Chapter 11. Special Purpose Processing This chapter is about three highly useful techniques: image stitching, extended dynamic range images, and photopainting. All of these techniques can extend your marketing and creative capabilities significantly. They have also helped quite a few photographers establish a unique look and style. Best of all, none of these techniques absolutely require any special equipmentunless you consider a tripod to be special. Use Duplicates for Complex Projects All of the processes in this chapter should be performed on a duplicate of one or more images that you've brought to this stage. Two of the three processes discussed here actually require multiple images (or multiple interpretations of the same image). For that reason, you may want to go back and re-interpret the contributing images so that they'll match or blend to maximize the desired effect for one of these processes. You'll learn how to easily do that without compromising what you've already done to the contributing images. Having said all that, there are some exceptions to the duplicate image requirement. Panoramas and Photoshop HDR images that are taken directly from RAW files don't really need that backup, since the RAW files themselves are indestructible. 11.1. Stitching Images for a New Point of View One of the best ways to catch a viewer's attention is with a panoramic view of a subject, whether it is a close up of a beached whale body or a view of the Grand Canyon. One of the reasons for this is that panoramas have become much easier to create since digital photography has come along because there's no requirement for an expensive specialized camera. Also, you don't need to use an expensive, super wide angle lens on a large format camera to get a large, high-resolution image. Without changing its look much at all, Photoshop's built-in panoramic stitching software has become much more versatile and much more accurate with each new version of Photoshop. My one argument with it is that it doesn't always blend the images together as invisibly as I'd like, but I'll show you a way you can usually work around that, too. 11.1.1. Taking the Best Shots for Panoramas Once again, these images will turn out best if you plan ahead and capture the best content before you even get to Photoshop. Before I get into the details of how to make the Photomerge subprogram work, you need to know that there are some special techniques required for shooting a panorama if you expect the end result to look anything but amateurish: Get a tripod or pan-head that will let you rotate your camera on the absolutely level If your tripod twists, rocks, or slants as you pan from one side to the other, the image will have to be cropped quite a bit. Furthermore, you may have to take the extra trouble to align the images manually after placing them on separate layers. You can get away with cheap and flimsy tripods when shooting single frames by just making sure the camera doesn't shake when the shutter is depressed or while the shutter is open. When you shoot panoramas, you want to make sure the camera doesn't rock and roll between exposures. Rotate the camera on its optical axis Special pan heads made for shooting panoramas make it possible to mount the center of the optical axis directly over the pivot point of the tripod thread. Panoramic heads that allow you to mount the camera vertically are best, since there are more photos for a given area of arc. This makes for cleaner stitching and higher resolution. The optical axis is not the tripod thread. It is the exact point at which the image becomes inverted from left-to-right and top-to-bottom as it passes through the lens. Rotating on this axis is especially critical if there are objects, such as railings or plants, in the foreground of the image. Put a level in your camera's hot shoe Then you can make sure the panorama is not tilting as you rotate. Just rotate the camera as far as needed for the panorama you want and make sure the level bubble doesn't change position. Use a wide angle lens This isn't a strict rule, but your panorama will require fewer stitches and will show more of the scene from top to bottom. On the other hand, the lens shouldn't be so wide angle that it has lots of barrel distortion. Someplace between 21mm and 35mm in focal length generally works well. Be very careful not to zoom in between shots Zooming means that Photoshop also has to try to figure out how to rescale the image and you may have to do it manually or you may have to crop the final image more than you'd like. Overlap each shot by about 30 percent on each side If you're lucky enough to have a "rule of thirds" grid that fits over your preview monitor, it's much easier to judge overlapping. Also, many panorama pan heads have adjustable click stops that alert you when you've rotated exactly the right amount. If you're thinking that a panoramic head is worth the investment, you're rightyou'll have much better luck in creating successful stitched panoramas. Keep