Relight tool

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Relight tool

Lately Im having a bit of love&hate relationship with LZ. Tho i adore the look i get on my images with little to no effort. I miss some tolls that my other go-to raw editor has (RawTherapee). Mostly lens correction tools.

But lets go back to the title problem - Relight tool. I realy like what this tool does, but I dont know what it actually does. So all of my results are on trial&error basis.

Could anyone explain in more technical terms what do Detalil, Depth and Fuzz sliders do, their technical names that are more in line with other raw editors and how do they influence each other.

From Old Help Page

This has some detail of the relight tool -->


By moving the Detail slider  to the right it gives the image more local contrast.  I find the much more then 2.5 can give the image an HDR type look if you're not careful.  Using the Crisp style is more aggresive use of the Detail slider but cuts the strength in half.  I find the Crisp style useful for some images, with some adjustments.


The Depth slider adjusted to the left seems to affect more of the pixels in an image in a flat look, more liner contrast.  To the right gives a "deep" look, harder contrast.  The deep look to the right can bring of the detail in the background out where the flat look can smooth the background a bit to get closer to a bokeh look.


The Fuzz slider adjusts how “fuzzy” the edges between light and dark areas are.  It really hard to see the affect of the tool unless you go to 100% view, even than it's hard to see depending on the image.  Doug mentions in one of his post that anything above .3 is useless, if I remember correctly.  Doug post goes into much more detail but I can't find it right now, perhaps it was a video tutorial that I'm remembering.


EDIT:  I found Doug's great post on Contrast -->



Well.. the lightzone help

Well.. the lightzone help files dont cover anything. Im more puzzled after reading them than not :)

Dugs post sheda some light on things but not exactly what im searching for...

I Suggest

setting the shadow slider to 1 and highlight slider to 0.  This will allow you to work on the 3 contrast sliders below without affecting the lighting.  In Doug's tutorial he indicates the Fuzz slider is directly affected by the detail slider, so you may want to experiment with those two together.  Doug also indicates that setting the detail slider to 0 will keep the contrast as is.  I've actually set the detail slider to 0 and watch the contrast decrease with less noise.  Remember that Polarizer and Tone Mapper have some relationship to what the Relight tool does but with different results.  Other than that I don't know what to tell you unless you can be more specific in what you are looking for.


Hope this helps!



I figured highlights and

I figured highlights and shadow sliders by myself. Those are easy and quite a bit self explanatory :)

What bugs me is the other 3 sliders as their nomenclature is quite different than in the rest of raw editors.

Im interested what do they actually do. Example - in the post above youve said that detail slider affects contrast - in what way? Is it local contrast? Global contrast? Does it appky some kind of tone mapping. That sort of things. Would like what those slidrs do in more technical terms not only - it "increases detail" as written in help files. That doesnt help me one bit :)

And in what way sliders affect each other ie. If i decrease A, what happens to B and vice versa....

Part 4 Relight Tool

The detail slider of the relight tool does local contrast.  Here is part 4 of the 5 part series that Tex Andrews did on the relight tool:



I'm reading source code for

I'm reading source code for Relight tool, but I don't understand it enough. I'm not familiar with tone mapping algorithms.

  • com.lightcrafts.model.ImageEditor.HDROperationV3 (private class ToneMaperTransform)
  • com.lightcrafts.jai.opimage.HDROpImage2#blendloop


The first code generates bilateral-filtered image and Gaussian blurred image from original, and passes it to the second code to calculate "mask" value that is used to adjust local contrast, if my understanding is correct. Yes, some kind of logarithmic tone mapping is done in the second code. (See commented-out lines 163-171 in the second code.)


Since the algorithm is not well explained by original authors from LightCrafts, all we can do is to read the code if we really want to understand what is done under the hood.



Cool, tnx :)

Cool, tnx :)

Maybe some brave soul will fight the code and figure out what each slider actually does.

Trial&error till then :)

Don't confuse Relight with Polarizer

The Relight and Polarizer tools look very similar, but behave differently. You might find this posting of mine to be helpful:

This is another posting from the days when we didn't yet have source code available. It was based on observing the effects of the controls.

Tnx. Helpful reading :)

Tnx. Helpful reading :)

I see you too are puzzled to why the original developers didnt care to explain those tools in more detail :)

All we can do,

to improve the development and help the developers, is to learn, how to read the code, if we really want to understand what is done under the hood. ("It's never easy," the captain of Andromeda used to say.)

So one more question guys,

So one more question guys, for wrapping this thread up - what are the most useful value for Detail, Depth and Fuzz sliders. Ones you use for the most day to day shots (both daytime and nighttime). I ussually slap:

Detail 2,5

Depth 55

Fuzz 0,2

My "Relight moderate" style

Shadows 1,95
Highlights 0,10
Detail 1,60
Depth 64
Fuzz 0,20

I'll chime in here just to say....

that this tool dates back to the heyday of the commercial version, and was at the time a "prize" piece of the software, and thus very proprietary and somewhat secret.  And I think that's why the help files (which are legacy and have not been re-written) don't explain much about this tool.

Without getting too involved in the history, here, it was shortly after this that the Lightcrafts company changed a lot of its internal structure and lost focus on LightZone as it began to develop another app.  This also contributes to the murkiness here.

Yep, too bad they didnt

Yep, too bad they didnt release their development documentation along with the software. That could have speeded some things up :)