LR Merge to HDR and Adobe Profile

@Tony_Kuyper recently posted a link to an article of his about using Linear Profiles in Lightroom.

@Kris_Smith posted an image where she used LR HDR Merge to blend exposure brackets for a high dynamic range scene, and she tried using raw files with a Linear Profile as the starting point.

I normally blend exposure brackets manually using TK luminosity masks, but I was interested in Kris’s idea about what profile to use for HDR Merge. Does it make a difference? So I played with it a bit using a 4 image bracket of a sunset from Cape Cod, and trying HDR Merge. I did this starting from raw files with LR profiles of Adobe Color, Adobe Neutral and Linear. I did this using the “Auto” option checked in Merge HDR.

Here are the same raw files under different profiles (I’m showing only the darkest and lightest brackets for each, there were two other intermediate exposures used for the merge as well).

The same raw files with different profiles

Adobe Color Profile

Adobe Neutral Profile

Linear Profile

As Tony discusses in his article, Linear gives a flatter, darker starting point. My intent was to see how profiles affect an HDR Merge (including auto checked). Here are the DNG file outputs of HDR Merge with auto checked. No changes were made to any sliders, other than what Auto did.

Adobe Color HDR Merge with Auto

Adobe Neutral HDR Merge with Auto

Linear HDR Merge with Auto

Most people using HDR Merge would make further tweaks to the DNG files sliders, but for the purposes of this discussion I just wanted to see how the different profiles yielded different results as a starting point for further processing (rather than as a finished product).

My observations (and maybe I’m ignorant about how HDR Merge is supposed to work, but I don’t use it all that often, however Kris’s post got me curious intellectually).

Adobe Color profile adds a lot of contrast that risks blowing out the area near the sun, and adds contrast in the shadows that would need to be recovered with further processing. Using Adobe Neutral profile protects the highlights near the sun pretty well, while adding less contrast to the landscape. Linear produces the flattest file of all, but to my eye it does not have a huge advantage on highlight protection over Neutral (in the area near the sun). If you want the most control over further adjustments to the DNG file, then Linear gives you more latitude to bring in contrast where you want it. And after seeing this, I would never use Adobe Color for HDR Merge again, it doesn’t handle extremes as well as Neutral. If you didn’t want to spend the time to take more manual control over adjustments using Linear, Neutral might be a decent compromise. It depends how much work and control you want to put into it. YMMV :smile:

I think the biggest takeaway for me is that the profile of the raw files does matter in terms of how the HDR Merge starting point DNG file looks. It’s something that I probably failed to think about enough in the past. I do most of my blends manually with LM’s rather than with HDR merge, but I’m sure that what profile one uses as a starting point matters there too.

@Kris_Smith I did try an HDR Merge with Linear for the sky brackets, and Neutral for the land brackets. Here is that result. It didn’t handle the sky near the sun quite as well as Neutral.


Oh and by the way, the tiny figure over to the left is NPN’s own @Karl_Zuzarte , who was kind enough to introduce me to this location. Thanks, Karl.

Anything for the good guys! A lovely sunset that you processed so well!!

Thanks for this, Ed. Would I be accurate to say that the histogram for the Adobe Color HDR Merge DNG file is spread out a lot left to right, whereas the histogram for Adobe Neutral HDR Meege is more centered, away from the left and white edges, and Adobe Linear HDR Merge is centered even more than Neutral? The histograms of the 3 files would be interesting to see.
Do you see an advantage of Linear Profile HDR Merge, over your traditional method of blending via luminosity masks?
Thanks too for the link to Tony’s article.

I never thought about using linear profiles in this manner and would have a hard time making a good case for using linear profiled RAW conversion directly in an HDR merge scenario. I’m somewhat surprised and impressed the the linear HDR merge was better than the Adobe Color HDR merge. The reality is that just switching to a linear profile, as mentioned in the linked article, is actually taking a step backward to a more native representation of the RAW file data. Pushing this unprocessed data directly into HDR Merge is likely the reason for of the more unprocessed looking HDR merge image that resulted. The main reason for switching to a linear profile, in my mind, is for the control and creativity it makes possible in Light Room/Camera Raw. That means using the sliders in the Basic panel or at least clicking the “Auto” button. Whether or not this added level of control would still be available in the HDR-merged image is not something I could speak to as I’ve not tried this. Bottom line is that I wouldn’t advocate using a straight, linear profiled image for anything other than the starting point for making Lr/Cr adjustments. There may be additional uses for the linear profile and this experiment may have turned out better with a linear profile + Auto starting point. However, it is important to keep in mind that applying the linear profile creates, by definition, a less-processed image. That opens up new opportunities, for sure, but exporting the immediate results to another process seems to have missed an important step.

The histograms of the 3 files would be interesting to see.

Merged DNG - Adobe Color with Auto
ZZ_Adobe Color with Auto

Merged DNG - Adobe Neutral with Auto
ZZ_Adobe Neutral with Auto

Merged DNG - Linear with Auto
ZZ_Linear with Auto

Linear is darker, and “flatter” the least “processed looking.” Adobe Neutral looks more “processed”, and Adobe Color even more so.

