Re: [darktable-dev] Vibrance slider in the Basic adjustments tool
Hi,
1. Vibrance is supposed to be *{ RGB } = Y + saturation * ( { RGB } - Y
)^vibrance*, where Y is the luminance channel from XYZ space, and { RGB
} a pixel vector. This way, you perform both operations at once. Also,
using (R + G + B) / 3 instead of Y is generally not a good idea since it
has no perceptual background (R = G = B values does not equal visual
grey in every RGB space, RGB is just a random vector space until a
proper profile is applied).
2. The basic adjustments module is a double edged sword : yes, it's nice
to have a unified *UI* to quickely set-up pictures, but it's not just an
UI, it's also an image operation that gathers at once several operations
that need to be done at different places of the pixel pipe to get proper
results :
* exposure is a scene-referred operations that needs to be done
preferable before input coulour profile, since input matrices are
optimized approximations for mid-tones and skin-tones, in order to
put the RGB values in this sweet spot before applying the profile
* saturation needs to happen after the input matrice, when the Y
channel is defined (actually, input matrices only profile the
conversion from camera RGB to XYZ),
* contrast needs to happen after any frequency filter.
TL;DR the model/view/controller architecture got violated here.
Cheers,
Aurélien.
Le 10/10/2019 à 21:21, Keresztes Barna a écrit :
> On Thu, Oct 10, 2019 at 8:58 PM parafin > wrote:
>
> Is it any different from velvia iop in darktable?
>
>
> Yes, it affects colors less than Velvia. It doesn't intend to emulate
> film.
> The results of this slider are very similar to the standalone Vibrance
> tool.
> There are some important differences:
> - The formula I use is different. It is run earlier in the pipeline,
> in the RGB color space (Vibrance tool runs on Lab)
> - This slider allows negative vibrance settings (so you can fade the
> colors without totally desaturating them)
> - it's a part of the Basic Adjustments tool, it can be used easily to
> set the color "amplitude" in the image together with the saturation
> slider.
> - It has a larger amplitude, so the results are more visible
> (sometimes the original Vibrance tool is barely perceptible).
>
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Re: [darktable-dev] Vibrance slider in the Basic adjustments tool
On Thu, Oct 10, 2019 at 8:58 PM parafin wrote: > Is it any different from velvia iop in darktable? > Yes, it affects colors less than Velvia. It doesn't intend to emulate film. The results of this slider are very similar to the standalone Vibrance tool. There are some important differences: - The formula I use is different. It is run earlier in the pipeline, in the RGB color space (Vibrance tool runs on Lab) - This slider allows negative vibrance settings (so you can fade the colors without totally desaturating them) - it's a part of the Basic Adjustments tool, it can be used easily to set the color "amplitude" in the image together with the saturation slider. - It has a larger amplitude, so the results are more visible (sometimes the original Vibrance tool is barely perceptible). ___ darktable developer mailing list to unsubscribe send a mail to darktable-dev+unsubscr...@lists.darktable.org
Re: [darktable-dev] Vibrance slider in the Basic adjustments tool
Is it any different from velvia iop in darktable? On Thu, 10 Oct 2019 20:44:25 +0200 Keresztes Barna wrote: > Hi all, > > I'm a happy user of Darktable! One of my favorite tools in the 2.7 branch > is the *Basic Adjustments tool*, where I can find in one place most of the > tools I need to make quick adjustments for my image. > > I would like to add a *vibrance* *slider* to this tool. It affects the > saturation of the more saturated pixels. It can be used to accentuate the > colors without becoming unnatural (as it's often the case of the saturation > tool). It also has negative values, so you can use it to make your colors > fade. > Used together with the saturation slider, you can also work on less > saturated areas of the image. Otherwise it doesn't change a lot the > inderface and it fits well in the Basic Adjustments tool. > > It is similar (and similarly positioned) as the vibrance tools in Lightroom > and Aftershot Pro (ASP) and probably other similar software. Note that it > uses a different algorithm than ASP, it's also different from the Vibrance > tool of DT. > > What do you think about the idea? > > Before pushing it to the main branch, I would like to ask you to test it! > You can find my modifications in my fork on Github: > https://github.com/kbarni/darktable > > What do you think? Do you like the results? > > The OpenCL part is untested (don’t have the hardware), so it needs to be > checked too. > > P.S. This is my first contribution to DarkTable; however I developed > several plugins for Bibble/Aftershot Pro, some of which become part of the > core tools. > > ___ > darktable developer mailing list > to unsubscribe send a mail to darktable-dev+unsubscr...@lists.darktable.org > ___ darktable developer mailing list to unsubscribe send a mail to darktable-dev+unsubscr...@lists.darktable.org
[darktable-dev] Problem exporting image
Hello, I have a problem with my darktable program (version 2.6.1) and I hope you can help me. I edited some pictures of my african vacation with darktable. After editing I export the photos on my computer. This worked very well for 8 images. Unfortunally it doesn´t work for one image. When I try to export the image to my computer darktable shuts down. I have tried everything (different JPEG picture size, JPEG 8 BIT, JPEG 20 bit, send to e-mail) but every time darktable shuts down. I also tried to reset the picture export settings but it doesn´t help. Did you ever hear about this problem? I have a pc with a windows 10 system. Enclosed you can find a screenshot of my editing steps. Maybe it helps you to find the problem. Many thanks and kind regards from Germany, Martin ___ darktable developer mailing list to unsubscribe send a mail to darktable-dev+unsubscr...@lists.darktable.org
