Using darktable's denoise (profiled) on non-raw photo with proper metadata

Hello,

when I use denoise (profiled) on original RAW image, it does an amazing job. However since I do RAW processing in Davinci Resolve, I can’t use this denoiser on original RAW files. Instead, I would like to use darktable’s denoise (profiled) on 16-bit tiff files (output from Resolve). Even though these tiff files include proper metadata (camera manufacturer, camera name and ISO) and denoiser chooses a correct profile, I am having hard time getting good results (images still have chrominance noise present in areas which contain some fine detail). Please is there a way to get better results when applying denoiser on such non-raw images? Thanks.

What settings are you using?

I am using just default settings in denoise (profiled) module.

mode: wavelets
color mode: Y0U0V0
# no curve adjustement
strength: 1
preserver shadows: 1.2
bias correction: 0

In case some example might help I have uploaded both raw and tiff (from Resolve) here:

Here is a zoomed view at denoised raw:

And here is denoised tiff (using the same profile):

When you say “raw denoise” is that the actual Raw Denoise module, or is it the Profiled denoise applied on a raw file vs the tiff from resolve?

Sorry for confusion, it is Profiled denoise applied on a raw file vs tiff from resolve. (I am not using Raw Denoise module.)

Could you go the other way and denoise first in DT and then export into something like an exr and then continue in Davinci…I think it works with exr files and that might work?? Just wondering??

The TIFF is not a raw file, and will break the assumptions behind the profiled denoise. You can still use the module for manual denoising, but that’s it.

Must say I’m curious why you do the initial processing in Davinci Resolve. That strikes me as being a bit backwards.

The reason why I am using Davinci Resolve is due to its color management. Developing RAW files in Resolve using ACES gives me really beautiful color representation - very close to real world. Getting this look using other tools (like darktable / RawTherapee) is usually very hard, if not impossible. Don’t get me wrong, I really like these tools, but I feel like their color pipeline doesn’t come close to what Resolve provides with ACES. Also Resolve’s grading toolset allows for very nice color adjustments (if needed).

Unfortunately Resolve doesn’t have a denoiser that would match the quality of darktable’s profiled denoiser. Therefore I thought it would be great if I could do denoising after I develop my photos in Resolve. (I can’t do it the other way around as I can’t export something like DNG from darktable - meaning I would lose the ACES color pipeline for RAW development.)

Please what assumptions do you mean specifically? I thought Profiled Denoise is working with pixel data (after they have been debayered). Therefore I thought there should be some way to get similar results as I am getting while denoising the RAW file. But maybe I am totally wrong here.

I thought I should start by exporting linear data from Resolve - but it didn’t seem darktable would provide better denoising on those.

Please in case you might have some idea on how to interpret the data from Resolve in order for Profiled Denoiser to work correctly, I would love to hear those. Thanks.

I’m just asking so you can’t color grade an EXR file?? they can be 32bit float… I think its a common exchange for something like blender to davinci… I haven’t tried it I am just asking as it seems like it should be an option or maybe worth trying…

Sure, EXR files are great, but the problem is that once I process RAW file in darktable (lets say into an EXR), I can’t import it into Resolve and get the same look (as I get when I process the RAW file in Resolve). Darktable already does its color management bit - which is what I want to avoid.

I find that hard to believe. Could you share a raw and a Resolve render? Then others could have a try at matching it.

That the data has only been white balanced and demosaiced. I guess you could say that it expects the noise to have a certain “magnitude”, but anything that changes contrast or saturation also changes that “magnitude” and so the result will be wrong.

If you disable color correction and the tone mapper (filmic or sigmoid), then the only color change (apart from color space conversions) is white balance. Can’t you work with that in Resolve?

You can export linear Rec2020 (and no tone mapper, like filmic or sigmoid) into floating-point TIFF. That gives you demosaicked, white-balanced, but otherwise unmodified data.

I don’t really want to make this thread about comparing ACES workflow to other color management approach. I have been a colorist on couple of movies and I am trying to apply the same principles in photography area, that is also why Resolve feels natural for me. It just enables me to get the correct results without spending too much time tweaking the parameters. Each time I have tried jumping into other (photography) tool I felt like I am fighting with the controls.

With that said you can take a look at images attached in the link I posted. Tiff is output from Resolve. I have just tweaked exposure and white balance. Take a look at the candle near bottom of the image. Thanks to ACES ODT to sRGB the bright areas have very nice and natural roll-off. Compare this with RAW opened in darktable with just exposure and white balance tweaked. The candle there has a harsh highlight and oversaturated colors around it.

I see, this makes total sense, thanks.

I can no longer tweak absolute value of white balance and exposure like I could with RAW files. When working with multiple photos, I usually tend to copy these RAW adjustments between images. Since the values are absolute, it works even if image was captured with different white balance or exposure. However once I would work with non-RAW image in Resolve, I would loose this ability. I could then copy only “relative” changes. Such corrections could result in different looks (depending on how camera settings changed between photos). :frowning:

I won’t speak for @Donatzsky, but I’d suspect that the still raw engine in resolve likely doesn’t produce the kind of quality that darktable is capable of, since its a video editor, not a stills editor. Always happy to have my opinion changes :smiley:

Technically there isn’t much of a difference. Resolve does processing of RAW images - whether it is a frame from a video (like ArriRaw from an ARRI camera) or a still image (like cr2 from Canon camera), it doesn’t really matter. But surely there aren’t many still image-related features that darktable provides (like for example the problematic denoising). That is what makes things complicated.

Indeed, can you point us to any documentation about resolves’ raw demoasicing capabilities?

I’m pretty sure it won’t do much if you set all the profiles to the same large linear space. I think you can even use custom profiles so what profile are you first placing your raw in when it opens in DaVinci.
.There are aces colorspace profiles out there… I’m curious as I haven’t used DaVinci for a long time…at one time it was mostly supporting DNG raw and a few select others… has that been extended??

are you applying the color grade in resolve before trying to denoise? If so, you might be skewing the color of your noise and thus darktable would be unable to process it.

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hi, I’d like to ask you about ACES, I’ve made a separate thread here - ACES and De-noise on non-raw photos etc.

To take a totally different approach. Why not forget the denoise profiled module if it doesn’t work correctly with your tiff files. There are other denoising modules in DT that may work well for you. Contrast equalizer, astrophoto denoise, diffuse or sharpen, and surface blur are four modules that come to my mind. I also feel your problem is relevant for people editing non-raw images in DT. This is something I am getting more interested in myself. I have also wondered why DT can not export a DNG . I am no coder so I presume there is a good reason for no DNG offering for exports.