The HDR Life Cycle: Tone Mapping Puberty

HDR Tutorial - Photomatix Intermiary 32-bit HDR photo

This awkward 32-bit TIFF still needs to distribute its values.

Sparing no uncomfortable detail, The HDR Life Cycle series explores and attempts to explain the miraculous creation of an HDR photo.

HDR Lifecycle Index:

1) Conception - planning & shooting
2) RAW Infancy - prepping photos for tone mapping
3) Tone Mapping Puberty - tone mapping & Photomatix
4) Photoshop Maturity - Layer blending & final edits

Once your young and impressionable bracketed DNGs are exported from Lightroom to Photomatix for tone mapping, the final HDR image rapidly starts to take shape. When tone mapping takes place, it can add surprising definition to areas of previously low contrast. The photo really starts to fill-out and come into it’s own. Likely, you’ll find value and tone in regions you had never considered before (I’m talking about the photo so get your mind out of the gutter… perv). 

Photomatix and tone mapping can be a tough time for even the best prepared source photos, but hopefully this article will help guide you through the process smoothly.

If you’re unfamiliar with HDR photography, it’s quite interesting stuff. Check out this (creatively titled) article “What is HDR Photography?

Exporting from Lightroom to Photomatix

In Lightroom click File > Export. In the preset menu select “Photomatix Pro” from the list. If you don’t have this option, you can download the “Lightroom Export Plug-in to Photomatix Pro” for free from the Photomatix web site here.

The goal is to preserve as much of the original image data as possible. For that reason, I ALWAYS export TIFF files with compression set to None. For color space I use ProPhoto RGB mostly because it has the word Pro in it, but it also has a wider color gamut than Adobe RGB 1998. However, neither printers nor monitors can display this difference in depth so really, take your pick. (For your color space-nauts, this article explains the differences in much more detail.)

Don’t check the box “Image Resizing”; write in those keywords if you want and then hit “Export.”

HDR Tutorial - Lightroom Export to Photomatix Preset

HDR Tutorial - Photomatix Load Bracketed PhotosOn the next dialog that pops up, leave everything unchecked except “Automatically re-import into Lightroom Library” and “Stack with first selected photo.” This keeps organization automated. When we’re finished making our tone mapped image in Photomatix, the resulting TIFF will be sent back to Lightroom and we will be spared from manually importing it ourselves. If this doesn’t jive with your work flow, feel free to leave these boxes unchecked. Just remember after you click “Process” in Photomatix, to save the tone mapped image from Photomatix to the folder of your choice. Otherwise you’ll have to redo it (booooo…).

Andrew: But what about the other options Andrew? They seem important.

Andrew: Great question Andrew… o_O. Here’s a breakdown of the options from my perspective:

  • Align Images – If you took your images on a tripod (and it didn’t move during bracketing) then there’s no need to check this box.
  • Reduce ghosting artifacts – The automatic option works sometimes, but it’s inconsistent at best. The selective deghosting tools is decent but only allows you to substitute in a single source image into the ghosted area. Later, in Photoshop, we can do this much more dynamically using semi-opaque brushes, masks, and adjustment layers. I’ll show you exactly what I mean in the next stage of the HDR Life Cycle.
  • Reduce noise – Lightroom’s noise reduction algorithms are smarter and better, this is why we corrected this part of our images in RAW Infancy.
  • Show intermediary 32-bit HDR image – This doesn’t do anything to the process, it just shows you what the compiled HDR image looks like before tone mapping. I never check this, but have heard of others saving all their pre-tone-mapped 32-bit HDR images in case they want to create a different tone mapped image later… if you follow. Since I have all the source images, I don’t see the need to take up hard drive space with this intermediary image. That’s not to say this 32-bit behemoth is insignificant. In fact, it’s easily the most important step we’ve taken in our HDR development. To really understand why it’s absolutely essential, first we need to look more broadly at Photomatix and the tone mapping processes.

How Tone Mapping Works

HDR Tutorial - Photomatix Merging to HDRHeavily influenced by the work of J.K. Rowling, HDR software developers coded Photomatix to primarily use incantations to tone map your source images (if you check the “Remove Ghosts” box, it uses Link’s mirror shield… but this isn’t the article for that). This HDR tone mapping magic comes in the form of several algorithms executed while Photomatix mesmerizes you with the “Merging to HDR” progress bar. It’s this magic that merges all the LDR (low dynamic range) sources photos into one image with high dynamic range. Here’s what happens in (somewhat) plain English.

It Starts with 32-bit Depth

Remember when Playstation 1 was the bomb with its sweet 32-bit graphics. Ya man, 32-bits were it. (I beat all three original Crash Bandicoot games by the way.) Then remember how Super Mario 64 came out for N64 and made you wish you hadn’t spent all your allowance already… Well, the HDR 32-bit TIFF that Photomatix compiles has nothing to do with that stuff and it’s time to move on anyway. It wasn’t Mario’s fault he had extra polygons.

The tone mapping algorithm combines all the values from the 8 or 16-bit source photos into one large 32-bit TIFF (viewable if you check the box ”Show intermediary 32-bit HDR image”). Essentially, it creates a super Voltron image that even has a scaled-up histogram due to its extended definition. Without adjustment, this intermediary image is quite visually Rubenesque (that’s just a polite word for chunky) and appears somewhat posterized. This is because a majority of an image’s data is stored in the mid-range. By definition it has a truly high dynamic range since it contains the value data from the source photos, however it’s called “intermediary” because it is has yet to be completely processed and realize its full potential as an HDR image.

