Beyond Adjustment LayersApplying Levels, Curves, Hue/Saturation, and the other adjustments as adjustment layers offers tremendous flexibility and power, but it isn't always the quickest or easiest way to fix your images. Also, while these tools are powerful (and essential to learn), they don't really relate to anything we did in the wet darkroomthey're much more akin to the controls on prepress scanners than to anything photographic.The layer blending modes open up an entirely different way to edit images. Bruce likens use of the blending modes to making the images edit themselveshe actually spent the best part of a year eschewing the use of Curves layers as anything except a means of applying blending modes, just to see how far he could take this approach.He concluded that Curves is indeed an indispensable tool, but nowadays he's more likely to use it as a fine-tuning tool, doing the heavy lifting with blending modes. Using Layer Blending ModesWhen we started our blending mode experiments, we duplicated the Background layer, and applied the blending mode to the duplicate layer. We quickly found that we could obtain the same result by applying an adjustment layerany kind of adjustment layerwithout making any adjustments, and setting the blending mode of the adjustment layer rather than duplicating a pixel layer.We quickly settled on using Curves layers to do thisLevels layers take longer to create because Photoshop has to build the histogram that appears in the Levels dialog box, and if we need to make actual adjustments, more often than not we need to do so with Curves. Applying blending modes with Curves layers offers three advantages over doing so with pixel layers.The files are smaller than ones made with pixel layers when we save as Zip-compressed TIFF. (Uncompressed, they may be a little larger because the adjustment layer always has a layer mask. But if you apply a layer mask to the pixel layer, this difference goes away). In Photoshop CS, adjustment layers in 16-bit files didn't compress wellwe're happy to report that CS2 does a much better job in this regard.Adjustment layers automatically come with a layer mask. Since much of the appeal of working with blending modes comes from painting adjustments in and out by painting on the layer mask, having one created automatically saves us time.If we need to make actual adjustments beyond just applying the blending modes, we have Curves ready and waiting for our edits. Before looking at actual examples, though, it's time to get your head around just what the blending modes do. They're sometimes referred to as "procedural blends" because they all use some arithmetical formula to calculate pixel values based on the values in the overlying and underlying layer. (Of course, when we use adjustment layers without making actual adjustments, the overlying and underlying pixel values are the same, which actually makes things a little simpler to understand.) Layer Blending ModesThe previous examples were relatively simple, using straightforward adjustment layers for global editing, with some painting on the layer mask for local corrections. However, when you combine adjustment layers with the power of blending modes, you open up a whole new world of possibilities.One advantage of using blending modes rather than simply stretching and squeezing the bits with Levels and Curves is that blending interpolates tonal values, producing smoother results. We'll show you some examples of how we use some of the blendng modes, but we encourage you to experimentthere are plenty of new techniques waiting to be discovered.The blending modes are arranged in logical groups, according to the way they function.The Independent modes. Normal and Dissolve both replace the underlying pixels with the overlying pixels (in the Normal or Dissolve layer) when the layer is at 100-percent opacity. At lower opacities, Normal blends the overlying pixels with the underlying ones according to opacity, while Dissolve replaces pixels randomly (see Figure 7-12). Figure 7-12. Normal and DissolveFigure 7-13. The Darken modesFigure 7-14. The Lighten modesFigure 7-15. The Contrast modesFigure 7-16. The Comparative modesFigure 7-17. The HSL modesLayer Blending in PracticeIf the preceding discussion has rendered you crosseyed, some less-abstract examples may be helpful. The blending modes we tend to use most are Multiply to build density, Screen to reduce it, Soft Light and Hard Light Chapter 9, Sharpeness, Detail, and Noise Reduction).Tip: Stop-Based Corrections with Multiply and ScreenIf you're more comfortable thinking in terms of f-stops than in levels or percentages, thank our friend and colleague Jeff Schewe for this insight. You can lighten and darken shadows by 1 stop by applying Screen and