your exposure consistent from frame to frame Do not use any of your camera's automatic modes. If you do, the exposure will change from one frame to the next. This makes it much harder to blend the frames smoothly from one frame to the next. Instead, put your camera in spot or center metering mode, aim the camera at the most important part of the panorama, and take a reading. Then switch to M(anual) mode and compensate the exposure reading you got from the auto reading so that the f- stop is around f-11 for the best compromise between depth of field and sharpness. NOTE More expensive lenses can be stopped down as low as f-16 without loosing significant sharpness. Also, thanks to their exaggerated depth of field, pocket cameras can be excellent for panoramas, but only if they provide access to manual exposure. 11.1.1.1. Rotating at the optical axis If the panorama you're shooting requires that you stay right on the optical axis as you rotate, get a panoramic pan head that works with any camera. I can use my panorama head either on my pocket camera or DSLR. Set up the camera and the pan head in front of two vertical objects that are a few feet apart. I usually do this in the studio with two light stands. I place the stands so they're centered in the frame. Then I mount the camera on the panorama head (not the tripod's pan head, but the accessory shown in Figure 11-1). Typically, the optical axis is going to be about one-third the distance between the tripod thread and the outermost end of the lens. Then I put the camera and the panorama head on the tripod and aim and level the camera so that the closest light stand (or other vertical object) completely blocks my view of the other. Then I rotate the camera. If, as I rotate, I begin to see the second lamp stand, I'm off-axis. Figure 11-1. Diagram of optical axis test setup. Keep testing by moving the camera back and forth on the panorama head until no amount of rotation reveals the second object. After a few times doing this, you'll become instinctively good at it. If you always use the same fixed focal length lens for your panoramas, you'll only have to do this once per camera, provided you mark and label its place on the panorama head. If you use a zoom lens at varying focal- lengths, you'll have to do it every time you set up a shot or make sure nothing in the scene is ever any closer than 10 to 20 feet away. One more thing: you want to orient the camera vertically in respect to the direction of the panorama whenever possible. This means higher resolution from the top to the bottom of a strip, less rotational distortion from frame to frame, and smoother blending from frame to frame. The diagram in Figure 11-2 illustrates this. Figure 11-2. If you have a panoramic pan head that allows the camera to be mounted vertically over the optical axis, you will get smoother and more precise stitching in vertical panoramas. 11.1.2. One Dimensional Versus Two Dimensional Panoramas The panoramas that most of us are used to looking a t consist of only one horizontal row of images. However, Photomerge will now let you stitch vertically as well a horizontally. So you can have a panorama that consists of multiple rows. You will need to drag most, if not all, of the images into place. Figure 11-3 shows you the images used to make a 1D panorama and the completed panorama after it has been stitched in Photomerge. A 2D image would have one or more rows of images above and below that center row. Figure 11-3. The component images and complete panorama. Here's how to stitch a 1D panorama in Photomerge (start with Step 1 if you shot your panoramic in RAW format; if you didn't, go to Step 4): 1. In Bridge, select all the images for the panorama and press Enter/Return. They will all open in Camera Raw. Select the thumbnail for the image in the middle. Keep it selected. 2. Click the Select All and Synchronize buttons. When the Synchronize dialog appears, look to make sure that all the boxes are checked and press Return. 3. Choose the image that's closest to center and make your RAW adjustments. You have just ensured that all frames will be processed the same way, so click the Open button. All the images will open in Photoshop. 4. Choose File Automation Photomerge. A small Photomerge dialog appears with the names of all the files that are currently open in Photoshop. If you see any that you don't want to include in the panorama, select them and then click the Remove button. If you handheld the panorama shots, uncheck the Attempt to Automatically Arrange Source images button. Otherwise, leave it checked and press Enter/Return or click OK. 5. The Photomerge application dialog will appear, looking something like what you see in Figure 11-4. If you left the Attempt to Automatically Arrange Source images button off in the p revious step, the photos will all be arranged in the window at the top. If you checked the Automatically arrange box, they'll look like the best Photomerge can do at automatically arranging them. Actually, there's no harm in letting Photomerge do it automatically all the time. If you don't luck out, you can always drag the images into the frames bar at the top and then place them yourself. You can even press Cmd/Ctrl-T to correct perspective on an image if you can't quite get the edges of objects to match. You can also click the Rotate tool if you tilted the camera too much as you were panning. Figure 11-4. The Photomerge dialog. 