tone mapping - before and after

[daveleo]

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Inspired by some other postings here, this will be an open thread for posting "before & after" tone-mapped images, and commentary. Let me suggest that each image poster note what software was used and any important such technical remarks.

Please do not imagine that I personally know what I am doing on this topic; I have tone-mapped about 2 dozen images and am only happy with the results from two of these ! . . . so this is the blind leading the blind, if you will (at least at the moment)

 

Below is a before-after comparison of a bridge in Rome.

Leica D2, postprocessed using the "enhanced tone-map" plugin to the GIMP image editor.

This is a single image . . . not multiple exposures, as in HDR photography.

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[allamande]

Dave,

 

It's a great idea for a thread. I must say you've set the bar too high with that gorgeous opening! I have to do some homework before I dare post. Stay tuned...

 

Ece

[daveleo]

i'll post this one more and then lay low for a while.

again Leica D2. this is a single original image.

 

i also include a screen capture of the setting i used (don't ask me to explain, as i am still not clear on what is being done here by the software) . . .

 

i can say that the effect, if done very moderately, is sometimes an improvement, but the vast majority of the images that i tried are not an improvement.

 

i also think that the same results could be efected by using standard curves, contrast, etc controls, but have not experimented to do this.

 

here is (1)before (2)after (3)settings

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[allamande]

I couldn't resist the urge to put everything aside and quickly work one image (caution: the verb "work" is a massive overstatement here).

 

BTW, the following link has some useful information and examples for doing this with GIMP: Tone Mapping with GIMP

 

Telegraph Hill and Coit Tower, San Francisco, from my hotel room, a couple of weeks ago:

Original:

 

Tone-mapped with GIMP and massaged in LR:

 

 

Despite the noise and the halos, I kind of like this, at least I am beginning to see the potential.

Dave, as you say, certain types of images are better suited for this treatment. The parameter value decisions also make a big difference in what you end up achieving. See blog above.

 

I like your second example.

 

Ece

[pop]

Dave and Ece - I am terribly impressed with your samples. For "historical" reasons I will put one here which both of you have seen already. The first is the downscaled original right out of the LC1. The second one uses the same software as Dave used, with the settings 2-75-90-1.

 

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As you can clearly see, the main effect takes place in the shop window.

[pop]

For my second pair, I chose a picture with fewer variables so as to be able to observe better what's happening.

 

Again, the first one is straight out of the LC1:

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Again, the second one has been processed using the GIMP with the Advanced Tone Mapping script. The settings are 1-75-100-1.

[pop]

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Some factoids.

 

The usual HDR workflow consists of the following steps:

• Acquire several takes of the same scene with markedly different exposures. "Ideally", the brightest bits of one exposure coincide with the darkest bits of the next one.
  
• Combine the different exposures of moderate color depth into one of considerably larger color depth. Your combined picture now contains subtly differentiated shades of color in each part of the image, from brightest to darkest. Unfortunately, you have no means of displaying so many tones.
  
• Enter tone mapping: apply a procedure which reduces the color depth of the whole image in a way which renders recognizable details in every part of the image.
  

 

In this thread, we just exercise the third part of the HDR workflow, namely the tone mapping. We apply the tone mapping to plain pictures taken with just one exposure.

[pop]

I just found an interactive tone mapper. It is said to be available both for Linux and Windows. Since I am too lazy to compile the Linux version, I chickened out. I use the Window version in Linux. I have Crossover installed.

 

The parameters are not quite the same as with the GIMP script (advanced tone mapping, above), but you can experiment to your heart's desire.

 

LDR Tonemapping

 

There's one thing which took me quite a while to get the hang of. When rescaling the picture shown, make sure to move the mouse pointer onto some point well within the actual image before using the mouse wheel to scale it. Using the mouse wheel when within the dark background area of the screen will cause most puzzling behaviour of the image.

[daveleo]

keeping this topic alive . . . below are 3 images . . . a baseline photo, a tone-mapped version and a version modified simply using a "curves" adjustment (all of this was done in the GIMP . . . the tonemap settings are shown in the last screen capture)

 

my opinion is that the tone-mapped version is the most dramatic and the "curves-adjusted" version is the most natural.

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[rickp13]

dave#4, thanks very much for starting this thread, and the same to ece and pop for keeping it going. this is my first 'mapped' photo, so i'm pleased, but i hope you'll find it to be a good starting point.

 

basics:

 

• st. peter ording on the north sea. there's a long boardwalk between the town and the beach across the marshlands to minimize impact on the marsh and wildlife.
  