I think you should first be asking that question a different way - Do you see an advantage of HDR Merge (using a traditional profile such as Adobe Color or Neutral ) over manual blending via luminosity masks? Put Linear aside for the moment. The two are very different blending approaches. HDR Merge is easier to use initially, with just a few clicks you get a merged DNG file that can be processed further using the familiar LR sliders. However you do not have full control over how the merge is done, the software does some of that for you. And I have sometimes had issues with things like moving water where the blend produces results I don’t like. And sometimes you get halos on high contrast edges like horizons. So you gain ease of use and speed for less control, and some possible quality issues on subtle things. Manual blending using masks takes more time to learn how to do, and takes longer to do with a given image, and requires PS and luminosity mask software like TK. Once you become accomplished at it, I do believe it can produce better results because you have much more control how the blend is done. For example with waves, I can pick the bracket the blend uses, and avoid the issue of HDR Merge where sometimes you get the waves blended from different exposures and they look less crisp. You can also put in extra effort to prevent things like halos.

A good example in my Cape Cod image is the extreme highlights in the immediate area of the sun. When I do manual blends, I can use a very dark exposure, pick a very restrictive lights luminosity mask, and blend in that sun area from an exposure which is dark enough to maintain detail near the sun. I can control this. As seen in the HDR Merges above the area near the sun looks different based on the profile used for the raw files. This happens “underneath the hood” in the HDR Merge software, and I have no control over how the merge handles that area. I have to accept whatever the HDR Merge spits out for that area, and then try to work it further in LR.

So the two methods have different tradeoffs in ease of use, speed, level of control, image quality. It depends how you value those tradeoffs. I do the vast majority of my blends manually, and rarely use HDR merge, because I want more control, and am willing to spend the extra time to get it.

Even though I rarely use HDR Merge, I started this discussion because @Kris_Smith had the idea to try an HDR merge using raw files with a linear profile. (which as Tony points out is probably not their intended use) I was curious if using different profiles for the raw brackets affected the blend or not. When I have used HDR Merge in the past, I often didn’t like how it handled extreme highlights (like the sun area). This in fact is one reason that I switched to manual blends. But a Linear profile darkens the overall image, and preserves more highlight detail than say Adobe Color. So I was curious about whether that might affect how an HDR Merge handled the sun area.

I think my biggest takeaway from this experiment is that if you do use HDR Merge, using an Adobe Neutral profile probably creates a better (ie flatter) starting point for a merge than using Adobe Color. It protects highlights and shadows better, giving you m ore latitude for further adjustments . And as @Tony_Kuyper points out using a linear profile with HDR merge is uncharted territory, and it may have unintended consequences for how the “underneath the hood” work of HDR Merge happens. It may or may not really make any dfference. What my experiment shows is that it does create different starting points for the Merged DNG file, but I did not try to look any further than that. Tony’s work on linear suggests that a big advantage to liner+auto is that it makes subsequent use of the sliders in LR more predictable. In my experiment I did not try to look at that aspect at all. I was just curious if Kris Smiths experiment affected the HDR Merge starting point.

I plan to stick with doing Manual Blends, I think it has advantages for me. But many people don’t want to put in that much time and effort, so HDR Merge is faster and easier to use, and the quality differences may not matter to many folks. But if you do use HDR Merge, then using Adobe Neutral profile over Adobe Color provides a merged DNG file that is a flatter starting point, giving you more control over how you use LR sliders to adjust the DNG file.

And Tony is right, Linear may have nothing to do with HDR Merge. Please don’t assume that Linear with HDR merge is a valid way to go, let alone better than HDR Merge with more traditional profiles. But if you do plan to use HDR Merge, using Adobe Neutral creates a better starting point than Adobe Color, or other aggressive profiles like Adobe Landscape.

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While this was not the intent of my looking deeper into what Kris Smith did, the merged DNG file does indeed allow you to change the profile of the DNG, including to Linear. So merging raw files with an Adobe Neutral profile in the brackets, creates a merged DNG where you can change the profile to Linear, and it makes the DNG image darker and flatter looking. At that point I suspect the Linear advantages on a single raw file discussed in your article (predictable slider results, color, etc.) , might well carry over to the Merged DNG. This may be a place where Linear has some utility in a Merged DNG workflow (in the subsequent processing). And it may not be in the creation of the original DNG file itself.

Some quick and dirty playing with a Neutral Raw/Linear+Auto DNG feels like those advantages do carry over. This assessment is subjective, I’d have to do a bunch of them to feel better about saying that for sure.

Thanks Ed. The histograms are very interesting, generally what I expected.
I’ve mostly used HDR Merge in LR, for its ease. But I now have TK7 and will be practicing blending with luminosity masks. It’ll be fun to compare the two methods first hand.
Thanks for sharing this experiment with us.

Wow…what a great look into these, Ed. Thanks so much for your work and examples - including the histograms which I was wondering about, too.

