HDR

I’ve had a number of requests and inquiries about processing technique, so I decided to put together a mini-tutorial on some of my most commonly used tools and techniques using this picture as the example. This will be a long post… but I hope worth the read.

First, start with great subject matter . This is Frank Lloyd Wright’s winter home and residential architecture school, Taliesin West, in Scottsdale, Arizona. Let’s look at how we got to this result given the original images.

At right, the original image.

The exposure details are: ISO 100, f/4.0, 1/1250. While the picture is decent, there is a huge black void just right of center (the building’s kitchen), and there is detail lost in the studio area to the left (large white canvas areas).

Also, the sky lacks drama: it’s a bit flat.

The picture doesn’t adequately express the impact of the building material — rock from the immediate vicinity of the building mixed with concrete. There isn’t enough contrast or texture to accurately reflect the experience of these materials in this building at the time I was there.

Here’s exposure two. Same ISO, same f-stop, 1/640th. I see a dramatic difference in shadow detail available, which PhotoMatix will take advantage of nicely for us.

However note that with only three exposures, and hand-helds at that (I was on a tour, and unable to take my time for setup), we still need some help on those pesky shadow areas. In an ideal situation, I would have had the tripod, and make seven exposures (at f/4, three each at one stop intervals below and above the “middle” exposure setting.

More on this later.

Here’s exposure three. This one is f/4.0, but at 1/2500th. This will provide loads of data for the highlight areas which are quite void of information in the original exposure.

There’s nice depth in the Arizona sky as well.

I also find the foreground detail and water tone useful for the finished project.

Here is a snapshot of the PhotoMatix settings. PhotoMatix is an excellent tool for generating high dynamic range images from multiple exposures. It includes a number of adjustments, and in this on I boosted the saturation a bit (which is almost always necessary, given the trade offs HDR software makes). I also selected “very high” light smoothing, which means this blended image will have few of the artifacts I personally find annoying when I’m going for a realistic, as opposed to some kind of scifi, effect.

With this image I am definitely looking for more realism.

In the original, I generated the HDR in 16-bit depth (just because I want to retain as much data as I can as long as I can).

Time for PhotoShop.

If you click on any of these embedded images, you can see larger renditions for details. This is the TIF, created by PhotoMatix, loaded into Photoshop.

As you can see, I created three additional layers to produce the final image. This first is a layer I will create to address sharpness, texture, and contrast issues using the LucisArt “Exposure” filter.

The second additional layer uses the gradient tool to create more drama in the sky.

The third deals with what I find is a distraction in the foreground — the stone deck surrounding the pool.

Here is the LucisArt tool with the final settings I chose to use for this image. [Note: the LucisArt filter only works in 8-bit depth mode]. As you can see, the tool has two “adjustments” in the “Exposure” filter. The round shapes along the bottom seem to determine the pixel radius at which the tool operates for a given filter application, while the slider (set here at 50) seems to control the “power” of the filter effect. I am making all of this up, however, as I have not consulted any documentation at any time. Play with the tool on your own images: you’ll find what degrees of impact you are comfortable with.

LucisArt has a dramatic impact on your image — and it can be a bit scary. But fear not, for we shall use a mask, our brush tool, and opacity settings to ensure we get enough, and not too much, impact on our finished image from this tool.

And look at the improvement in those very dark shadows! Loads of detail to enrich the final image. And LucisArt helped dramatically in a problem area caused by hand-holding the three original exposures. PhotoMatix attempts to align the image — but does so around subject matter at the center of the image. LucisArt Exposure has had a “sharpen / unsharp mask” effect on some of the “fuzzy areas” of the original HDR — especially in the tree at right.

On the negative impact side, it is easy to see the “pixel damage” that the LucisArt filter has done to the sky. I almost always mask the sky from the LucisArt filter for this reason. That is, I mask out areas of the original image that need the detail and integrity of the original, and use the mask and brush tools to allow the magic of the LucisArt filter to effect the final image where appropriate.

In this case, after applying the filter (clicking on the big “check mark” in the LucisArt tool), I immediately did an “alt-click” on the mask icon in the layers palette to create the mask. This masked the entire new layer from LucisArt, leaving my original image showing.

I then took up the brush tool at 300 pixels and 70% opacity, and started to paint away there areas of the LucisArt-filtered image that I wanted in the final image.

Play around with the brush and these masks on your own: you’ll get the hang of it quickly. With layers and the ability to switch between foreground and background brush color, you can do and undo to your heart’s and your image’s content. I played around for quite some time, but there were a couple of interesting learnings here.

1) LucisArt Exposure is perfect for bringing out contrast and texture on surfaces like the concrete and stone, the redwood beams and trusses, and the vegetation on the mountains behind Taliesin. I allowed lots of the LucisArt filtered image to come through in those areas.

2) I thought that the filter did too much damage to the water in the pool. So I switched the brush color from background to foreground, and restored that area to the original. There are cases where I’ll even import one of the original exposures, and create a mask to bring some aspect of one of the original frames into the finished product. Perhaps I’ll do a tutorial on that some day too.

3) I determined that the foreground stone needed a bit more texture — in fact I did a final pass to ensure that all stone surfaces I could find were in the 60-70% opacity range providing great texture from the LucisArt filter layer. I toned down the grass a bit, since it looked a bit too beard-like with full texture from the filter.

If you look at the enlarged image, you can see the effect of these brush strokes on the mask for the background copy layer. There the mask is white, I have allowed all of the LucisArt-filtered layer to show through, where you see gray, it is partial opacity. Where the mask is black, the original data shows through in the final image.

Still not entirely satisfied: I want to ensure that the clear focus is on the main building. This will involve creating a new layer to place a gradient in the sky, and a new layer to place a gradient over the foreground stone and the pool.

The gradient tool took me a while to understand, but in this case I did this:

1) Created the new layer by clicking on the new layer icon in the layers palette (Layer 1 in this snapshot). I selected the gradient tool, and the “foreground to transparent” option. I set the blending mode of this layer to “Overlay,” which adds contrast. I then mouse clicked and dragged from the top edge of the sky down to the top of the building, and released the mouse button. The gradient was created as you see it here — all I had to do was adjust the opacity, in this case to 65%.

2) Created the final layer by clicking on the new layer icon in the layers palette (Layer 2 in this snapshot). I selected the gradient tool, again using “foreground to transparent” option. And again set the blending mode to “Overlay.” But this time I started in the lower left corner of the image, and click-dragged toward the fountain in the middle of the triangular pool. I added another click-drag from the lower right toward the fountain, but not as long. Set the opacity to 65% to achieve the focus on the building that I was after in this project.

I would love to receive feedback on this tutorial, either here as comments, in Flickr mail, or you can email me at “tim at synopshots dot com.” Thanks.

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