Photoshop Lab Color- P6 doc

Color instead of Normal. That restores the original detail while retaining the color created by the curves. • Step Three: Now we’re in LAB . You already know the drill here. • There’s little need to discuss Step Four, which is going to be a cleanup operation to make any final adjustments. Two possible variations depend upon whether Step Four is a CMYK or RGB step. If it’s CMYK , then during Step Three I’ll consider where the sharpening, if any, should be done. Generally, if the image is dominated by a single color, I’ll go the CMYK route, if not, the L . And if Step Four is an RGB step, then I sharpen the L for sure. Also, if Step Four is CMYK and the shadow is currently too light, I won’t fix it in LAB , because it’s so much easier to adjust in the black channel of CMYK .If Step Four is RGB , then I don’t much care where the shadow gets adjusted. By the Numbers and by the Instinct Before closing out the chapter, and with it the first half of the book, we should look at three specialized maneuvers. Two, as promised earlier, are for those people who are under such pressure to get images out quickly that they need to adopt an all- LAB workflow, never mind that they could get better pictures if they had more time. The other involves a duplicate layer like the theoretical one we just constructed in RGB to prevent the clouds from getting too blue. A lot of color work depends on doing things “by the numbers,” starting with white point and black point. The last example we discussed, a curve that was designed to make the edges of a hypothetical cloud less blue, was also a “by the numbers” correction. Ex- perienced folk would understand the assign- ment to be “make the blue parts of the cloud more neutral.” They would know that, in RGB , neutral colors occur when all three channels have equal numbers. They would also know that an overly blue cloud means that the red channel is too dark, or the blue channel too light, or both. So they would try to equalize the two values, or get as close as they could without massacring the rest of the image. On the other hand, some of what we do comes under the heading of wild guesses. We know that the canyon images of Chapter 1 should be more colorful than they were orig- inally, but we don’t know how much. We agree that Figure 7.6A is too dark, but we may not agree as to whether the proposed corrections went too far in battling said darkness, or not far enough. There’s nothing “by the numbers” about that determination. In such situations, where there is no right but there is a wrong, and where we are just experimenting to try to get something more pleasing, layering obviously excessive corrections on top of one another becomes attractive, particularly when short of time. There’s nothing overtly wrong with the numbers in Figure 7.9A, so you could con- ceivably vote for it as the best one of the four versions on the next two pages. Personally, I find it third best, because the dark areas in the animal’s head and body are plugging, and because there isn’t enough color variation. If it were only as easy to cure brucellosis as these problems, herds of bison might again be roaming the American west. The indicated medication here is S / H ,followed by a dose of steepened AB .But the question is, how much to prescribe? When to Go Too Far As we saw earlier, Shadow/Highlight is more effective in the L channel than it is in RGB , particularly when there aren’t any bright blues or reds to cause trouble. After converting the image into LAB ,I activated the L channel and chose S / H shadow values of 50% Amount, 25% Tonal Range, 12 Radius, reaching Figure 7.9B. Summing Up: LAB and the Workflow 151 Chapter 7. Summing Up: LAB and the Workflow Page 17 Return to Table of Contents Chapter 7. Summing Up: LAB and the Workflow Photoshop Lab Color: The Canyon Conundrum: And Other Adventures in The Most Powerful Colorspace By DAN MARGULIS ISBN: 0321356780 Publisher: Peachpit Press Prepared for Kanchana Karannagoda, Safari ID: kanchana@ceybank.com Print Publication Date: 2005/08/08 User number: 910769 Copyright 2007, Safari Books Online, LLC. This PDF is exclusively for your use in accordance with the Safari Terms of Service. No part of it may be reproduced or transmitted in any form by any means without the prior written permission for reprints and excerpts from the publisher. Redistribution or other use that violates the fair use priviledge under U.S. copyright laws (see 17 USC107) or that otherwise violates the Safari Terms of Service is strictly prohibited. I then tried Layer: New Ad- justment Layer>Curves. An adjustment layer maximizes flexi- bility. It