Multiply, respectively, at an opacity of 38 percent.For a half-stop adjustment, use 19 percent. For a one-third stop, 13 percent seems to be slightly closer than 12, and for a quarter stop, 9 percent is the magic number. Multiply and Screen always affect the shadows more than the midtones and highlights, so the analogy with f-stops isn't perfect, but it's still a useful rule of thumb.The practical examples that follow don't pretend to exhaust the power of blending modes. They're simply illustrative examples that we hope will fire your imagination and pique your curiosity. Rememberone of the huge benefits of working with layers is that you can't do any harm until you flatten the image, so feel free to experiment. Photoshop offers many ways to produce similar if not identical results, and we each find methods that work for us. Building density with MultiplyThe best analogy we've found for Multiply mode is that it's like sandwiching two negatives in an enlarger. Mathematically, Multiply takes two values, multiplies them by each other, and divides by 255. Practically speaking, this means the result is always darker than either of the sources.If a pixel is black in the base image, the result after applying an adjustment layer with Multiply is also black. If a pixel is white in the base image, the adjustment layer has no effect (white is the neutral color for Multiply). We use Multiply with Curves adjustment layers to build density, particularly in the highlights and midtones of washed-out images like the one in Figure 7-18. Figure 7-18. Building density with Multiply[View full size image] Adding Contrast with Hard LightWe use Soft Light, Hard Light, and Overlay to build contrast (since the overlying and underlying pixels are identical, Hard Light and Overlay produce exactly the same result). We use Soft Light for smaller contrast boosts, and Hard Light or Overlay for stronger ones. All three blend modes preserve white, black, and midlevel gray, while lightening pixels lighter than midlevel gray and darkening those that are darker. Figure 7-19 shows a contrast adjustment with hard light. Figure 7-19. Increasing contrast with Hard Light[View full size image] Adjusting color balance with ColorWhile we sometimes use Photo Filter adjustment layers for warming and cooling effects, we find that Solid Color layers set to Color blending with a low opacity offer more controlwe can tweak the color by double-clicking on the layer without having to tunnel through the Photo Filter dialog box.We start out by creating a Solid Color layer of approximately the color we want, then we reduce the opacity, typically to around 1020 percent. Then we fine-tune the color to get the result we wantwe usually tweak the Hue and Saturation fields of the Color Picker by placing the cursor in them and pressing the up and down arrows on the keyboard.Figure 7-20 shows the process and the result of adding a Solid Color layer. We started out by picking the approximate colorthe image is a little green, so we picked its opposite, magentathen we used the color picker to fine-tune the solid color to get the result we wanted. Now the edited image does a much better job of conveying the oppressive heat, the omnipresent smoke and dust, and the languor of the millennia-old ritual that takes place at dawn on the Ganges. Figure 7-20. Adjusting color balance with Color[View full size image] Opening shadows with ScreenScreen is literally the inverse of Multiply. The best real-world analogy we've heard comes from Adobe's Russell Brown. Screen is like projecting two slides on the same screen. The result is always lighter than either of the two sources.If a pixel is white in the base image, the result is white, and if it's black in the base image, the result is also black (black is the neutral color for Screen). Intermediate tones get lighter. We often use Screen to open up dark shadows.If you're a techno-dweeb like we are, you probably want to know what Screen does behind the scenes. Photoshop inverts the two numbers (subtracts them from 255) before doing a Multiply calculation (multiplies them by each other and divides by 255); then the program subtracts the result from 255. That's it. Now, don't you feel better knowing that?Bruce shot the image in Figure 7-21 from his deck, using a Canon EOS 1Ds, on a typically foggy San Francisco late afternoon. The image holds detail in both highlight and shadow, but the foreground is dark and muddy, an ideal candidate for opening up with Screen blending. We want to preserve the dark sky and hold the detail on the sunlit buildings across the bay, so we'll make the adjustment, then localize it using the layer mask. Figure 7-21. Opening shadows with Screen[View full size image] Creating the maskWe could get a pretty good