Brush Masking Visibility

The brush engine would need to be ripped out and rewritten to use a raster based mask instead of a vector one. It’d be a lot of work AFAIK.

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Hi David,
I am not really answering your question, but I rarely use the brush tool and default to the paths tool most of the time to make a mask that in Lightroom I would have made with the brush tool. If you have already used and appreciate the power of the path tool for mask in DT then just ignore this comment and I apologise for the noise in this thread. If you have never really explored the path tool to draw a mask it is a very powerful way of working.

I do agree David that the brush would be really more useful as a tool if you could see the effect happening instantly and also if the brush could be turnedd into an eraser by using a keyboard shortcut so you could rub out mistakes. But that is a Lightroom approach and it would mean creating a new masking tool and I presume would be a huge amount of work. That is why I prefer the path tool as I can manipulate the path tool after it is drawn if I make mistakes. You can of course still manipulate the brush tools mask as well. So use which ever tool you prefer to use.

Good luck.

So I better understand now why what I asked , really would be impractical to apply.
I agree with Terry that the path tool is the real winner (I also rarely/never use the brush).
The path+parametric control is a real winner.

My reason for picking DT as my #1 editor over excellent free offerings like Rawtherapee or commercial offerings like Lightroom is the exceptional masking options in DT. I have not seen anything that approaches it in other programs. I probably under utilize the brush tool for masks. I also only last week discovered the threshold slider for masks that is so good for sharpening and denoising modules to limit the effect based upon detail and edges.

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Tell me more!! … please


I believe you mentioned it in one of your posts already??


The details threshold slider allows you to select detail to sharpen without bringing up the noise in the skys or smooth surfaces. The mask could be inverted so luma denoising worked in the areas lacking details but doesn’t soften important details.


Oh yes, very useful

It was one of my most wished-for features when I moved over from Lightroom, because I was used to the “masking” option in Lr that works in a similar way. So, when it arrived in darktable I jumped on it in an instant. It’s now part of my basic processing style that I apply to all images, with a detail threshold set at something like +75. That just sharpens most obvious edges but leaves most of the image unsharpened, which I prefer. I can then tweak it to every individual image.

One thing I’ve wondered though is whether feathering should be used with it or not. I find most dt masks need feathering, but not sure about the details threshold ones. Anyone have any thoughts on that?

I come to look at the diffuse or sharpen presets including lens deblur as my go to for sharpening. The module seems to produce a really nice effect without artefacts. The detail threshold slider will be a great addition to my toolkit.


This is something that is probably my fault … there are occasions where I find that the mask is simply not displaying. This could be a conflict by my use of the over/under mask. What I however find frustrating is that once the problem shows-up, I find it hard to solve short of restarting the problem module.
Are others finding the same difficulty?

I implemented that code and would say “normally without feathering”. The mask is calculated a) pixelwise with only the next surrounding locations taken into account and b) use some sigmoid transition so that should be ok/better right as is if you use som blurring / sharpening algo.

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Sorry for asking, but how do you get this details threshold slider? it’s not showing up here.
Screenshot from 2023-03-17 14-02-29

this version 4.2.1 (flatpak linux mint)

What is your darktable version? Looks like it is quite outdated!

I always recommend and use the latest version. On Windows I use 4.3 weekly builds, but since my Windows ccomputer had a cardiac arrest last weekend I am using 4.2 on linux. It looks like you are using an old version that lacks all the latest benefits. I only found out about the threshold slider this week and I am so happy because it really helps with both sharpening and luma denoising.

Are you on a jpg by any chance… you won’t see it in that case… I think both bayer and x-trans have it but maybe not I will have to check…

oh stupid me, I selected a jPEG…

I am surprised this is not an option with JPG. I presume some technical limitation.

I implemented that. No chance for jpegs, xtrans not supported.

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