encompasses a single command (in this case, curves) but that command can be modified at any time before the image gets flattened for output. Moreover, as with all layers, its opacity can be changed at any time if we feel that the effect is too strong. The effect of Figure 7.10B is too strong. The AB curves are so incredibly steep that parts of the animal became brilliant red and other parts that were origi- nally of a similar color became blue. The result lacks contrast almost completely, because nearly the entire LAB file now consists of imaginary colors: greens, blues, and reds too brilliant for any form of reproduc- tion. So, Photoshop lightened everything in a doomed effort to match the intensity. By lowering the adjustment layer’s opacity to a minuscule 6%, I was able to bring those wild colors back into gamut and get what I wanted, more or less, in Figure 7.10A. Or, to put it another way: the curves of Figure Figure 7.9 The original, top, needs increased shadow detail, provided at center by an application of the Shadow/Highlight command. To establish color variation, the extreme curves at bottom were put on an adjustment layer before proceeding. A B Chapter 7. Summing Up: LAB and the Workflow Page 18 Return to Table of Contents Chapter 7. Summing Up: LAB and the Workflow Photoshop Lab Color: The Canyon Conundrum: And Other Adventures in The Most Powerful Colorspace By DAN MARGULIS ISBN: 0321356780 Publisher: Peachpit Press Prepared for Kanchana Karannagoda, Safari ID: kanchana@ceybank.com Print Publication Date: 2005/08/08 User number: 910769 Copyright 2007, Safari Books Online, LLC. This PDF is exclusively for your use in accordance with the Safari Terms of Service. No part of it may be reproduced or transmitted in any form by any means without the prior written permission for reprints and excerpts from the publisher. Redistribution or other use that violates the fair use priviledge under U.S. copyright laws (see 17 USC107) or that otherwise violates the Safari Terms of Service is strictly prohibited. 7.9 were terrific, but 16.67 times too much of a good thing. Having a layer go a little bit too far is eminently sensible. You can always cut the opacity if it’s too much. But 100% opacity is as far as the slider goes. If the layer hasn’t gone far enough, you have to begin again. Making the layer 16.67 times too extreme is overkill. My first Shadow/Highlight move was also questionable, for the opposite reason. As the Figure 7.10B inset shows, I put that correction on its own duplicate layer, so the final document actually had three layers: original on bottom, S / H layer in the middle, and the weirdly colored layer on top. Its opacity is only 6%, but the middle layer is at 100%. There’s something to be said for a stronger correction on the middle layer, on the theory that if we don’t like it, we can always dial down the opacity setting, whereas if we think it’s not enough, we’ll be put to needless extra work. The Partial Cast and Its Cure The final piece of the one- minute workflow puzzle con- nects two types of images that have large partial casts. The less common variety is biased toward different colors in its dark and light areas. The more common one is usually caused by overzealous autocorrection routines on digicams. It consists of beau- tifully neutral white and/or black points hitched to images with painfully bad color in the midrange. Such images can usually be made to look just as good as if the lighting had been normal, provided you’re highly skilled and have 15 minutes or so. LAB is usually not the first step in that case. Instead, we start with some Summing Up: LAB and the Workflow 153 Figure 7.10 Top, the final version is loosely based on the bottom version, which was produced by the curves of Figure 7.9 applied on an adjustment layer. Inset, the Layers palette sets the opacity to a very low number. A B Chapter 7. Summing Up: LAB and the Workflow Page 19 Return to Table of Contents Chapter 7. Summing Up: LAB and the Workflow Photoshop Lab Color: The Canyon Conundrum: And Other Adventures in The Most Powerful Colorspace By DAN MARGULIS ISBN: 0321356780 Publisher: Peachpit Press Prepared for Kanchana Karannagoda, Safari ID: kanchana@ceybank.com Print Publication Date: 2005/08/08 User number: 910769 Copyright 2007, Safari Books Online, LLC. This PDF is exclusively for your use in accordance with the Safari Terms of Service. No part of it may be reproduced or transmitted in any form by any means without the prior written permission for reprints and excerpts from the publisher. Redistribution or other use that violates the fair use priviledge under U.S. copyright laws (see 