Advanced HDR techniques in Photoshop with Jack Howard

You think Photoshop is weak when it comes to HDR?
Think again.

Jack Howard, fellow RockyNook author and Director of New/Social Media at Adorama, is here to prove you wrong by demonstrating some really cool Photoshop HDR tricks. It's all about getting creative with workarounds.

You may want to watch part 1 first, or just press play below to skip to the really good stuff.



Very inspiring, thanks Jack! Another favorite of mine is tweaking the mask of an exposure adjustment layer with the gradient tool and soft brush strokes. Makes some really smooth "invisible" effects. You know, the kind that only gets the image where I want it without looking processed.
In fact, these are the techniques I rely on when tonemapping these extremely big shots of David Breashears. Just finished another piece:



Launch Panorama Viewer

David Breashears' Karakoram B in 520 Megapixel



Site update:


Long-time members of the HDRI Community forum will recognize the new look, now better matching the site theme. There are also new features: Facebook integration, a Spell Checker, and many more.

Blochi
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Saving the world, one gigapano at a time

The glaciers are melting, that's a sad fact of life.

I'm no big environmentalist, and this won't be one of these "Call to Action" posts. It never occured to me that I could make a difference. I mean, yes, my ride is a scooter with 80 miles/gallon, but that's just because I love my Vespa and I got sick of finding parking in LA ;)

And then there's people like David Breashears. A passionate Mout Everest climber, who made it his lifetime goal to educate people about the climate problem. He's matching famous photographs from a hundred years ago, and it's pretty scary how much the "water towers of the world" have dried out in this time. Check out this video clip:



It's called the Glacial Research Imaging Project (GRIP). You might have seen the New York Times Ad on Synday, on the back cover. More info about GRIP is here and here.

After seeing my 2.5 GPixel Grand Canyon pano, David went back up the mountain to reshoot these pictures in HDR and in really really high resolution. He came to me for some shooting advice. After several phone calls I sort of joined the project, doing the merging, stitching and tonemapping.
An interesting challenge. But well worth the effort, especially when the result turns out like this:


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onmouseout="karakoramthumb.src='http://www.hdrlabs.com/news/files/karakoram_thumb.png'">
Launch Panorama Viewer

David Breashears' Karakoram in 770 Megapixel



You'll get the full explanation to the glacier after Mr. Breashears is back from the mountain, did his round with the scientists, and gets his own website up. I'm just in it for the post processing.

To my knowledge nobody has done an HDR image this big before.

Here's what I learned during the process:

  • Photoshop CS4 is the only app that can load and tonemap an EXR file of 6 GB.
  • AutoPano Giga can make such a file, but it needs to be on LInear Blending, no Color Correction, and no Compression.
  • That's why Vignetting needs to be removed during RAW development (Lightroom here).
  • SmartBlend works on PC, but not on Mac. Although it still tends to generate blending artifacts in HDR mode.
  • PTGui on the other hand, works great at this size with standard PTGui blending.
  • The 64-bit version of CS4 is pretty responsive in the viewport, but every operation (load/save/sharpen/flatten) takes ages. Consdering the image eats up 10 GB of RAM, only my VFX workstation at work can actually do this.
  • Tonemapping snow is hard. Somehow it always turns out grey. Figured out that this is just a mental thing: there is no upper point of reference. So there is nothing stopping me from overdoing the local contrasts, effectively working against the overall global contrast and darkening the snow patches.
  • TIFF files can't be bigger than 4 GB.
  • PSB is the only file format that really works. Can bloat up to > 17 GB, when tonemapping manually with adjustment layers.
  • Photomatix 64-bit, made for tonemapping huge images, needs to support PSB. At least the single layer, flattened PSB - otherwise it's kind of pointless.
  • Gigapanos are strange. Tonemapping them to look good in every zoom level, all the way out and when focussing on a tiny detail - very hard.

Why did I go full HDR on this?


Using a local tonemapper on the tiles before stitching was my first idea. But that leads to a huge variation in overall brightness. Especially the clear sky tiles turn into a mess, because noise/grain is the only detail emphasized here.

On the other hand, all the snow and ice do show a very high dynamic range. A combined field of view of 320 degree makes it even worse. Compare the result with the Best Exposure Preview stitch, and you'll see that the HDR treatment does make a hell lot of sense. Although, in comparison, that preview stitch was ridicuously easy done in Autopano Giga on MacbookPro.

While my involvement probably won't stop the glaciers, it's nice to gather some Karma points while tackling an interesting HDR challenge like this.

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How to increase the Canon 7D's Dynamic Range

Despite the title, this video only has a remote connection to HDR.
It's still worth watching, especially for all you Canon-heads out there...

How to increase the Canon 7D dynamic range (Tutorial) from Luka on Vimeo.



Some remarks:


If you want to give this a shot, hop over to Luka's Vimeo page for the download links.

Although this is all just a hack, it's a very effective one (as Luka's examples show). I'm actually surprised such an aggressive grading doesn't cause more visible banding and posterization artifacts. Because after all, the recording medium - a movie file - is still compressed in 8 bits only! Even though the captured dynamic range is increased, it still has to go through the low dynamic range bottle neck that is the movie file format. Just that instead of selecting an exposure window, the custom picture style is compressing the dynamic range.

