Using RGB Auto Levels
by James Duncan Davidson
For example, I'm going to show you an aerial photograph I shot recently on a trip. This is how it looks in Aperture on import with no adjustments made to it:

7 Comments
Jim N. 2007-02-10 05:47:55 |
James, I stick with Luminance most of the time, and thought that Apple designed these shortcuts as one-or-the-other. I never considered using them together. So do you use Luminance and *then* RGB, or one or the other? Or do you only jump to RGB when there is a tricky color cast? |
James Duncan Davidson 2007-02-10 15:10:10 |
Indeed, the shortcuts are "one or the other". IE, when you hit the RGB version, it appears to relevel based on RGB values and doesn't take into account the previous leveling opearation. I use Luminance first and then, when there's still a cast that I want to get rid of, I'll try the RGB one. There have even been times where I've flipped back and forth trying to make up my mind before moving onto using other tools, such as the colors tool. |
Matt Swann 2007-02-10 18:18:09 |
Great tip. One thing I've noticed about the Auto Levels and RGB tools is that they tend to clip bright values -- that is, a properly-exposed photo (no blown-out highlights) will often end up with areas of overexposure after using the Auto tools.
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James Duncan Davidson 2007-02-12 19:43:15 |
Matt: Leveling tools typically "toe-in" just a bit into the histogram. The theory goes that the first bit of black is typically a bit noisy. I'm not sure what the idea is on the white side, but I know that there's gotta be a reason as so many of the auto tools tend to do it. Some applications let you set the amount of "toe-in", but I haven't seen this in Aperture. |
Matt Swann 2007-02-12 20:34:33 |
Thanks for the response, James!
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Jim N. 2007-02-13 05:07:42 |
The auto-exposure is a disaster at least 50% of the time for me. But often if I go Auto Exposure, Auto Levels it works out okay. Just this past weekend I got into the advanced tab of the highlights panel, which I found very productive --if not very time-consuming-- in dealing with blown highlights.
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PJ Harvey 2007-03-03 08:22:30 |
Auto levelling has been completely unusable for me since the beginning (Aperture 1.0) with my D70 and D200 pictures, example: http://homepage.hispeed.ch/kukushka/Levelling (however, I had figured out myself that RGB levelling, done manually, is one of the best ways to deal with colour casts in long range landscape photography, particularly these blue-ish shadows) |