Post-processing techniques

On previsualisation…and making the best of what you’ve got

It took us 3 long and strenuous days of hiking to get here, but the view alone was worth it. I couldn't believe that only 2 days earlier I was standing on top of that wall. What an incredible feeling (click to view larger).

I (and many others) preach the benefits of doing the grunt work before taking a photograph, on previsualizing your shot as (or before) you compose it. Basically, we preach shooting with a purpose, not just aimlessly point your camera at a scene and hope for the best.

Now, I wish I could tell you that’s what I did here, but I’d be lying. When I took this image, I was strongly drawn to the impressive, almost 3000ft tall, wall standing in front of us. Those shapes and textures were seemingly adding to its majesty. However the light was somewhat lacklustre and the resulting image even more underwhelming.

This is the original image processed in Lightroom 3

As you can see, while a beautiful sunset was raging on the adjacent valley, there simply wasn’t enough light to make this landscape come alive. So that’s how it was until this week-end when I accidentally stumbled across this image in my archives. After messing around with it in Nik Color FX Pro for a little while, I thought I’d give it a go in Black and White. While a lot of people use B&W to salvage a so-so image, I come at it from a different angle in that I am extremely picky in selecting potential B&W candidates and only ever have a few that I think are worthy. So doing this conversion was a bit unusual to start with.

In any case, the first step in my B&W conversion workflow involves (and most often is limited to) a little tour in Nik’s Silver FX2 (disclaimer: I am NOT sponsored by these guys, just love their products). I usually start with the High Structure (Smooth) preset then make it my own to suit the particular image I work on.

This is the image after Silver FX2 processing

You can see here that the textures in the rockwall pop out quite a bit more, but to be frank, that doesn’t quite do it for me. I want to make them pop even more so and want to contrast them from the surrounding hills and sky. While I would normally try and do this directly in Silver FX using the control points, I chose to take the image into Photoshop as I needed a bit more control than Nik gives me.

In Photoshop, I first added a levels adjustment layer to slightly bring out the midtones and highlight in the middle section.

The first step in this case is a really mild one as I made slight adjustments to a levels adjustment layer which subtly brought out the highlights in the rockwall while increasing contrast ever-so-slightly in the midtones. In the grand scheme of things, this step may have been unnecessary. However since my desired outcome on this image was a progressing throughout the process and was a moving target, it seemed like the right thing to do at the time.

The next step is where I made the most dramatic changes with local curves adjustments

The next step is really where I put the defining touches on the image. At this point, I had a much clearer idea of what I was looking for after much hesitation and trial. In this case, I used a curves adjustment layer and increased contrast quite drastically. The changes were kept localised to the rockwall by carefully masking out the sky and bottom third of the image. As you can see here, the rockwall textures jump at you revealing the ruggedness and majesty of the terrain. The only remaining bit left to do to complete my vision was to darken the top and bottom third of the image to take them out of the image, so to speak, and lead the viewer to concentrate on the rockwall exclusively. I did so using another levels adjustment layer masked to only affect the sky and foreground hills. To close the loop, I added a slight tint for the final look using the color balance adjustment layer tool (adding some blues in the shadows and yellows to the highlights).

As you can see through this process, while planning my images ahead of time certainly provides a better for success, it is important to keep one’s mind open to different possibilities. In this case, not only did I not previsualise the image at the time of capture, I didn’t have a clear idea of what I wanted to do with it when I started processing it. The final image really was formed in my mind throughout the editing process. Now, I don’t recommend doing that too often as it is a rather time consuming, ineffective and not often successful process.

Tune in next week for a nice gear review on the F-Stop Gear Tilopa BC photo backpack.

Blending Exposures

As I often get requests to explain how to manually blend exposures in photoshop, I figured I would finally post this older article of mine straight on my blog (this post appeared on Bret Edge’s blog some time ago) and make sure it is available to my readers. This alternative method can not only replace GNDs in some circumstances, but offers significant advantages over both GNDs and the automated HDR options. This technique involves blending multiple exposures using masks and layers in Photoshop. Now this method is not the end all be all, mother all of all options, it doesn’t work in every circumstance. If you dislike spending time on your computer, this is probably not for you. However, if you believe that you should use every tool you have at your disposal to make the best image you can, then you ought to give this method a try.

Moroccan Atlas Sunrise

This photograph is a blend of two exposures merged together in photoshop

Enter Exposure Blending

Let me first start with a disclaimer: as I indicated above, this is not a panacea, or some miracle recipe. Exposure blending is very useful but does have some limitations: it simply does not work with scenes containing moving objects. Also, when dealing with trees or grasses blowing in the wind, it can get tricky and sometimes even unworkable. That said, I find that exposure blending beats HDR programs by a long shot because the results are more realistic looking (personal choice here) and it avoids the muddy toned images that HDR programs often result in.

A first exposure, two stops underexposed to account for the brightness of the sky is blended with…

The Setup

So, what is exposure blending exactly? As its name suggests, it involves taking several exposures of the same subject and “mixing” them in Photoshop using layers and masks.  It is imperative that the framing be identical for each exposure, so it is important you use of a tripod, and ideally a remote release to minimize vibration and motion. The exact bracketing required varies from scene to scene and depends in great part on the dynamic range of your camera. Using my Nikon D700, I simply set it on “matrix metering” and take 3 exposures: 0, -1 and -2 stops. If you are just trying your hand at this, I would definitely recommend trying at least +2 to -2 brackets (5 images total), then adjust accordingly once you get more comfortable. Ultimately, however, only two exposures are usually necessary (0 and -2). I will sometimes blend in parts of a third one if I need more details in the shadows, but that is rarely required.