17 USC107) or that otherwise violates the Safari Terms of Service is strictly prohibited. sort of cast-minimizing channel blending in RGB . But that takes time, and we’re talking about workflows where we don’t have much. So, the question is, how do we get the biggest impact as quickly as possible? LAB , being capable of huge color moves (see, for example, Figure 7.10B), is the likely choice. The problem is that AB curves can only drive the entire picture in a single direction, unlike RGB or CMYK , where curves can affect the highlights in one way and the shadows in another. The solution requires a selection, usually based on the luminosity of the image. It sounds harder than it is—it requires only a single keystroke and thus doesn’t knock us past our one-minute deadline. Our first opponent is a live image from a newspaper. There- fore, it’s quite relevant—in news- papers, a minute to fix an image isn’t an uncommon demand. They don’t hold up the pressrun if your curves aren’t finished. As a formality, we examine the numbers and verify what we already know, that Figure 7.11A has a major-league yellow cast. The 154 Chapter 7 Figure 7.11 The original, top, has a strong yellow cast in its light areas, but the dark half is almost unaffected. Applying curves that neutralize the yellow in the highlights (left) creates a strange-looking dark half of the picture (center). A B Chapter 7. Summing Up: LAB and the Workflow Page 20 Return to Table of Contents Chapter 7. Summing Up: LAB and the Workflow Photoshop Lab Color: The Canyon Conundrum: And Other Adventures in The Most Powerful Colorspace By DAN MARGULIS ISBN: 0321356780 Publisher: Peachpit Press Prepared for Kanchana Karannagoda, Safari ID: kanchana@ceybank.com Print Publication Date: 2005/08/08 User number: 910769 Copyright 2007, Safari Books Online, LLC. This PDF is exclusively for your use in accordance with the Safari Terms of Service. No part of it may be reproduced or transmitted in any form by any means without the prior written permission for reprints and excerpts from the publisher. Redistribution or other use that violates the fair use priviledge under U.S. copyright laws (see 17 USC107) or that otherwise violates the Safari Terms of Service is strictly prohibited. pile of papers in the right foreground averages an eye-popping 95 L (4) A 43 B . However, as the image gets darker, the cast goes away. The man’s face is 49 L 24 A 53 B . That’s still too yellow, but not nearly as bad. If the paper is a pure white, the A and B values should be equal, but they’re 47 points apart. A face is typically slightly higher in the B , and here it’s 29 points higher. In the dark wood framing of the win- dows, the yellow’s not out of whack at all: 8 L 9 A 10 B , a bit to the yellow side of red, just as you’d expect. For objects darker still, we have to ignore the man’s jacket and tie, which for all we know could be blue. But the woman’s hair can’t be blue, and it comes in at 4 L 1 A 3 B . The B curve shown in Figure 7.11 sweeps away the yellow cast in the paper as easily as we might brush away an insect. Unfortu- nately, the darker parts of Figure 7.11B be- come too blue. The papers may be white, but the faces are purple. Avoiding this takes only a second. Starting with a fresh copy of the original, the same curves got me to Figure 7.12, except that before applying them, I hit Command- Option–1. Yes, we can get better results than this if we have a lot more time. No, Image: Adjustments>Auto Color isn’t an option; it chokes on this type of image so revoltingly that I refuse to waste space on it; even Figure 7.11B is much better. The Minute Waltz at the Masked Ball What we just saw was an application of a luminosity mask, or, more precisely stated, a luminosity selection. As most readers know, Photoshop allows us to select certain areas of a file, locking off all other areas so that they can’t change. In its simplest form, the selection divides the image into two completely separate parts. For example, if the area you want to select is very distinct from its surrounding, as the pink flower is in Figure 7.5, you can click it with Photoshop’s magic wand tool, establishing a selection. If you now hit the Delete key, the flower will vanish from the scene, leaving a hard edge as though someone had cut it out with scissors. It’s also possible to have something partially selected, meaning that anything we do to it will have less impact than it does on something fully selected. For example, we could Select: Feather the flower before deleting it. The edge of the vanished flower would then be softer, because it was partially selected and therefore only partially