Intro to Photo Processing
It is important to commit the three simple rules of underwater photography to memory; get close, don’t shoot down and know when to shoot ambient or with a flash. With practice your execution of these techniques will improve, but every shot won’t be perfect. The subject may not always allow you to get as close as necessary for a very sharp image. Your composition might not have been as good as you would have liked and if you are using an external strobe you may become acquainted with backscatter.
There are a lot of tips and techniques specific to minimizing backscatter but for now the most important thing you can do is remember to get as close to your subject as possible. The less water column between your subject and your flash the fewer particles and bubbles there will be that create the reflections that cause backscatter.
Luckily, there are a lot of programs available for post-processing your photographs to help fix the little issues that cannot always be avoided. These applications can’t turn a terrible picture into a good one, but they can salvage a decent shot with a few imperfections. They can be very handy at making small tweaks to the color, brightness and contrast.
You might want to try a few different programs to determine which you prefer, some are free and some that aren’t will give you a trial period. Adobe Lightroom has a trial period so I gave it a shot but it wasn’t for me. It was very powerful and had more than enough capability but for the few subtle tweaks I typically do it was overkill. The other options I have tried are IrfanView, Picasa and Photoscape, all of which are free and have similar capabilities but with different interfaces. I prefer Photoscape and use it for all my post-processing.
The one capability that Photoscape doesn’t have is the ability to remove backscatter. You should always try minimizing it as much as possible when you are shooting but sometimes even with great care composing the shot and after some strategic cropping a little will remain. In these instances, I use Photoshop to fix what is left. Below are two examples starting with a raw shot and working to a finished product.
While diving the Bridge Rubble out of Destin with about 30 feet of visibility and moderate particulate, I spotted a blue angelfish beneath a ledge. I began slowly positioning myself for the shot. I would have liked to have gotten closer due to the particulate but the fish was starting to go further beneath the ledge and I didn’t want to press my luck. I got the shots I could and moved on to another subject.
The photo to the right is the raw shot downloaded from my camera including the imperfect composition and illuminated particles. Despite it’s imperfections, I liked the look of it peaking out of its hiding spot. So I went to work cropping it and making a few tweaks to the contrast and color. After making a few small adjustments in Photoscape what remained was the photo below and left.
At this point the illuminated particles are obvious and of course distracting. After a few minutes in Photoshop removing the biggest offenders the final product is shown on the right.
I would have preferred to have gotten closer without the angelfish slipping beneath the ledge and gotten a sharper image that needed less cropping and less particles to remove. But this shot provides an excellent example of how small imperfections can sometimes be corrected with a little post-processing.
The two biggest fixes for the first shot were cropping and removing the illuminated particles. The use of the strobe brought out the colors well in the original so only minor tweaks based on personal preference were needed in that regard.
While doing the shallow dive at Stingray City in Grand Cayman I took the following shot with ambient light only. My camera was in underwater mode which automatically does white balance adjustments and the shot was taken in only 12 feet of water.
Using ambient only with some white balance adjustments produced a pretty good shot without any post-processing. After spending just a few minutes in Photoscape though, I was able to bring the colors out a little more, up the contrast a bit and do a little bit of cropping to produce the end result on the right.
Typically a little editing will always be needed to produce a final photograph, but it is always better to try to produce a quality shot from the start. If you are shooting with ambient only, improvement to the colors in post might be needed. If you are shooting with strobes the colors may be vivid from the start but you might need to remove some backscatter.