To help you make sense of the most recent episode of dekePod, I’ve written up a discussion of how I modified the colors of my backyard in the Lab mode. Although it flies by in the video, the technique is not particularly difficult. I don’t use Curves or masking or anything terribly complicated. Just Levels and — brace yourself — Brightness/Contrast. In Photoshop CS3, Brightness/Contrast has not only turned into a respectable command, but it has been elevated to pro status when combined with Lab. And it remains as easy as ever to use.
Some portions of this article have been excerpted from my upcoming article, “Don’t Fear the Lab Mode,” which will run in the September, 2008 issue of Photoshop User magazine. So as not to diminish the impact of that article (as well as the two that will follow it), I have purposely made the steps here brief, illustrated with thumbnail-resolution imagery. You should still be able to follow along, but you’ll have lots more to look forward to in Photoshop User.
Step one: Open an image
One that needs help. I reckon this low-contrast photo of my backyard qualifies. There’s even a smudge on the window and twigs in the way. Gosh I’m good.
Step two: Switch to Lab
Choose Image > Mode > Lab Color. The result is an image with three channels: Lightness, a, and b. Lightness conveys luminance. As diagrammed below, a controls tint and b controls temperature.
Step three: Fix a and b with Levels
Add a Levels adjustment layer. Skip Lightness and switch to the a channel. Apply symmetrical adjustments to increase color contrast and boost saturation. I raised the black point to 8 and reduced the white point to 175 (255 minus 80). Next go to the b channel and repeat the process.
Step four: Tweak the values
My photograph suffers from a slight bluish color cast. To compensate, I reduced the white point in the b channel to 172. A little lavender remained, so I went to the a channel and increased the black point to 81. Click OK.
Step five: Blend away any aberrant colors
The reds and oranges in the wood and bricks are too hot. To pull them back, I right-clicked on the Levels layer and chose Blending Options. I chose a from the Blend If pop-up menu and dragged the white point for This Layer to 150. Then I pressed Alt (or Option) and dragged the right half of the white point to 210. I repeated the process for the b channel and clicked OK.
Step six: Apply Brightness/Contrast
To address the Lightness channel, add a Brightness/Contrast adjustment layer. I went with Brightness and Contrast values of +20 and +40, respectively, to achieve the more cheerful image below. Click OK to apply.
What makes Brightness/Contrast so well suited to Lab? It invariably affects just the Lightness channel; it can’t even see the contents of a or b. Plus, its controls have been dramatically improved in Photoshop CS3 so the command no longer clips shadows or highlights.
If you compare the first image to the last, you’ll see that we’ve made a lot of progress. But our work is not done. In future editions of my regular Deke Space column for Photoshop User magazine, I’ll show you how to sharpen the image using smart filters, smooth away color noise, and resolve chromatic aberrations by working within Lab and around it. Finally, we’ll apply a panoramic crop to achieve the result pictured below. It all takes us into more advanced territory, but the results justify the effort.
You can also learn about this technique in my video series Photoshop CS3 Mastering Lab Color, available from lynda.com. Specifically, check out the 11-movie Chapter 3, “A Typical, Nondestructive Lab Correction” which takes this image from its wretched beginning all the way to its panoramic end.