result by painting with a large soft-edged brush, but we found we could do even better by first making a marquee selection that covered the dark sky, filling the selection with black on the layer mask, and then making a second marquee selection on the bright area, and refining it with Color Range, as shown in Figure 7-22. Figure 7-22. Building the layer mask[View full size image] Complex Layer BlendingThe preceding examples were relatively simple. While we always look for simple fixes, some images entail more complexity than others. The image in Figure 7-23 is a hardy perennial that we nevertheless continue to improve as both the tools and our understanding of them evolves. Figure 7-23. An image with many problemsFigure 7-24. Addressing the color cast[View full size image] Figure 7-25. Fixing the lens flare[View full size image] Figure 7-26. Adding contrast with Hard Light[View full size image] Figure 7-27. Building density with Multiply[View full size image] Figure 7-28. Brightening the image with Levels[View full size image] Figure 7-29. Adding local contrast by painting in a Soft Light layer[View full size image] Figure 7-30. A cooling adjustment with Photo Filter[View full size image] Figure 7-31. Adding global contrast with a Soft Light layer[View full size image] Figure 7-32. Hue/Saturation adjustments[View full size image] Figure 7-33. A Color Fill layer[View full size image] Naming the layersThis image contains only 10 layers, not a huge number by any stretch of the imagination, but it isn't at all obvious what each layer does. We can glean a few clues by looking at the layer masks, but if we return to this image a year or two from now, we'll pretty much have to resort to turning the layers on and off to figure out what each one does.It's a good idea to get into the habit of naming your layers informativelyjust double-click on the layer name in the Layers palette, and type in a more informative name than "Curves 78" or "Color Fill 15." Figure 7-34 shows how we'd like the Layers palette to appear when we revisit the image. Figure 7-34. Naming the layers[View full size image] Letting the Image Edit ItselfWe confess to being lazy. One of the ways that laziness manifests itself is that we're always looking for simpler solutions, which in the field of digital imaging can be difficult and occasionally dangerous. But using the contrast, darken, and lighten blend modes to adjust tonality is one of those few solutions that is both simple and safe.Bruce calls this "letting the image edit itself" because rather than having to place curve points and carefully manipulate them, the image content does all the work. If you need more contrast, apply a Soft Light or Hard Light layer. The blending mode takes the contrast that's already in the image and increases it, with no danger of clipping, and no futzing around in the Curves dialog box. Likewise, when you need to lighten or darken an image, Screen and Multiply do those things proportionally, again with no danger of clipping. Moreover, the blend modes tend to introduce less hue-shifting than major tonal moves with Curves.Each layer affects all the layers underneath it, so we often end up going back to a previous layer to tweak it to take account of the effect of the ones above it. Using the blend modes, we can simply adjust the layer opacity without having to open dialog boxes, or when we need to make localized changes, we edit the layer masks.Once you get accustomed to working with the blend modes, you'll find that they're useful for many different kinds of edits. But it's important to remember that the conventional tools still work too! Mixing and matchingThe following example shows how we mix blending modes with "normal" techniques. A reasonable rule of thumb is that if a blend mode edit doesn't get you where you want to be fairly quickly, and it's not a masking issuean edit that needs to be localized to a specific area in the imageit's probably time to go back to the "normal" Photoshop tools.The image shown in Figure 7-35 is an unadjusted scan from a Kodak Portra 160 NC color negative. Two quick blend mode edits put it into a much better state for the subsequent fine-tuning. Figure 7-35. Heavy tonal lifting with blend modes[View full size image] Figure 7-36. Fixing color balance with a Color Fill layer[View full size image] Figure 7-37. A local correction with a Color Fill layer[View full size image] Figure 7-38. A local correction with a Hue/Saturation layer[View full size image] Figure 7-39. Warming the clouds with a Color Fill layer[View full size image] Figure 7-40. Tonal fine-tuning with blend modes[View full size image] Figure 7-41. Warming with a Color Fill layer[View full size image] Figure 7-42. A masked Curves correction[View full size image] |