It wasn’t my intention to misuse a Linear Profile, and quite frankly I don’t see how this is possible, but to expand the possibilities with HDR merging however it gets done. After looking at photos using various profiles, I saw that the Linear one Tony created for my G9 seemed to preserve both shadows and highlights while affording greater nuance with the sliders. I had just done a bunch of exposure bracketing during a workshop and despite that wasn’t having the best success processing those images, so I tried it with a couple.

First changing the resulting DNR to the Linear profile and then changing the bracketed images before merging. The results were different as you’d expect, but I think it holds some promise to produce more natural looking photos. My issue with HDR is its over-the-top final results.

Because the initial file is so flattened by Linear, it can be off-putting at first. We’re used to a more contrasty and saturated image, but you can bring it to that level pretty easily. In my experience I have to move the sliders way more than I would with an Adobe or Camera Matching profile and that takes getting used to. I will continue to play with it.

A question for @Tony_Kuyper - it seems using Linear Profiles is most beneficial for or designed to work best with images that are pushing the histogram either far left or far right. It seems it would not be as effective a starting point for shots with even histograms - those that spread from left to right without clipping or pushing the exposure in either direction.

Kris - I’m not sure you necessarily mis-used Liner Profiles. Like I said, I don’t use HDR Merge that often, and primarily use manual blends with LM’s. But today I finally got around to processing my shots from spring 2021. I had some backlit tree images that were difficult to blend manually, so I tried using HDR Merge. Example below

I tried various profiles to process this. What I am finding is that whatever profile you use on the bracketed raw files carries over to the blended DNG file. But once you have the DNG file, you can change the profile of the DNG itself. So I think maybe it doesn’t matter what profile you use on the raws. But for very high contrast scenes, once you get the merged DNG you can set the profile to Linear, and then you get all the advantages Tony talks about (more predictable slider results, colors, etc) on the DNG file. In the tree image above, changing the profile to Linear did a great job protecting both highlights and shadows. This image would have been a bear to process as a single image. And LM’s would be tricky to use to blend this, so HDR merge was the way to go for this scene.

Yes! This is exactly my experience - it was my contrasty big log sunset that was my bugbear.

I have been setting the profile of the raw files for the merge to Adobe Neutral, and then on the merged DNG changing the profile to Linear. But I suspect it may not matter what profile you use for the raws, I think what matters is using Linear on the DNG, which leads to Tony’s advantages on a single file.

@Ed_McGuirk – Thanks for your insights. This does make a lot sense. I too have found that the profile associated with the DNG can easily be changed once the DNG is opened in the RAW converter. This also gives a little insight into what Adobe is doing “behind the curtain.” It would seem that, if HDR Merge is profile-independent, then the “blend” is happening with the RAW data itself and not the profiled data. If so, that would be a very good thing and would account for your ability to successfully switch to the linear profile after HDR Merging.

WRT @Kris_Smith query, I’m using the linear profile for everything at the moment, not just high-contrast images. Beyond managing highlights and shadows better, I just find that the sliders in the RAW converter work better with whatever I’m trying to do. It also feels like there is some increased possibilities for creative exploration since the application of the linear profile creates such a flat image that my preconceived ideas of how the image “should” look are erased and I can approach it’s development with more of a “blank slate” approach. I appreciate that this approach won’t work for everyone, but I do like the additional creative freedom that the linear profile seems to provide.

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Wonderful information here! I’ve been jumping into explorations here too, mostly with single exposures but a few older brackets with which I was never pleased. LR’s Merge to HDR is certainly an improvement over any of the HDR programs I’ve tried in past years, and I love what the Linear profile does for both HDR and for single images! I love being able to tweak sliders to bring out what I want in an image! And with Linear, as Tony points out, the sliders behave so nicely.

I’ve heard that LR/ACR somehow “recovers” some highlight detail, and a characteristic of that seems to be the little bump at the right end of the histogram in cases where there was some overexposure of the highlights. I’ve wondered with some skepticism how it does that, but with the linear profile the histogram has been pushed back so whites are less likely to be blown and this little bump is not there. So I have much smoother tonalities in the brightest tones.

I tried this and you’re right. I used a landscape where there was a significant tonal and color difference between the Adobe Landscape and Linear profiles. I changed each of the 3 subs to Adobe Landscape and did an HDR, then changed each to Linear and did an HDR. They reflected what I expected in that the Adobe Landscape DNG had more color and contrast, but when I changed it to Linear it looked like the version done with linear profiles to the subs, and the converse. The two were identical except for the tagged profile. So the HDR apparently isn’t using the profile as such, it is only assigning it to the DNG, which can be changed.

I didn’t have an image as good for the test as @Ed_McGuirk’s beach scene, with the important area around the bright sun, but I’d bet the same test would hold for that image.

As Tony Kuyper speculated above, this may be due to Adobe’s HDR Merge working with the “real” raw data independent of profile in the base raws. Then the merged image comes out with an expanded dynamic range 10 vs. 5 stops, and the Linear profile does its thing on the merged DNG.