deleted, as opposed to the flower itself, which was fully selected and therefore would be on its way to pixel purgatory. A selection can be saved as a separate non- printing (sometimes called alpha) channel, or as a distinct grayscale document. We can Summing Up: LAB and the Workflow 155 Figure 7.12 This version uses the curves of Figure 7.11, but applies it through a luminosity mask that makes the impact of the correction pro- gressively less as the image gets darker. Chapter 7. Summing Up: LAB and the Workflow Page 21 Return to Table of Contents Chapter 7. Summing Up: LAB and the Workflow Photoshop Lab Color: The Canyon Conundrum: And Other Adventures in The Most Powerful Colorspace By DAN MARGULIS ISBN: 0321356780 Publisher: Peachpit Press Prepared for Kanchana Karannagoda, Safari ID: kanchana@ceybank.com Print Publication Date: 2005/08/08 User number: 910769 Copyright 2007, Safari Books Online, LLC. This PDF is exclusively for your use in accordance with the Safari Terms of Service. No part of it may be reproduced or transmitted in any form by any means without the prior written permission for reprints and excerpts from the publisher. Redistribution or other use that violates the fair use priviledge under U.S. copyright laws (see 17 USC107) or that otherwise violates the Safari Terms of Service is strictly prohibited. use the term mask to describe either one: something that can be turned into an active selection, by means of Select: Load Selection. White areas of the mask fully select the corresponding areas of the image; black areas don’t select at all. Grays represent partial selections: the darker the gray, the less the selection. In retoucher heaven, all objects of interest are as easy to select as a pink flower on a green background. In real life, the devil, who never sleeps, arranges for us to get stuff, particularly when a deadline looms, that’s about as easy to extract from its background as a beefsteak is from a hungry lion. Knowledge of LAB is a huge help in mask construction. In fact, it often eliminates the need for masks in the first place, as we’ll see in Chapters 10, 12, and 15. Still, there’s no denying that we frequently have to save complicated selections as masks. Often enough our first try at a mask isn’t perfect, and we need to retouch it just as if it were a picture in its own right. We can then load the finished mask as a new selection. In a one-minute, all- LAB workflow, we don’t have any time to save masks, let alone edit them. Fortunately, Photoshop has one already made for us, take it or leave it. We can load an existing channel as a selection, just as if it were an existing mask channel. The long way to do it is to open the Channels palette and Option–click the appropriate channel. The keyboard shortcut is Command-Option–1 for the first channel, and so on. In my LAB file, a Command- Option–1 loaded the L . There’s a huge difference between selecting the L , which would make the A and B un- available, and loading the L as a selection. That’s why many people use the phrase luminosity mask to describe it. When the L is loaded as a selection, the lightest parts of the image, the papers, are 156 Chapter 7 Review and Exercises ✓In Figure 7.5, what would have happened if the bottom half of the A curve had not been locked in position with extra holding points? ✓If you are using the Shadow/Highlight command to lighten an overly dark image in LAB , what type of object may be damaged? ✓What is the normal purpose of loading a channel as a selection? ✓Why is it dangerous to decide whether an image is neutrally correct based only on reading values for the light and dark points? (Hint: this is a much bigger problem in the age of digital photog- raphy than it used to be.) ✓Experiment with sharpening two of your own images. One can be anything where the interest object isn’t especially light; the other, if possible, a picture of a person with dark hair. Make three LAB copies of each for comparison (or start with three duplicate layers). On one, sharpen the L channel a bit more than you think is appropriate. Then try the same sharpening settings on the second version, but before applying them, load an inverted luminosity mask (Command- Option–1, followed by Shift-Command–I). This result will presumably look better. Now go to the third original, and see how close you can get to the second without using any mask. Chapter 7. Summing Up: LAB and the Workflow Page 22 Return to Table of Contents Chapter 7. Summing Up: LAB and the Workflow Photoshop Lab Color: The Canyon Conundrum: And Other Adventures in The Most Powerful Colorspace By DAN MARGULIS ISBN: 0321356780 Publisher: Peachpit