…a second exposure, which is metered for the brightness of the foreground.

Blending Exposures

Now on to the blending.

1)  Once the images are uploaded on the computer, process each exposure separately in RAW then open both exposures in Photoshop (here 0 and -2 stops).

2)  Go to the darker exposure, select all (command+A), copy (command+C) and paste it on top of the lighter image (command+V).

3)  Select the top layer (dark) and while pressing the alt button, click on the “add layer mask” button.  This will create a “see-through” mask that will come in handy later to “paint-in” details from the dark exposure onto the lighter one.

4)  In the layers panel, select the channels tab.  Photoshop allows you to create a selection based on the luminosity values in the image. In essence, at the click of a button you can select all the “light” pixels. You can do so by pressing the command button and simultaneously clicking on the RGB channel icon.

5)  You should now see a set of “marching ants”, indicating a selection appear on your image. While this can be used as your mask, I find that going one step further will provide an even better selection. To do so, press shift+option+command and click on the RGB channel icon one more time. This will intersect the previous selection with itself and select a narrower set of light values. You can repeat this as many times as you want, but I find that two selections (step 4+5 combined) are sufficient.

6)  Now move back to the “layers” tab and make sure to select the dark mask we created earlier in step 3, by clicking on it.

7)  Select the eraser (press E), select a large brush (400 px) with 0% hardness and ensure the opacity and flow are set at 100% (top panel). Make sure that black is your foreground colour (you can toggle between foreground and background colours by pressing X, if black is not already one of your colours, press D to revert to default colours, then press X to select black).

8)  Here is where the magic happens: simply start erasing over the overexposed portion of the image (sky and/or reflections for example). You will now see that the darker layer is literally being painted over the lighter one. Because the selection is completely self-feathering, you need not worry too much about being very precise with your painting. I usually find that a few passes with the eraser are necessary to bring all the colours out. Notice that while the sky is being uncovered, the areas in the shadows (e.g. buildings or foreground) are hardly touched.

9)  That is it. Once the result satisfies you, you can merge your two layers and continue on with your usual post processing routine.

10)  If you feel that you are still lacking a bit of detail in some of the shadow areas, you could use an overexposed frame (+1 or +2) to paint in the necessary detail. To do so, simply copy the overexposed frame on top of your other layers. Then, create a “see-through” mask as done in step 3. Select the Eraser, set the opacity between 25 and 40% and flow at about 50%, make sure your foreground colour is black. Then select the mask and start painting over your image in the areas where you would like to reveal more detail. Since the opacity of your eraser is low, multiple passes may be required to achieve the desired result.

The process may sound a bit daunting at first if you are not familiar with masks and layers but once you give it a go you will see that it is fairly straightforward and the results will surely speak for themselves!

To crop or not to crop?

Oh well, who cares?

If you thought I was going to start another one of those pseudo-religious wars, think again. If YOU want to start one of those, please refrain. Peace be with you. If you care to know, I love cropping. Crop. Crop. Crop and crop away!

Well, no. Not really. I am as much a believer in getting the shot in-camera as the next guy. Only, there is one problem. My camera only does 3×2…and I am a complete sucker for square and pano formats. I could go out there and get a 6×6 or x-pan camera, but frankly, I already own enough camera gear as it is. It gets heavy after a while. So what do I do? Yup, you guessed it: I crop, crop and crop away.

While I have indulged in the occasional 4×5 or 6×7 crops, I really mostly stick to square and pano formats. I wish I could say that all my crops were pre-visualised (and honestly, I can definitely say, that they are for the most part). The fact is, however, sometimes, you look at an image and it just doesn’t work in its original format. You crop away, and miraculously, it springs to life.

What are your favorite formats? What tickles your fancy? I would love to hear your opinions.

Moody Coast

So here I am playing catch-up with my keywording, yet I just can’t help myself but try and play around with some of my unprocessed shots (hours of keyword entry isn’t exactly my definition of fun!). As I mentioned in a recent post, I am also starting to discover Lightroom 2.5. The program doesn’t really do much for me, except for the cataloging and keywording functions which are quite a bit more advanced than bridge. In any case, some of the cool things in LR are the Black and white presets. This is a shot that dates back to almost two years ago, in the Olympic coast of Washington State in Northwestern US. It was quite a dark and grey evening, which made for some moody images of the legendary Ruby Beach. I thought the Selenium look worked quite well with this shot. I would love to hear your thoughts on this.

_YB22081 selenium

Balancing Act

After a week of non-technical posts, I am going to spend most of this week discussing, well, mostly technical aspects of photography (sorry Jenn, you know I just can’t resist it). Did you really expect anything different? I mean come on, I am a scientist, hardcore geek, a nerd. And for the record, I fully embrace my nerditude, so your efforts to deride it will be vain, ha! I also expect that someday geeks will rule the world, but I digress…


One of the most overlooked parameter in digital photography has to be White Balance (I mean with a name like that are you really surprised!). Most people simply set their camera to Auto WB and just leave it at that. In fact one of the main reasons I shoot in RAW is to have the flexibility to modify the WB in post-processing. Granted RAW gives you other things as well, but WB flexibility is high up on my list. Most of you already know this  (I actually found out there are people who read this blog, so I don’t have to pretend anymore, really pumped!), so I won’t dwell on this. Instead, I would like to focus on a little trick that makes WB even more invaluable. Read More »