Do you know if darktable has a ligthness control tool?

(Roel) #21

I am fairly confident that ACDSee’s Light EQ does a little more magic. Just using the color zones module doesn’t seem to be doing the trick. I have been playing with darktable and ACDSee in parallel for a moment and I find it rather difficult to get visually identical results.

(Sergei Rybalko) #22

One solution is to make preset with 3-4 exposure modules and predefined luminosity masks for different tone ranges. Applying that preset you can play after with exposures of protected by tone areas. It is bit tricky though


Well, I think it’s completely normal that different software do things a bit different. As I noticed in your shared image, it seems that ACDSee has done a little more than just applying the LightEQ. It has definitely applied some kind of local contrast to the photo (The tone curve is also seem in effect). I am confident you can achieve a very similar result if you do just a little more in the darktable. Specifically try “Equalizer”, “Local Contrast”, “Tone Curve”, or “Shadows & Highlights”. Good luck!

(Roger) #24

Serious congrats to you for been the adventurous and rational soul of the group, giving the “new thing” a chance before arguing. You may or may not agree but firstly you have the openness to understand, to know before discard. (Do you know serous studies show only one in twenty is able to defeat the status quo? Welcome to the club :wink:

I hope to find someone like you in the DT development team and convince him to work in the Exposure Zones, because, as explained before and you had found, there is no way to get such results with DT, at least not in the same frame time, and I do not want to simply copy the ACDSee invention but make something better.

(Christian Kanzian) #25

Well, if you like the halos (tree trunk) on the left example. Anyway, both results are not acceptable for me.

Exposure fusion gives me quite good results for such cases (+ a little shadow&highlights, + lowpass). Lately, I discovered that a second instance of the base curve with exposure fusion is even nicer. Parametric masks might help to limit the effect.

IMGP5290.DNG.xmp (6.0 KB)
IMGP5290.DNG (28.2 MB)

image is CC0 if you like to play. Yes, I know it is an easy example, because of the absence of colors.

(Stefan Schmitz) #26

Do you consider the picture on the left as a perfect example? Then pull the yellow a tad up, saturate the red a bit and work the shadows.

(Thomas) #27

Could you provide an original raw and a “perfect” result under CC0? This way it would be much easier to see what you want and how difficult it is to get a similar result in darktable.

(Roel) #28

My example is by no means perfect! It’s only just that, an example. It was suggested that the effect from ACDSee could be replicated with darktable’s color zones module and select by lightness, which I found very hard to do.

@R_O how would you like to proceed? Do you have the time and means to investigate yourself on how to emulate the effect? Possibly with suggestions from us?

N.B. in my example the tone curve module of ACDSee is active to undo the applied camera curve, make the starting point for both images identical.

(Roger) #29

ACDSee is making tone mapping using the dynamic range available in each zone./division and allows you to adjusts blacks and whites. color zones simply modifies the tone curve with no chroma, without HDR, and poor gamma correction (As well as other tone tools It looses contrast easily and you need additional tools to fix the mess -as the local contrast-, so, Exposures Zones to work will need the exposure/tone management used in the histogram -when you right/left click on- which works better than the rest).

Look, most of the comments in here show no understanding of the technologies involved but bad actinide toward my proposal. This is why I wanted to test the community first. Now I guess Exposure Zones is not for Darktable. What is the purpose if most devoted users would be unable to use it?

Thank you for your time.

(Mica) #30

If another software has the feature you need, then you should use that software.

We absolutely do not need your tests. You are welcome to participate to make our software better, you are welcome to share you knowledge and help us enrich one another, but trying to “test the community,” whatever that may mean, will not get you anywhere.

You’ve failed at a through technical explanation of what “Exposure Zones” even is, so you are correct, it is not for darktable.

(Sergei Rybalko) #31

I understand your proposal in intuitive way. Your Exposures Zones would be nice to have in Darktable. Unfortunately I am not a developer. To be more constructive could you find and provide more technical materials, like links to math behind, research etc. Maybe someone would be challenging enough and fork darktable by adding new Exposure Zone module. And with time it will merge to master branch. As it was with liquify module, if I recall well.

(Christian Kanzian) #32

was added by @Pascal_Obry, who is active since I follow the project back in 2012. There were a few people who chimed in and added new features.

I have spent the time to watch the link videos. Previously, I tested capture one and watched their videos. As the tone curve work in Lab color space, darktable has a L curve since the very beginning I guess.

After all, I really do not know what they do better beside markting.

There has not been posted any before and after example. My internet connection is dam slow on upload and I’ve spent some time to get something up. :disappointed_relieved:

(Aurélien Pierre) #33

It looks like a guided filter used as a luminance mask, then some tone curves magic applied in the mask.

The dehaze module implements guided filters, Heiko Bauke told a few months ago that he planned to implement them as another masking option as well.

Anyway, the result from ACDsee looks pretty much overcooked to me, I don’t know what people have against shadows these days.

(Pascal Obry) #34

@Benja1972, indeed the way to go. You fork dt from GitHub and work on your branch until you are satisfied. Of course you also talk to the developers to ensure you’re moving in the right direction and the integration is ok. At some point, when you fell it is ready for merging you create a pull-request. You’ll also need to stay around to answer questions, change code after reviews, adapt things here and there… Be patient… Then it will get merged.

(Roger) #35

All the magic is in already in DT,
You already have the tool to divide the shadows and you already have the tools to recover the dynamic range and manage the exposure.

Then just provide the interface to apply the adjustment to such division.

The auto button just recovers the light in the darker zones and it is used as a reference, not the final adjustment.

I cam also to comment that it is true that the Lab curve in the Color Zones behaves as Capture One Luma Curve, as a result, both have contrast/gamma correction issues. This makes ACDSee/s Light EQ unique in the world, What I am unable to figure is why it is so hard to understand for most people.

My next proposal is to make a focus zones tool, but this is really a complex concept and I do not think DT has the tools, It would be something totally new, but lest start with the easy things…