Press Prepared for Kanchana Karannagoda, Safari ID: kanchana@ceybank.com Print Publication Date: 2005/08/08 User number: 910769 Copyright 2007, Safari Books Online, LLC. This PDF is exclusively for your use in accordance with the Safari Terms of Service. No part of it may be reproduced or transmitted in any form by any means without the prior written permission for reprints and excerpts from the publisher. Redistribution or other use that violates the fair use priviledge under U.S. copyright laws (see 17 USC107) or that otherwise violates the Safari Terms of Service is strictly prohibited. almost fully selected. The darkest areas, such as the man’s jacket, are hardly selected at all; and areas of intermediate darkness, such as the faces, are partially selected. That’s the secret of Figure 7.12. The full fury of the yellow-busting B curve is felt in the papers that are in our face in the foreground. The faces are made less yellow, too, but thanks to the luminosity mask, the effect is only about half what it is in the papers. The faces are therefore neither too yellow, as they are in Figure 7.11A, nor insufficiently yellow, as in Figure 7.11B. Before leaving this topic, we should discuss two other keyboard shortcuts. First, we sometimes need an inverted luminosity mask. Fig- ure 7.11A was a disaster area in the highlights but not bad in the shadows. Sometimes we get the reverse. A common situation is to find excessively neutral dark areas, particularly in forests, which want to be slightly green, while the remainder of the image is fine. To attack the shadows only, Command- Option–1 to load the luminosity mask, and Shift-Command–I to invert the selection, making darker areas more fully selected than lighter ones. That second keystroke is a shortcut for Select: Invert Selection. Also, remember Command–D, short for Select: Deselect. You have to do this after finishing your mask move; otherwise the selection will remain active indefinitely. I always forget this step. An Up-to-the-Minute Use of Layers There remains only the case where both the highlights and shadows are correct, but the rest of the image is messed up. Images of this description are a common occurrence in the age of “intelligent” digital cameras. We can’t correct them through luminosity masks, because the problem is at the center of the image, not the ends. In the mixed-lighting horror of Figure 7.13A, the light area in the second window from the right reads 99 L (1) A 4 B . I’d rather not have to measure a light source, and I’d rather than the A not be negative at all, but still the values are reasonable. Similarly, the darkest point, the side of the desk facing us at bottom left, is acceptable at 8 L 0 A 5 B . Note that we don’t measure the dark tiles. The corrected versions prove that not all of them are black. We don’t need any numbers to tell us that the rest of the picture is way too yellow and also too dark, just as Figure 7.11A was. And, as with Figure 7.11A, we can come up with LAB curves that slice through the yellow cast, only to get a disappointing result, which, in turn, is so vastly better than the mono- chromous mud produced by Auto Color that it’s not worth the space to compare them. But at least in Figure 7.11B, the highlights, the papers, were correct. In Figure 7.13B all the light areas have turned blue. So this time, instead of a selection that gets weaker as the picture gets darker, we need one that’s strong in the middle and weak at the ends. Constructing a strong-in-the-middle mask can be done but it isn’t easy. The more logical way is to use Photoshop’s most underrated selection tool, layer Blending Options. To proceed, the correction must be on its own layer. We can either duplicate the background layer and apply the curves to that, or, more economically, Layer: Add Adjustment Layer>Curves. Either way we wind up with, in effect, Figure 7.13A as the bottom layer and Figure 7.13B as the top. If the palette isn’t open, we open it now with Window: Layers. Now, we click and hold on its top right arrow, which brings up several choices including Blending Options, which is a subscreen of the Layer Style dialog. Or, we can get the Layer Style dialog directly by double-clicking the top layer’s icon. At the default layering settings of Normal mode, 100% opacity, the bottom layer isn’t seen at all. If we choose a different mode or change the opacity, the bottom layer can play Summing Up: LAB and the Workflow 157 Chapter 7. Summing Up: LAB and the Workflow Page 23 Return to Table of Contents Chapter 7. Summing Up: LAB and the Workflow Photoshop Lab Color: The Canyon Conundrum: And Other Adventures in The Most