[...]... and cyan, green and magenta, and blue and yellow The LAB channels, bottom row, are decidedly different LAB by the Numbers Photoshop LAB Color: The Canyon Conundrum Copyright ©2006 Dan Margulis Three Pairs of Channels At top right is the composite color image of this flower There are identical-looking versions in all three of the colorspaces that Photoshop fully supports The ten channels are arranged... object and the leaves, just barely, as dark ones in the A channel In the B channel’s opponent-color scheme, 25 Chapter 2 26 B C D E F Photoshop LAB Color: The Canyon Conundrum Copyright ©2006 Dan Margulis A Photoshop LAB Color: The Canyon Conundrum Copyright ©2006 Dan Margulis LAB by the Numbers light grays represent yellowness, dark grays are blue, and a 50% gray is neither Inasmuch as nothing in this picture... L curves won’t work And that’s the basic LAB correction, minus explanations of why LAB works or how it’s structured If you want that now, skip ahead to Chapter 2 If instead you’d like a more technical explanation of why we like color variation and why the best way to get it is in LAB, keep going, remembering that the second halves of chapters assume much more Photoshop knowledge than the first halves... create color variation Below, Figure 1.15B is applied to the original at 18% opacity (inset) B achieved without LAB s ability to drive certain occurrences of a given color toward red and others toward green-blue (cyan), there’s a small problem If only LAB can produce Figure 1.15B, then only LAB can produce Figure 1.16B, which is Figure 1.15B applied to the original image at 18% opacity And Figure 1.16B... in that RGB and CMYK are exceedingly similar If you know how to work in one, you already know how to work in the other The one that’s really different is LAB, as Figure 2.1 demonstrates 24 Chapter 2 Green Blue Cyan Magenta Yellow L A B Photoshop LAB Color: The Canyon Conundrum Copyright ©2006 Dan Margulis Red Black Figure 2.1 Top right, the original picture of a pink rose Top row, in order: the RGB... going, remembering that the second halves of chapters assume much more Photoshop knowledge than the first halves do And a final reminder, once you’re done with your LAB maneuvering: few output devices accept LAB files, and few programs outside of Photoshop will display them So, convert the file back to RGB, if you’re going to post it on the Web or send it to a desktop or other printer that requires RGB; or... convenience that your default RGB working space is sRGB If it isn’t, you can use Edit: Convert to Profile (Photoshop CS2; Image: Mode>Convert to Profile in Photoshop 6–CS) to move the file into sRGB And once you have an sRGB file, you can Edit: Assign Profile>Adobe RGB (Image: Mode>Assign Profile in Photoshop 6–CS) for a significant boost in color, or (as in Figure 1.12C) assign Wide Gamut RGB for an even... channels have equal values Many, many points would have to be compared channel-to-channel to be sure that the values were approximately equal in all three, regardless of the darkness In LAB there is no such problem The A Photoshop LAB Color: The Canyon Conundrum Copyright ©2006 Dan Margulis blue, side of green Notice how Figure 2.2E’s grass seems bluer than that of the original, Figure 2.2A This is not because... point If the LAB file contains colors that the destination space can’t reproduce, it takes a fair amount of experience to predict what will happen The ability to create such colors is one of the big dangers—and big opportunities—of LAB In the “Closer Look” section of this chapter, we’ll dig deeper, but for now, we need to be careful when dealing with colors that exist in the warped world of LAB only In... colors that exist in the warped world of LAB only In Chapter 1, we worked on canyon after canyon, having learned that canyons are a specialty of LAB At this point, you should understand why First, canyons have very subtle color differentiations that cameras Photoshop LAB Color: The Canyon Conundrum Copyright ©2006 Dan Margulis that measured around 60L(15)A15B Can you name what it was? The 60L suggests something . version. They call it CIELAB or L*a*b*, both of which are a pain to pronounce and maddening typographically. Photoshop calls it Lab color,” but the name has nothing to do with a laboratory: the L stands. to illustrate the power of LAB correction (bottom). 1 Chapter 1. The Canyon Conundrum Page 2 Return to Table of Contents Chapter 1. The Canyon Conundrum Photoshop Lab Color: The Canyon Conundrum:. in Utah. My book Professional Photoshop goes around 100 miles to the south with a shot from Canyon- lands National Park. Another Photoshop book illustrates its LAB section with a shot from Bryce