Digital info for serious shooters: specializing in Nikon & Canon

Super-charging your Photoshop using LAB + Curvemeister

Are you ready to take your color correction & color enhancement tools to the next level? In this issue we'll follow up on our introduction to the LAB color space with some tips on how to get the most out of your images with LAB by using Curves and Curvemeister. Also, we're pleased to announce that our African photo safaris for 2006 are ready for sign-up. They are the best digital photo trips you can find for African wildlife and will be a lot of fun. We'll also give you a heads up on some hot new products including a great new value in printer profiling solutions, a slick GPS for your camera and Nikon's new Macro flash system.

Details on our 2006 Africa Digital Photo Safaris

Why Edit in LAB?

I've written previously about using the LAB color space to do color and tone correction in Photoshop. Every day I'm more impressed by what is possible using LAB.Because the LAB colorspace separates the Luminance ("Brightness") of your image from the color components it makes it possible to quickly operate on just the color or just the tone of your images. Anyone seriously interested in maximizing their Photoshop skills should get Dan Margulis's book on the subject: Photoshop LAB Color but in this issue we'll give you some quick ideas to get you started and a pointer to a great plug-in that will make your job much easier.

One of the biggest tools to use in LAB is Curves. Instead of Red, Green, and Blue, LAB Curves are L-Lightness, a--Red/Green and b--Blue/Yellow. Simple moves in the a or b channel Cuves can quickly enhance specific colors in specific directions. Similarly the L Curve only affects the tone of the image without altering the color content.


Taming LAB with Curvemeister

As powerful as LAB is, using it does have one big problem--it creates a painful workflow because you need to convert to LAB, do your corrections, and then (typically after flattening) convert back to RGB (or to CMYK). Layers and their intent are lost and you spend a lot of time converting back and forth. Fortunately, after having written about this problem one of our readers, Mike Russell, the genius behind a very cool tool called CurveMeister, contacted me and explained that with CurveMeister you can use LAB curves right from RGB in Photoshop. This is incredibly helpful and saves tons of time..

Curveveister saves as much as minutes per image just because of this one feature. But it is packed full with lots of other productivity enhancements that make Curves--the most powerful command in Photoshop--much easier and faster to use. First, it offers a great large preview screen of your changes, which you can easily set to any channel. Second, it color codes the curves dialogs so that (for example) you can easily remember which end of the a & b channels are red, green, yellow or blue. Third, it provides a much larger and nicer window for actually manipulating the curves. Fourth, it has the ability to use or create "pushpins" which are memorized colors. Assigning a push-pin to a place in a photo pins that spot to a particular color. Finally, it is chock ful of other settings such as history that allow you to take Curves way beyond what is possible with Photoshop.

 CB Dan Margulis, color correction guru and author of some of the best books on Photoshop color correction, has written a new book on using the LAB colorspace for color correction. My copy is on the way and I'll be doing a more complete review, but it is such a unique idea and has received so much good feedback that I wanted to give you a heads up. You can buy the book online.

Part of my enthusiam for Curvemeister is necessity. I'm in the middle of creating a fairly large exhibition requiring over 40 large format prints. I want to have them all "match" so I've been reprocessing my existing TIFFs to maximize what I can get out of them and optimize them for the size and type of paper I'll be using. Of course this is a lot of work since I want to do each one by hand and check the results. The first thing I noticed is that for 2 out of 3 I could improve the color and the drama of the image using LAB. The second thing I realized is that it would take me days to do that fully manually. Curvemeister enables me to fairly quickly add a LAB curves layer to my existing images, preserving much of the rest of my work, and then quickly proceed to the final resizing, sharpening, and printing with ImagePrint.

Quick Color Enhancement using Curvemeister & LAB

You really need to read Dan's new book on using the LAB colorspace to get the most out of LAB, but just to give you a taste of what is possible here is one of my quick "cookbook" approaches to enhancing the color in a digital capture, based on advice in Dan's book:


Curvemeister can be used to enhance color with a simple 
LAB curve without switching to and from the LAB colorspace

Quick Color Enhancement using Curves & LAB:

  1. Make a copy of your background layer (CurveMeister can't be used as an adjustment layer. It will overwrite the top layer of your image, so you probably want to make sure it is a copy)
  2. Bring up CurveMeister and swtich it to LAB mode.
  3. Create some steep angles in the "a" (Red/Green) and "b" (Blue/Yellow) channels. See the attached screenshot for an example. Controlling the angle and shape of the two "curves" is the key to getting the best out of this technique, so feel free to experiment and/or read Dan's book.
  4. Your image will probably look quite gaudy now, but don't worry about that. Go ahead and Apply the Curve and then use the Opacity slider to control the effect. Back it down until you get the enhancement you want without your image looking un-real or too gaudy.

Correction or Enhancement: Where is the line?

Many discussions of photo-editing center on a debate about what changes are "permissible" to an image. Obviously a lot depends on the usage, but there is certainly some energy about determining which edits are "correcting" the image back to the "real scene" versus enhancing it beyond that. Frankly, the line is incredibly murky. Every person sees each scene differently, and the same is true for cameras. Working with our raw captures (whether they are film negatives or digital originals) is a time honored practice. The only difference is that we have increasingly powerful tools. The only guideline I have is a simple one: If you correct, edit or otherwise tweak an image until it looks "better" than the viewer imagines a "photograph" can, it will be judged in their mind as an artwork, rather than a pure photograph. That can set the bar quite high for how compelling it needs to be. But if you leave the image mostly alone then the viewer will tend to credit your photographic "craft" and think of the image as a photograph and judge it accordingly. So as you start to work on an image, think about what you want it to convey and who the audience is. Let me know your thoughts on this in our Digital Cafe forum














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