Powerful Colorspace By DAN MARGULIS ISBN: 0321356780 Publisher: Peachpit Press Prepared for Kanchana Karannagoda, Safari ID: kanchana@ceybank.com Print Publication Date: 2005/08/08 User number: 910769 Copyright 2007, Safari Books Online, LLC. This PDF is exclusively for your use in accordance with the Safari Terms of Service. No part of it may be reproduced or transmitted in any form by any means without the prior written permission for reprints and excerpts from the publisher. Redistribution or other use that violates the fair use priviledge under U.S. copyright laws (see 17 USC107) or that otherwise violates the Safari Terms of Service is strictly prohibited. a role. In Chapter 5, we discussed Luminosity mode, which uses the detail from the top layer and the color from the bottom. Or, in Nor- mal mode, an 80% opacity gives us a blended version, an 80-20 mix of the two layers. We can also exclude certain areas of the top layer by constructing a layer mask—or we can do it mathe- matically, by describing the areas we don’t want to use. That’s the function of the Blend If sliders at bottom right of Figure 7.14, which shows the two sets of L (Lightness) sliders. Similar sets exist for A and B , and they’re excruciat- ingly powerful, as Chapter 9 will show. For this image, however, we only need the L . By default, all sliders start at their endpoints, instructing Photoshop to use the top layer in all circumstances. But when the sliders are moved in, they impose limits. The settings in Figure 7.14 say, use the top layer, unless either the top layer is very dark or the bottom layer is very light. Observe that the sliders have also been split in half; we do this by Option–clicking as we move them. Between the two half-sliders is an area of transition, an area in which Photoshop is to blend the two 158 Chapter 7 Figure 7.13 Another yellow cast in the original, and another set of curves to kill it. But the highlights in the top version were correct, so although the bottom version eliminates most of the cast, all the light sources have turned blue. A B Chapter 7. Summing Up: LAB and the Workflow Page 24 Return to Table of Contents Chapter 7. Summing Up: LAB and the Workflow Photoshop Lab Color: The Canyon Conundrum: And Other Adventures in The Most Powerful Colorspace By DAN MARGULIS ISBN: 0321356780 Publisher: Peachpit Press Prepared for Kanchana Karannagoda, Safari ID: kanchana@ceybank.com Print Publication Date: 2005/08/08 User number: 910769 Copyright 2007, Safari Books Online, LLC. This PDF is exclusively for your use in accordance with the Safari Terms of Service. No part of it may be reproduced or transmitted in any form by any means without the prior written permission for reprints and excerpts from the publisher. Redistribution or other use that violates the fair use priviledge under U.S. copyright laws (see 17 USC107) or that otherwise violates the Safari Terms of Service is strictly prohibited. layers so that there’s no harsh transition where it stops using the top layer and reverts to the bottom. Applying these Blending Options produces Figure 7.15. As with Figure 7.12, it isn’t the best that can be done with this picture, but there’s a real shortage of alternatives if you’re trying to get the disastrously yellow original into acceptable shape in a minute or less. An even easier use of the Blend If sliders took place in Figure 7.8B, where I borrowed a red jacket from one image and put it in another. At that time I had two images: an LAB version that was good every- where except the jacket, and an RGB file in which the jacket was the only worthwhile thing. I converted the RGB document to LAB and pasted the other file as a layer on top of it. Then I changed Blending Options to exclude (that is, use the bottom layer for) anything that measures quite A –positive. That could also have been done in RGB ,but it would have taken two channels’ worth of sliders, not to mention an extra layer. If I had asked to exclude everything that was very dark in the green channel, the jacket would have been covered, but so would every neutral dark point in the image. So, the setting would have had to be modified to exclude anything that was very dark in the green and not dark in the red channel. It Only Takes a Minute Before wrapping up the first half of our jour- ney through LAB , two quick tech notes on the last image. First, in principle both the highlight and shadow adjustments could have been done on the same line in the Blending Options menu, but it was better to split them as shown, because of range issues. The top Summing Up: LAB and the Workflow 159 Figure 7.15 The final correction merges Figures 7.13A