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Noise effect disappears after merge visible


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Problem On a NEF or ORF photo file,  when I apply a Noise effect masq and then I do a Merge Visible, the noise effect disappears.

Also, when applying noise effect within the develop persona module, this effect disappears on Photo Persona module.

How to do to maintain noise effet in order to export in JPEG format  or a print out ?

Thank you.

Affinity 1.8.3 / Mac OS 13.13.6

noise effect.png

Merge visible.png

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There still seems to be noise there but I don’t know what the original image looks like.
I think this might have something to do with your document DPI.
I can’t come up with the words that would explain it properly but if you lower the DPI of a copy of your document and then use Merge Visible you should see what happens.
Maybe someone else can properly explain it.

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Thank you for your reply. But if you can see there is a difference between before and after "Merge visible". The question there, is   how to bypass this change in order tu export a jpeg file WITH the same level of noise ? 

 

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I’ll try and explain this as best I can but I don’t think it will be the whole story, or even totally accurate, just how I understand it to work.

When you apply a Live Noise Filter, the software creates ‘noise pixels’ that are the same size as either the document pixels or the screen pixels, whichever is larger. It probably does this to keep redraw speeds down but there could be other reasons; applying noise to millions of individual pixels on-the-fly is a resource-hungry process.
This means that the noise you see can look different at different zoom levels – you can often see it changing when zooming unless the document pixels are bigger then the screen pixels. The noise you see at low-zoom is an ‘approximation’ of what the noise may look like until you Rasterise.

When you Rasterise the filter the noise is then baked into the layer (image/etc.) at the document DPI rather than the screen DPI. Because of this, the noise may look different when Rasterised. However, if you zoom in before you Rasterise, so you can see individual document pixels, when you do Rasterise the visible noise shouldn’t change.

I hope that has helped to explain it a bit better, but I don’t think there’s anything we can do about it.

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  • 2 months later...

With some operations, like sharpening and noise, you need to examine the preview/result at 100% zoom.  Otherwise, you will get a scaled, likely inaccurate, preview. Also, with images the contain fine detail, like noise, your JPEG export settings should be very high quality (like >90% or so - test the amount of compression you can get away with if file size is an issue).

The attached images depict what the noise looks like in AP before you export and after you export - in the first attachment, the image is scaled to fit the display (about 25% zoom).  In the second attachment, the image is being viewed at 100% zoom.  The two images in each attachment are the preview in AP (left) and the resulting exported JPEG (right).  As you can see, the versions that are not viewed at 100% look very different (as the OP suggests, the noise "disappears") but the images viewed at 100% look very similar.

Kirk

 

 

noisetestscaled.jpg

noiseat100percent.jpg

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If you need your noise to be more noticeable in the final exported JPEG and you plan to resize (i.e., change the number of pixels) the JPEG export for final delivery, then reduce the JPEG in size first to the final output dimensions, and then add the noise.  This way when you view the preview at 100%, you will be able to see the size and quality of the noise that will appear in the JPEG output at final dimensions.

Kirk

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