• the photo was taken using the m9 in bracketing mode (three 1/2 stop steps). 21mm elmarit pre-asph, 1/125 at iso 160.
  
• photoshop cs3 put the three images together using file/scripts/load files into stack
  
• auto level on each of the three layers
  
• filter/smart sharpen at 50 1.3
  
• flatten image
  
• adjust overall brightness
  
• crop to remove the unaligned edges
  
• the comparison image (before) is the lightest of the 3
  

greetings from hamburg

 

rick

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[osscat]

I can not yet properly get my head around this Tone Mapping thing - however I did try to see if the original post would respond well to good old (?) fashioned PP.

 

Here is what I got from it - hope you don't mind 'Daveleo'

 

Can someone explain what advantage is gained from TM?

 

Osscat

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[allamande]

Osscat,

 

That's a nice rendition. I think both Philipp and Dave mentioned at various points that it's possible to work all this in PS. Beyond that, Philipp is the expert to tell you the detail.

 

Here is another example I worked on. One thing I've noticed is that if you run the low strength routine twice, the effect is better controlled (this maybe the placebo effect talking, but it looks that way to me ).

 

before:

 

and gimped:

 

 

I did not apply any other PP to this gimp output. This is an interior view from the California Academy of Sciences building (designed by Renzo Piano), at the Golden Gate Park, San Francisco.

 

Ece

[nyckylim]

are HDR images welcomed here ? if yes, here are some of my humble HDR images based on 3 exposures. all postprocessed n tonemapped with Aperture 3 and Photomatrix plugin.

 

 

Cheers

Nycky

[thompsonkirk]

This looks like fun! But I'd like to see a comparison between Tone Mapping & just using the Recovery & Fill sliders in LR/ACR, if anyone has mastered tone mapping well enough to make a comparison.

 

Kirk

 

BTW, maybe this thread should move over to the Digital Post Processing sub-forum, where more people would expect to encounter this kind of info?

[daveleo]

hi folks

 

yes, this is an open thread for us novice tone-mappers to come to grips with what this is all about, so feel free to drop your dime here.

HDR images are okay, as i THINK? tone-mapping is a poor-person's version of HDR . . . but it would help if you would also post the "middle" original image for comparison to the final.

 

Osscat . . . feel free to experiment on my stuff as you wish . . . i myself have about 100 versions of that photo . . . my "favorite" changes every day

 

i am noticing that the effects on photos through glass are very dramatic(see Ece and Pop input above)

 

i am 95% sure that you can get very very similar results using your "normal" postprocessing sliders , but i personally punch the tone-map button first to see what pops up . . . and then i walk through the step-by-step layer process (Pop will explain) as my second attempt . . . then i usually default to my own PP.

 

Kirk . . . i was so intimidated by the "digital PP" forum that i posted this here.. . . those guys are way way above my skill level and they also use Photoshop and LR/ACR (which i don't even know what that is !) and i use the GIMP and their teachings would be lost on me. . . . maybe it is possible to interlace discussions for the various softwares used ??? . . .

 

Philipp . . . the world is waiting for you step-by-step procedure

[daveleo]

dave#4, thanks very much for starting this thread, and the same to ece and pop for keeping it going. this is my first 'mapped' photo, so i'm pleased, but i hope you'll find it to be a good starting point.

 

basics:

 

• st. peter ording on the north sea. there's a long boardwalk between the town and the beach across the marshlands to minimize impact on the marsh and wildlife.
  
• the photo was taken using the m9 in bracketing mode (three 1/2 stop steps). 21mm elmarit pre-asph, 1/125 at iso 160.
  
• photoshop cs3 put the three images together using file/scripts/load files into stack
  
• auto level on each of the three layers
  
• filter/smart sharpen at 50 1.3
  
• flatten image
  
• adjust overall brightness
  
• crop to remove the unaligned edges
  
• the comparison image (before) is the lightest of the 3
  

greetings from hamburg

 

rick

 

Rick . . . that description is excellent . . . it's clear enough that even non-Photoshop users can (more or less) get what you did . . . where's that "thumbs up" button

 

and it is a different process than i used, which uses only one original image and creates and modifies two duplicates of it then flattens them.

 

for reference, we actually started this discussion in this thread:

http://www.l-camera-forum.com/leica-forum/architecture/130269-union-horlogere.html

[daveleo]

@Rick . . . . where in your steps do you set the opacities of the stacked images??

what do you set them to??

which layer goes on top (i mean the lighter one or the darker one) ?