Now, if cameras would support HDR-Video formats like XDepth or HDR-MPEG, it could be done right. They would be capable to retain every bit the sensor captured, enabling grading with a similar quality you're expecting from RAW image editing. Hey, I can dream, can't I?

Site updates:


I have switched the commenting system over to Disqus. What I used previously, Haloscan, was so outdated that the company I signed up for it doesn't even exist anymore... The good thing is, that Disqus is a much nicer system with all the bells and whistles (like facebook and twitter connectivity), but the downside is that I couldn't figure out yet how to migrate all the previous comments. Which is a shame, really, some of them were really good and informative.

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Upgrade complete: HDRLabs v1.5

Phuu... Finally.
This was the first complete overhaul of the entire website. Everything works again, better than ever before. What you see now is what I intended the original design to be.

Most notable updates:

Kirt Witte shares more tips and tricks in his HDRI FAQ.


For example, did you know that you you can save post-processing time on your panoramas, when you line up the tripod legs? Later, you will only have to retouch 2 shadows for the nadir, and not 3...


Kirt's HDRI FAQ is not only bigger now, but also more accessible. You can link to any of the answers directly (like I just did with the image above), and there's RSS feeds and a search function in the side bar.


The second-best thing that happened to this website was the

Flash Panorama Gallery.


What was previously just one long page, is now divided in sections. Less messy. Better. Also highlights the best panos on the first page. Whenever a pano is available as sIBL set, you will see a download link appear. Like, on this sIBL-of-the-month. Nice cross-linking, eh? Browsing is a much nicer experience than just grabbing it from the archive - which I've also updated, by the way.

Other than that, you might have noticed new icons and new header images. There's also new links in the sidebar to the HDRI-Handbook translations (he, I'm published in Korean). New sitemap and new embedded search function. New everything.


Happy Halloween!
Christian Bloch
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Silence?

If this blog has become too quiet, then that's because the entire site is currently under heavy construction.

I wasn't planning for this. It just happened that updating to OS X Snow Leopard caused a chain reaction, breaking my website generator first, then some important plugins, and ultimately this website. Along the way I realized that the whole site requires some serious house cleaning. First victim was the German language version. Sorry "Freunde". As soon as I find a way to update German along with the English pages, I'll bring it back.

My apologies to everyone I promised a review or featurette here. Don't worry, it's going to happen, once I get this rocking boat back under control.

In the meantime, why don't you check out a new panorama: Downtown LA at Golden Hour, made from 224 exposures, resulting in a massive 18.000 x 9.000 full 360 degree EXR pano. I used the Promote Control for shooting this piece. Which, by the way, is heavily discussed by some of the most profilic pano pros with the Promote developer Arty in this thread. Great to see Arty take suggestions and ideas serious, amoung them user interface improvements, a pocket to mount on the tripod, and a back scratcher.

PS: Even when things are under construction, I still snuck in a new sIBL-of-the-month.
You didn't think I let you down, did you?

Christian Bloch
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Highlights from the HDR Symposium

Stanford's HDR Symposium turned out to be very interesting event. The collective brainpower of a small nation, crammed into a single room - you bet the air was sizzling from ideas and strong opinions.



Highslide JS



Here's a quick recap of some selected points of interest:


  • Marc Levoy explained how the Camera 2.0 project will enable a community-driven approach to push computational photography forward. Key element is the departure from "black box" firmware, in favor of a fully scriptable open-source platform.
    Levoy further recommends Animal Eyes as reference book for everyone building capturing devices.

  • Helge Seetzen from Dolby Labs shared some interesting insights on the difficulties of driving Local Dimming hardware. He called color LEDs "little buggers" for being notoriously inconsistent in color. But exploiting their flaws rather than fighting them leads ultimately to an even better display. For example, spectral leakage turns into an advantage when driving 6 instead of 3 primary colors, resulting in a much wider gamut.

  • Jack Tumblin lets us rethink what we consider a "great image", and explains how current tonemapping methods might be missing the point. He honored Renaissance artists like Rembrandt as excellent tonemappers, using artistic liberty to cheat the lighting to create more evolving images.
    Tumblin recognizes the "evocative HDR Look" for inducing an emotional response, but the result is often achieved by muddling through. In this regard he proposes a tonemapping approach, that looks beyond the pixels on the screen, and rather makes a distinction between surface colors, reflection, and lighting. This would allow more controlled look-finding. For example, you could tweak just the lighting in a photo, without worrying about side effects like "dirty" or "super-glossy".

  • James Ferwerda is hitting the same vein by proposing an extension of the La*b* color space with variables describing the glossiness of a material: c* for contrast gloss and d* for distinctness-of-image.
    In a perfect execution of the scientific method he did a field study where participants rated the gloss impression of a rendered ball, which resulted in a psychovisual gloss model. Although originally geared towards CG imaging, this model could be interesting when applied to photography in general. Also, Ferwerda dropped a new wording that I find very appropriate: High-Fidelity Imaging. Yay.

There was a lot more going on, and I will most certainly get into detail in later posts. HDRI is a pretty wide field, and this HDR Symposioum surely succeeded in bringing the top guns from adjacent fields together. Kudos to Joyce Farrell for flawlessly organizing this remarkable event.

Just one question remains unanswered:
Who owns tonemapping? The camera, the photo software, or the display device?

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