and 7.13B in the manner defined by the Blending Options. Figure 7.14 Layer Blending Options, available via the Layers palette (top left), restrict the appearance of the top layer based on the contents of either or both layers, using slider controls (bottom right). Chapter 7. Summing Up: LAB and the Workflow Page 25 Return to Table of Contents Chapter 7. Summing Up: LAB and the Workflow Photoshop Lab Color: The Canyon Conundrum: And Other Adventures in The Most Powerful Colorspace By DAN MARGULIS ISBN: 0321356780 Publisher: Peachpit Press Prepared for Kanchana Karannagoda, Safari ID: kanchana@ceybank.com Print Publication Date: 2005/08/08 User number: 910769 Copyright 2007, Safari Books Online, LLC. This PDF is exclusively for your use in accordance with the Safari Terms of Service. No part of it may be reproduced or transmitted in any form by any means without the prior written permission for reprints and excerpts from the publisher. Redistribution or other use that violates the fair use priviledge under U.S. copyright laws (see 17 USC107) or that otherwise violates the Safari Terms of Service is strictly prohibited. layer had already been lightened by the L curve of Figure 7.13. As the very darkest point stayed constant but medium grays got lighter, there was a longer distance between pure black and a gray than on the bottom layer. And, conversely, less distance between a white and a gray. Stated differently, the top layer devotes more space to shadows and the bottom layer more to highlights. It’s sometimes hard to get the slider settings to precisely what we want. It helps if the range of what we’re trying to home in on is relatively long, as moving the sliders a short distance will have less of an effect. Second, we can save even more time by storing some of these maneuvers as Photo- shop Actions, or doing other things to auto- mate the process, such as creating a Droplet, a location in which you can drop files for batch processing. You can, for example, do a batch conversion of a slew of files to LAB ,and even drop a layer on top of each with the Blending Options premade to exclude the highlights and shadows, just in case. Actions store a series of commands so that they can be executed with a single keystroke. For anyone whose workflow is somewhat repetitive, they’re very valuable, whether or not LAB is involved. The focus of these first seven chapters has been on global maneuvers that don’t require much expertise but make the picture look better, sometimes a whole lot better, than more conventional methods. At the same time, I’ve tried to point out the types of images in which LAB falls short, and also (as in this chapter) where it’s useful if you’re pressed for time. We now move on to more advanced applications. If you can make use of them, so much the better. But even if you only master what we’ve covered so far, the basic control of LAB curves, sharpening, and blurring, that’s going to be enough to make a sizable improvement in the quality of your images, particularly if you’re in a hurry. And if you’re not, the best is yet to come. 160 Chapter 7 The Bottom Line How LAB fits into the workflow depends on the type of images being used and especially on how much time is allotted to each. For those in a hurry, LAB offers the biggest bang for the buck. When there’s more time, each picture needs to be analyzed to see whether LAB is appropriate at all. The chapter introduces three techniques that work especially well in LAB : the Shadow/Highlight command, the use of luminosity masking, and the use of layer Blending Options. With these three tools, it’s possible to construct an all- LAB workflow, if that’s what’s desired. Chapter 7. Summing Up: LAB and the Workflow Page 26 Return to Table of Contents Chapter 7. Summing Up: LAB and the Workflow Photoshop Lab Color: The Canyon Conundrum: And Other Adventures in The Most Powerful Colorspace By DAN MARGULIS ISBN: 0321356780 Publisher: Peachpit Press Prepared for Kanchana Karannagoda, Safari ID: kanchana@ceybank.com Print Publication Date: 2005/08/08 User number: 910769 Copyright 2007, Safari Books Online, LLC. This PDF is exclusively for your use in accordance with the Safari Terms of Service. No part of it may be reproduced or transmitted in any form by any means without the prior written permission for reprints and excerpts from the publisher. Redistribution or other use that violates the fair use priviledge under U.S. copyright laws (see 17 USC107) or that otherwise violates the Safari Terms of Service is strictly prohibited. [...]