Photo post-processing

This post is written mainly for those of my readership who aren’t photography nerds, though I’m sure the photography folk will appreciate seeing my work flow.  I’m going to show you how the image above is created from scratch, going from importing the photo right through the three pieces of software I use to process it.  By the end you’ll see just how much difference can be made by spending the time and effort on playing with photos after they’re taken (i.e. post-processing).  Knowing how all of this works also helps me to choose the settings in my camera to help with getting the best result during post-processing.


This is the first image that is taken, and it is completely unprocessed.  It has a few of problems.  First of all, the perspective is distorted by my wide-angle lens.  This won’t be readily apparent unless you compare with the corrected image a little further down the page (I’ll remind you to compare when you get there).  Secondly, the horizon is level but the building (which is quite vertical in real life) is leaning to the left.  Finally, cameras typically don’t have enough dynamic range (i.e. the ability to capture both very dark and very bright things at the same time) to capture a scene like this without losing the detail in the dark parts, the detail in the light parts, or both.



That’s where HDR (High Dynamic Range) bracketing comes in.  For this photo I set my camera to take three photos; one at normal exposure, one purposely too dark, and one purposely too bright.  If you look at the image that is too dark, you’ll see that it’s managed to make the sun look pretty good and capture all of its colour.  If you then look at the image that is too bright, most of the scene is ‘washed out’ but the shadows actually look pretty good.  In a later step I will use software to combine these three exposures to get the best of all three photos.


Now that I’ve imported the photos onto my computer, I can start work on them.  The photo above has had the perspective distortion corrected automatically in a piece of software called DxO Optics Pro.  In that same software, I used a tool to indicate that the building should be vertical and needs correcting.  This is done by drawing a line along the edge of the building, then drawing a second line to indicate which angle it should be at.

If you download this photo and the very first photo in the post, you’ll be able to compare back-to-back and see what a difference just correcting the distortion makes.  This correction was then copied and applied to all three of the HDR bracketed photos.


The next step is to merge the three exposures into a single photo using Photomatix Pro.  This software is pretty versatile in that it can mix them together (or any number of exposures, in fact) using a variety of different methods.  I use the method that gives the most natural results as I typically use HDR bracketing to capture a scene that the eye can see but the camera can’t adequately capture.

Look closely at the picture and you’ll see that the sun is now reduced in brightness and has more detail and colour.  You’ll also see that the shadow in the bottom right is now lighter and has more detail to the snow.  The results are subtle, but they make a big difference to the photo.


Now I can import the image into Adobe Lightroom and start playing with some sliders.  I quite like the 16×9 aspect ratio (i.e. the ratio of width to height is 16:9, much like a widescreen television), and I need to remove the black parts from the distortion correction process, so the first thing I do is crop the image to get the final composition.

Next I fiddle with some sliders.  These sliders include white balance (i.e. how ‘warm’ or ‘cold’ the image is), the contrast, the exposure, the amount of colour, etc.  I adjust this to make the image look on the screen how I remember seeing it in person.  Sometimes this is not a technically accurate representation of what was there.  A scene like this is coloured by what I was thinking and feeling at the time, and how awe-struck I was by this scene, so I’ve enhanced the colours to be a bit more than real because everything did seem unreal (and amazing) to me at the time.


The next thing I want to do is remove the cane from the photo as it distracts the eye from taking in the whole picture properly.  I do this by using the clone tool.  It does as it says; clones a small piece of the picture from one place to another.  Small piece by small piece, I clone patches of the snow from next to the cane and use them to cover it up.  Half way through the process look like this:


The trickiest part is actually removing the cane’s shadow as it’s a much larger area.  My patience is rewarded eventually, however, and the cane and its shadow are removed.


To see the subtle changes, compare this with the image just before I started using the crop tool.  No other changes were made so it makes an interesting comparison.


Last of all, I made a lot of very small and subtle changes to the sky to hide some of the effects left over by combining HDR bracketed photos.  If you look at an earlier image you’ll see that the sky next to the building is a bit darker than the rest of the sky, and it stands out once you notice it.  A few little tweaks later and it’s no longer as noticeable.  I also made several small, subtle changes to the sky to make it more even and stop it from drawing the eye away from the landscape.

The changes made the whole sky seem too bright though, so I added a gradient filter.  The gradient filter tool allowed me to draw a line across the photo, which is this case is a horizontal line along the top of the sun.  I reduced the exposure above that line just slightly, though everything underneath is untouched.  Compare the photos back to back if you want to see the difference.

The building was the final piece to be tweaked.  I used the brush tool to select the green outer shell of the building without affecting the windows.  I then made some changes to improve the contrast of the building and make it seem a little more green (because it is actually quite green, but my previous processing efforts had diminished that slightly).  Finally the photo is exported and ready for display.

This whole process took me around 1.5 hours.  Getting the right look is a matter of trial and error, and I find it often pays to reset it all and start again a couple of times, even once I get the result I’m after.  There is often more than one way to get to the desired result, and each different way will have different side-effects (that may or may not need to be fixed up later).  Compare the very first photo to this last one and I think you’ll agree that post-processing photos is effort well spent.




One Comment on “Photo post-processing

  1. Pingback: My Spare Time | Bob of the Cold

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