[pop]

Philipp . . . the world is waiting for you step-by-step procedure

On your head be it, then:

Tone Mapping with GIMP contains a tutorial which explains step by step how to do tone mapping using the GIMP. Unfortunately, I could not understand any of it since it is a functional description and with my strictly limited knowledge of the GIMP I could not find out at first how to apply those functions. That was not at first a serious problem since the site provides a script for the GIMP which implements those very steps.

Being a bit on the headstrong side, I wouldn't let things stand as they were. With some determination and quite some help by Dave I was able to convert the functional description into a procedural one. The following steps ought to work in the English version of GIMP 2.6.8.

Before I start let me mention that some of the steps involve using menus or other controls in the window which displays the image itself. Others involve controls in the dialog window which shows the different „layers“ of your picture. I will denote which is which by „in the image windows“ and „in the layers box“, respectively.

Here goes -

1. In the image window use the menu Windows/dockable Windows/Layers; this will show the layers dialog box needed for many of the following steps.
2. Do this twice: in the layers box select the topmost layer, right click on it and select Duplicate from the pop up menu.
3. In the layers box select the topmost layer (if it's not already selected)
4. In the image window use the menu Colors/desaturate; select any of the methods offered in the dialog box which pops up.
5. In the image window use the menu Colors/invert; you now have B/W negative of your picture in the topmost layer.
6. In the image window use the menu Filters/Softening/Gaussian blur; the radius you choose strongly influences the result; a smaller radius gives a stronger effect. The AdvancedToneMapping tutorial suggests to start with with a radius of roughly 10% of the picture width or height.
7. In the layers box select the topmost layer; this is the layer called „the blurred layer“ in the original tutorial. Using the slider in the topmost part of the dialog box set the opacity to 75. You also might want to experiment with this value.
8. In the layers box right click on the topmost layer and select Merge down from the pop up menu. This combines the two topmost layers, leaving you with two layers.
9. In the layers box select the topmost layer; change the mode setting shown in the top of the dialog box from Normal to Soft Light.
10. In the layers box use the opacity slider to adjust the opacity of the topmost layer until you get a result you like. The tutorial recommends a value of 90% to start with.
11. Finally, when you like the results, use the menu Image/Flatten in the image window.
    

Dave says to play with different modes in step 8. He is particularly fascinated by the mode Divide.

A non-obvious use of the layers dialog box: you can make layers visible and invisible. Hence, in step 10 you can toggle the top layer on and off and easily observe the effect the mode and opacity settings have on your picture. Also, you can apply step 6 to different copies of the layer-to-be-blurred using different radii and easily select between those.

With many thanks to Dave for his help and encouragement.

Enjoy.

[daveleo]

there is some great info on the digital PP subforum . . . .

 

http://www.l-camera-forum.com/leica-forum/digital-post-processing-forum/121921-composite-technique-shoot-low-iso.html

 

http://www.l-camera-forum.com/leica-forum/digital-post-processing-forum/120819-leica-m8-hdr.html

 

 

BUT . . . you can see that this technique (overlapping multiple layers via HDR or tone-mapping) can, IMO, lead to some too too extreme looking results . . . but that's personal preference.

 

 

also here:

 

http://www.l-camera-forum.com/leica-forum/landscape-travel/85236-scotland-b-w-hdr-view-loch.html#post892786

 

 

but note that i am most interested on exactly what goes on in this process so i can do it manually . . . pushing mysterious buttons and spooky sliders is not where i hope we end up.

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[rickp13]

@Rick . . . . where in your steps do you set the opacities of the stacked images??

what do you set them to??

which layer goes on top (i mean the lighter one or the darker one) ?

 

dave

 

great question! first answer - i didn't consciously set the opacities of the stacked images, nor did i place them in any particular order (light to dark or ......). until i dig further, i'm gonna assume that photoshop did those two jobs when it created the stack. if it didn't, i would have ended up with a triple-dense image, i think, too dark to see much of anything.

 

just for fun last night, i made a stack of seven nighttime images, and it too ended up no denser than the darkest individual image. even curiouser, i think photoshop eliminated some of the duplicate figures - people who moved between one shot and the next.

 

i'll get out the manual later this weekend and see if i can learn (and share) more about the "creating stacks" process in PS.

 

a.t.b.

 

rick

 

p.s. you can include me in the hdr/tone mapping group which enjoys a little additional dynamic range but avoids the extreme 'technicolor' effects except for special purposes.