Photomatix Intermiary 32-bit HDR photo

This 32-bit intermediary TIFF has all the data we need... now to spread it out.

Adjusting Photomatix Sliders

With this data-rich 32-bit TIFF we can now use  the Photomatix sliders to proportionally distribute the values over the whole spectrum. It’s not perfect, and the final output of Photomatix will still need some Photoshop editing, but this is the step that really adds the “wow” factor. Knowing how to adjust the sliders to get the results you envision takes a large amount of practice and tinkering. My general rule of thumb is to get a majority of the image looking close to perfect. If the sky is wacky or a section of shadows has lots of noise, this can be corrected in Photoshop.

Although I talk about each slider individually, I’ve created a simple graphic that reflects how I think about the sliders in Photomatix. At the same time, I highly encourage you to create your own mental definitions for these sliders and decide for yourself how you like them. This is art, there are no wrong answers.

HDR Tutorial - Photomatix Tutorial

These are just my loose mental notes. Play with the sliders in Photomatix to figure out what they mean to you.

Slider Details

(Below are conclusions that I’ve come to on my own from using Photomatix. For the official definitions, see the Photomatix Help Page.)

Strength – This is what you bought Photomatix for. There’s no reason to go less than 100% because you can always lower the opacity of the image in Photoshop later.

Color Saturation – Photoshop is the league MVP in color control software. Boosting saturation now only limits options later.

Luminosity – I think of this as the “glow” control. This controls how smoothly areas of contrasting values blend. Higher values will make the image lighter, but also more hazy. I used to keep this really high, but now try to push it as low as possible to preserve detail.

Detail Contrast (a.k.a. Micro Contrast) – This adds “grit.” Similar to the clarity slider in Lightroom or the middle slider of a Levels adjustment layer, it effects the contrast ratios in the mid-tones of the image. I rarely move this slider lower than 9 in order to keep my details as intact as possible.

HDR Tutorial - Final Photomatix Tone Mapped Image

This is the final Photomatix tone mapped image, ready to be blended with the source images in Photoshop.

Lighting Adjustments – Distributes the light in the image. As you slide this setting around you’ll notice that the farther left you take it, the more surreal the image looks. Conversely, the farther right will yield a more realistic look. This is really subjective, but I aim to make the image feel as real as possible while also evoking emotion. With numerous exceptions, I usually land between 3 and 10. For every image I always click across the entire scale from -10 to 10 to see all my options though.

White/Black Points – I use these to keep my lights and darks from clipping and to create realistic exposure. I don’t use it to create drama in the scene because a simple Curves of Levels adjustment layer in Photoshop later will be more flexible. Right now I’m focused on getting out of Photomatix with a malleable piece to my final HDR puzzle which gets solved in Photoshop.

Micro-smoothing – This smooths out small areas around contrast and is good for slightly blurring out noise on smooth surfaces. Most often this stays below 1 because I would rather have too much definition than not enough when entering Photoshop. Rarely I go above 2, and I dare say I’ve never ventured above 3.

Other sliders – If I didn’t mention it, it means I don’t move it out of its default position.

Mistakes to Avoid

Before clicking “Save and Re-import” go through this brief mental checklist:

  1. Are the details too hazy? The earmark “glow” found in beginner HDR images is most easily removed in Photomatix by playing with the Luminosity, Details Contrast, White/Black Point, and Micro-smoothing sliders. Although still possible, in Photoshop it will take much longer to control this issue.
  2. Do the colors belong in Candy Land? Photoshop will do a much better job helping you get vibrant, saturated colors if that’s what you seek. By boosting color in Photomatix, you’re taking the irreversible step of flattening all the data together. Do the right thing, just say no to over-saturation in Photomatix.
  3. Am I overthinking this? – Jk, NEVER EVER think this when editing a photo or it’s all over. :-)

Click “Save and Re-Import”

This will automatically warp whistle you back to Lightroom where you’ll find your brand new tone mapped image stacked in with your source images.

Few, you made it through Tone Mapping Puberty! Only one program left. Are you ready for the last stage of development in the HDR Life Cycle, Photoshop Maturity?

Onward to learn about the FINAL phase in the HDR Life Cycle: Photoshop Maturity! >>>

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4 Responses to The HDR Life Cycle: Tone Mapping Puberty

  1. uav predator April 27, 2013 at 2:42 pm #

    The pro perk would help you when you need to get a stun around a corner very fast.
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  2. A.Barlow March 15, 2012 at 12:13 pm #

    Actually very close to how I work through mine. Nice read.

  3. Cheziannhe March 15, 2012 at 6:33 am #

    i wasn’t really aware and familiar with tone mapping and while i was reading the entire flow, i got confused with some of the tips and tricks as well…

  4. Len Saltiel March 14, 2012 at 10:26 am #

    I always like to read about other workflows, especially ones that are different from mine Andrew. I always learn something. I generally follow the Trey Ratcliff approach with some modifications. What I have learned is that there are many different paths to great images. Really nice write-up.

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