Noise reduction preview

Why does the noise reduction preview look better in the little preview box than on the actual image? The difference is dramatic sometimes.

I’ve read elsewhere in the forum that noise reduction only really becomes apparent upon export–that cannot be true, can it?

How can I get an accurate preview of denoising?

I see in other threads that a command for “Live Review” used to exist, but it doesn’t seem to be there in PL6 elite.

Yep, that’s true. I personally use “Export to DNG with NR and optical corrections only” then do all other processing on the resultant DNG. You can always delete the DNG later if you wish.

Thanks for the reply.

So you have to export to see if the amount of NR you’ve applied is the amount you want? If that’s true, that is absurd.

That’s a really onerous workflow. Plus it doesn’t allow you to tweak noise reduction once other corrections are applied, corrections that often affect the appearance of noise.

Not exactly.

If Noise Reduction is turned on in the palette, then regardless of the type of NR selected the image viewer shows the effect of HQ noise reduction. The loupe in the palette (it’s too small, yes) can be used to give a live preview of any of the PRIME noise reduction options. But to see the whole image with PRIME/DeepPRIME/XD NR applied, yes you need to export and then view the output file in PhotoLab. If you want to know why, then do an export and see how long it takes. Do you want to wait that long every time you make an adjustment?

Hopefully one day the image viewer will be reworked so that it can show the entire image with PRIME and its variants applied in realtime, slowing down only if a change is made to the noise reduction parameters. I hope that’s possible, but only DxO knows for sure.

I don’t think I’ve come across an example of that. PhotoLab is a parametric editor. As such, you’ll see the effects of most adjustments in the image viewer preview in real time, if you’re zoomed in 75% or more. Even if you have to export to see NR, you can look at the result then go back to the RAW image and tweak whatever you like, in any order you like. I know this isn’t the answer you want, but this is how PhotoLab and its predecessor have worked for at least nine years, if not forever.

I saw that claim once, but have never seen an explanation for it. I’ve used the software since Optics Pro 9 and have never seen such an option. I can say, though, that PRIME has evolved since it was first introduced, becoming more advanced and requiring more processing power.

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That make sense; thanks for the substantive explanation, which, now that I think about it, I should have figured out.

That said, I exported a 46 mp image to a DNG with DeepPrimeXD and it took only about 6 or 7 seconds working on an M1 Max Macbook Pro. I’d wait that long to see my NR preview–imagine an option to do so? A little box to click or button to click that says “Update NR Preview” after making adjustments–almost like a “render now” command in a video editor. A lot faster than exporting and looking at the image. Maybe it’s not possible.

I realize it’s a very different program, and perhaps I am just not adjusting well to a new program, but in Lightroom the NR previews are live. That said, the NR is clearly not as good, or so I believe after a fairly short time working with DxO. I am impressed by the quality of the noise reduction.


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You said it yourself, Lightroom NR (or C1) is simply not in the same ball park as PhotoLab DeepPrime. PhotoLab does apply HQ noise reduction to previews (no matter what NR you choose) so the photographer does have a pretty good idea of how NR is affecting the image.

PhotoLab has become a bit slow with all the local adjustments and healing and colour profiles if one uses a wide set of features. Adding Prime style NR to previews would sink real time use of the sliders once and for all.

I’ve come to enjoy doing a preview export of a set for review in a lightweight full screen image browser (LilyView) for rapid review for colour consistency and anything else I might have missed in PhotoLab.

shown here in PL6

from the manual

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It’s only “PC” version, I guess: “Live Review (PC)” (from the manual, p. 39).

Thanks all.

There is not, nor has there ever been the ability to preview the effects of DeepPRIME or DeepPRIME XD in a full screen preview mode before exporting. The only way to preview the results of either of these NR algorithms is in the small preview window. No other option for previewing these results has ever existed in any Mac or Windows version.


In the meanwhile, I still think the best workaround is to apply optical corrections only and then export to a DNG file, in the same folder, with DeepPRIME (XD) applied.

Then you can work on that and, if you don’t want to keep the DNG long term, copy the adjustments from the DNG back to the original.


The speed that you mention is only possible with a powerful GPU. For many users with a simple video card it will take more than a minute, even if they have an excellent CPU.
That said, the option to select a larger/complete preview might be a good idea.

My thoughts on the preview size being too small.
Not having the most powerful computer and a graphics card (though recognised as useful by Photolab) that isn’t state of the art, exporting a 6400iso image with DeepPrime takes about 20 secs and with DeepPrimeXD 1 minute. A full screen NR render would likely take the majority of that time so I would prefer at least a modest increase in the preview size e.g. making the preview rectangle a square with dimensions equal to the existing preview’s width.

I’m totally fine with only having DeepPrime/DeepPrimeXD only available in the preview window, but the option to have a larger preview area (or a “render full preview in main window before export” option) would be really nice for people with more powerful computers.


Maybe a stupid question, have you tried zooming into the photos to see the change? The preview of some enhancement won’t work before you have zoomed into the photo.

There are a few adjustments that require zooming to 75% or above to see the results. DeepPRIME is not one of them. The results with DeepPRIME or DeepPRIME XD can only be viewed in the small preview window or after export.


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The preview window could be larger but in practice DeepPrime works so well that with a little experience you virtually can dial the amount of noise reduction based on ISO. Obviously everyone has a different opinion of what is “enough” noise reduction but the normal fine tuning dance, trying to balance detail with noise reduction, I would normally do in Capture One is simply not needed with DXO. Strange at first but so easy once you are comfortable with DXO.

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I believed this for a while, but have since discovered that I have to vary the amount to avoid artifacts in some types of content - particularly blue skies, brick walls, and tree branches. I’m not able to predict which images will show artifacts and which won’t.

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