I’m still post processing all the pictures from the Bonaire trip. For some, it’s merely a matter of looking at the sharpness of the picture, realizing that it will never be good, and rejecting it. (I’m at the stage of the game where I’m starting to look forward to those.) For the rest, it’s sometimes a matter of correcting the exposure, and for nearly all of them, correcting the color. My attitude is that even a mediocre picture should be corrected, since occasionally you’ll have a picture “come up” in a surprising way.
Part of the problem is my camera settings. I’m realizing after the fact that I was getting more of a mix of ambient light, (which is lacking in red) and strobe light than I realized. There were some times when I was trying to use mixed light, in order to get a colorful background, mostly I was looking for a straight strobe exposure. I was aware that they looked a little green on the camera screen, but they basically looked OK, so I let it go. In hindsight, I should have bumped up the strobe power a bit, and lowered the camera ISO.
So now I’m color correcting. Endlessly. My tool of choice is Apple’s Aperture 3. This version features a Curves adjustment, which often does a very good job. Previous versions, I’d try a Levels adjustment, which would sometimes work, but often not, and wind up using Photoshop’s Auto Levels which often does an amazing job, or Photoshop’s Curves, which I didn’t understand well back then. Photoshop is still my “nuclear option”, for cases I still can’t correct in Aperture, but there are far fewer of them.
The advantage of Aperture is that it doesn’t apply your adjustments to the picture and create a new picture, it saves the adjustments separately from the master photo, so they can be turned on or off, and take up much less disk space. They’re sort of like adjustment layers in Photoshop. When Aperture has to send a picture to another editor though, to preserve the master, it creates a duplicate master with your current adjustments and sends that to the other editor. This takes up more disk space. Photoshop’s Auto Levels still does a better job in some cases, but I find it’s Curves adjustment to be more fiddly than Aperture’s–less of a mouse move makes more of an adjustment.
So how does Curves work? For each color, you see a diagonal line over a histogram for that color, or over a histogram of the luminance. Pulling the line down curves it downward, and makes that part of the picture darker in that color; dragging it up increases that color. You can also adjust where the black and white points should be for that color. So for my underwater pictures, I’m typically adjusting the red white point more to the middle, since often there’s very little red, and then dragging the red curve upward a bit. This sometimes makes the shadows too red, so I adjust the red black point to compensate.
A lot of the pictures are lightish, so instead of increasing the red, I’ll decrease the green and blue instead. I usually start with the green, adjusting its black point and bellying the curve downward a bit, then I’ll go to the blue to finish off. Generally the blue takes less correction.
Some of the results are really good, but it’s all very tedious, and more clicky than it needs to be. You can set an auto gray point, but very few of the pictures actually have a gray in them. In addition, for each picture, you have to click to enable the Curves adjustment (I’ve added it to the default set), then choose a channel from a drop box. It would be nice if it just had buttons for the channels.
So far, I’ve gotten to Thursday’s pictures, and I haven’t added any metadata or assigned ratings yet. I still have to identify what I was shooting, and then I can start getting them online. I haven’t decided yet whether to post them within the blog, or have Aperture generate a site and link to that. The Aperture generated sites are very nice looking, and easy to do, but it would be good to have them here. Decisions, decisions.