... while we’re still in LAB is a good prediction of what we’ll have once we convert to RGB When going into CMYK, however, there’s a complication Photoshop looks at LAB equivalents, even when converting an RGB file Under ordinary circumstances, there’s little difference between a file that goes from LAB to CMYK and the same file converted from LAB to RGB first and then to CMYK If the LAB colors are even close... highly counterintuitive step of converting from LAB to RGB and only then to CMYK is indicated Remember, the LAB file is demanding a sky that’s not only lighter, but far, far bluer than in Figure 8.13 Faced with that impossible demand, it’s hard to predict how Photoshop will react A monitor, however, is an RGB device When it displays an LAB file, it uses internal Photoshop logic to translate it into the RGB... typing in a PMS number, it supplies Photoshop with LAB equivalents for each When you and I try to emulate these PMS colors in RGB or CMYK files on our own systems, we’ll get different numbers again unless our definitions are the same— but we’ll theoretically get the same colors, because we both converted from the same original LAB values (Note: this applies only to Photoshop 7 or later Earlier versions... and returned to the LAB document Wanting to replace the A and B channels with uniform values of 45A61B, I made a duplicate layer, then Select: Select All; Edit: Fill>Foreground Color Having thus created a layer that was only a flat color, I changed the layer mode from Normal to Color This blending mode is ordinarily most valuable when the file is not in LAB, because it emulates the LAB behavior of separating... Shall Have More Anon So, if you’re planning to make duotones, forget this cockamamie LAB method, with one exception Remember, Figure 8.4A is about as colorful a duotone as you can make using Photoshop s presets If you want something more violently colored, LAB is the way to get it You produce something like Figure 8.5A in LAB, convert it into CMYK or RGB, and apply curves that will create a true white... RGB file into LAB, being careful not to accept Photoshop s invitation to flatten it first, you might expect that there wouldn’t be any change, but there’s a big one The colored bar on the top layer reads 77L27A24B The blown-out area beneath it is largely 100L0A0B In RGB, that 100L was a killer It couldn’t change, and without such Chapter 8 The Imaginary Color, The Impossible Retouch Photoshop Lab Color:... The Impossible Retouch a change, Photoshop couldn’t allow any color at all In LAB, the file asks for a perfectly legal, if imaginary, color: 100L27A24B If we were just to return the layered file to RGB, we’d be back to Figure 8.8B, because Photoshop would lock in the 100L and then try to apply the 27A24B to it, without success But if we Layer: Flatten Image before leaving LAB (as I had to do here, to create... instructs Photoshop to use the top layer at f ul l strength in ver y light areas, such as the sky, and not at all in anything darker than the left half of the left-hand slider Anything between the two halves is to be a blend of both layers Figure 8.13 The final version of the image applies simple LAB curves to the original, Figure 8.12 Chapter 8 The Imaginary Color, The Impossible Retouch Photoshop Lab Color:... maximum in the four primary AB colors The top version was converted directly from LAB to CMYK; the bottom version went from LAB to RGB to CMYK Ordinarily, there wouldn’t be a difference between the two files, but when imaginary colors are in play, chaos reigns Chapter 8 The Imaginary Color, The Impossible Retouch Photoshop Lab Color: The Canyon Conundrum: And Other Adventures in The Most Prepared for Kanchana... the Impossible Retouch 169 As has been noted several times, the definitions of RGB and CMYK are not fixed; yours may vary from mine LAB has no such ambiguity: Photoshop offers only one flavor, although variants of LAB can be found in other applications If we each take the same LAB file, we each get the same colors and the same numbers If we each convert it to RGB, we still (in theory, at least) have the . play Summing Up: LAB and the Workflow 157 Chapter 7. Summing Up: LAB and the Workflow Page 23 Return to Table of Contents Chapter 7. Summing Up: LAB and the Workflow Photoshop Lab Color: The Canyon. construct an all- LAB workflow, if that’s what’s desired. Chapter 7. Summing Up: LAB and the Workflow Page 26 Return to Table of Contents Chapter 7. Summing Up: LAB and the Workflow Photoshop Lab Color:. picture (center). A B Chapter 7. Summing Up: LAB and the Workflow Page 20 Return to Table of Contents Chapter 7. Summing Up: LAB and the Workflow Photoshop Lab Color: The Canyon Conundrum: And Other

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