

[RichardMH]

You don't really need a tutorial. Try the Noise Reduction Live Filter and a Hue Range Mask. Might not need the mask.

 

[NotMyFault]

Interestingly - on iPad the noise reduction filter shows almost no effect on the sky.

[NotMyFault]

48 minutes ago, RichardMH said:

You don't really need a tutorial.

I don’t know why the denoise filter gives almost no effect on iPad - even when inspecting at 100% or 200% zoom level, and using extreme settings (or any value between 0 and 100% for all the sliders like luminosity, color, contribution).

So the question about getting a tutorial is valid.

For this image, the following workflow gives good results:

• open image
• merge visible to get a pixel layer and copy of layer
• frequency separation with Gaussian blur and a large radius - so that the sky gets smooth.
• add a selection with selection brush covering the sky
• invert selection
• add mask and nest to high frequency layer

This gives a butter-smooth sky, and preserves all details of the rocks where noise is barely noticeable.

[Irafink]

@NotMyFault Thanks!

I'll give this a try!

[Dan C]

On 2/28/2023 at 10:27 PM, NotMyFault said:

I don’t know why the denoise filter gives almost no effect on iPad - even when inspecting at 100% or 200% zoom level, and using extreme settings (or any value between 0 and 100% for all the sliders like luminosity, color, contribution).

I believe I understand the reason for the difference - In RichardMH's screenshot, I can see the image size is 1254 x 1500px, which is the size of the thumbnail for the uploaded image above.

However, when downloading the full resolution image (7869 x 9414px) - I see the same result are yourself both on Windows and iPad, whereby the Denoise does not produce as good as a result when compared to the smaller size image.

I'm not 100% certain of expected behaviours with Denoise on larger vs smaller copies of the same image, so I'm checking with our team regarding this and will log a bug as required

[NotMyFault]

1 hour ago, Dan C said:

I believe I understand the reason for the difference - In RichardMH's screenshot, I can see the image size is 1254 x 1500px, which is the size of the thumbnail for the uploaded image above.

However, when downloading the full resolution image (7869 x 9414px) - I see the same result are yourself both on Windows and iPad, whereby the Denoise does not produce as good as a result when compared to the smaller size image.

I'm not 100% certain of expected behaviours with Denoise on larger vs smaller copies of the same image, so I'm checking with our team regarding this and will log a bug as required

I came to identical conclusions. The image shows severe jpeg compression artefact in the sky, which seem simply far too large for being considered as noise. I didn't spot this on the small iPad screen, but it became obvious on my 34" Display on Mac. The lower resolution screenshots scale down these artefacts to a size which could be interpreted as noise. 

I think the image is a good example to show the limits. If you have 8x8px dark patterns caused by compression artefacts, they can look like noise when zoomed out to 25%, but the denies filter correctly says "this isn't real noise".

[Dan C]

39 minutes ago, NotMyFault said:

I think the image is a good example to show the limits. If you have 8x8px dark patterns caused by compression artefacts, they can look like noise when zoomed out to 25%, but the denies filter correctly says "this isn't real noise".

I don't disagree, however I tested the same full res image in Photo v1.6.5 using the 'extreme' option in the Denoise filter, and as can be seen from the below results this is much closer to my expectations for the tool -

Therefore I'm logging this image with the devs to see if we can improve the functionality of the Denoise filters

[Irafink]

@NotMyFaultI'm still playing with this, and I have a couple questions.

1. Can you please show me the layer stack you used for your edit?

2. Can you show me where you drew the select mask?  I have not yet succeeded in getting a crisp edge around the rock.

Thanks,

[NotMyFault]

Sure. Here are some screenshots of the edit steps. By mistake a made the video with audio of a radio stream and on  Photo beta, so I need to redo it again.

I used bilateral blur instead of Gaussian this time in frequency separation.

 

 

[NotMyFault]

Final result with layers