6. You can try the Advanced Blending if you like. Frankly, most of the time I find it makes a big mess. Thankfully, you have to click Preview to see what it does and if you don't like the result, you can click an Exit Preview button. NOTE If you're having trouble with getting interframe blending to look smooth, check the Keep as Layer box. I can often make very smooth blends after the image opens in Photoshop with each image on a separate layer. I just choose the Move tool and Cmd/Ctrl-Opt/Alt-click the portion of the image that's on the layer I want to fix. Then I choose the Eraser tool and a very large and soft brush to do my blending. If that doesn't do the whole job, I'll blend seams or get rid of shadows with the Clone tool after flattening all the layers. Here's how to stitch a 2D panorama in Photomerge: 1. Shoot the frames as suggested above. If shooting in vertical orientation doesn' t show enough of the scene from top to bottom, you may have to add a row or two above. Use playback mode on your camera and move back to the first shot in the series. Line up your view find frame with that frame and then tilt the tripod up just enough so that the top and bottom frame overlap by about 30 percent. Be sure to lock down the height of the camera's tilt and then shoot another row of images just as you shot the first. 2. When you load the frames, you probably won't want to have the program stitch the m automatically. Instead, put the middle row together first, then the one above it, then (if there is one) the one below it. 3. Again, if you're having trouble with blends, check the Keep as Layers box and try a bit of hand retouching and layer blending. 11.1.3. Vertical Versus Horizontal Panoramas We usually think of panoramas in the horizontal, but imagine needing to shoot a tall building from just across the street. You simply don't have room to back up far enough to get the whole building into the picture. Besides, even if you could, you might not have enough resolution in a single frame to make the six-foot tall poster you'd like to make of that building. It's time to shoot a vertical panorama. It's tougher to find a panorama pan head that rotates vertically on the optical axis, although some can be used that way, especially since you want to shoot the vertical with the camera in a horizontal (landscape) position. The good news is that most verticals don't require more than a few frames. If you pan vertically more than about 45 degrees, chances are the end frames won't show anything more than blank sky or pavement. Staying on optical axis is tougher, but the chances are better you won't have foreground objects to worry about. Also, as long as you know what the limitations are, the better your chances for success at working around them. I've often found myself in situations where I needed to show something like an office building or a waterfall and simply didn't have time to set up a tripod. So I've just been very careful to stand absolutely rigid and to shoot the middle image first. I then tilt up twice by about 20 degrees and take a shot with each tilt, then go back to the center and tilt down twice. Because I know there's a good chance of error and I'm shooting digitally and not "wasting" film, I shoot this same sequence at least twicemaybe four times. Then I have a much better chance of finding the three to five images it will take to make my "vertirama." The stitching procedure is the same. However, if automatic stitching doesn't work, try placing the images yourself. Also check the Save as Layers box. The image in Figure 11-5 required that I do both to keep from getting "double exposures" in the tree trunk on the left and for the head of the guitarist. The problem was easily resolved by saving as layers and then doing my own blending with the Eraser tool. Figure 11-5. You could get this same shot with a very wide angle lens, but you'd probably also get more barrel distortion and about 70 percent less resolution. 11.1.4. Matrix Stitching for Super High Resolution Did you know that as long as your subject doesn't move, you camera has unlimited resolution? Just do what you've been doing previously in this chapter, and then stitch the pieces together. There's one instance where the method of shooting described won't work, however: when you're shooting 2D artwork for very large and very high-resolution printing or for use on something like a billboard. The trick here is that you have to keep the camera parallel to the artwork for each of the shots in the stitch. In other words, you are shooting pictures in rows and columns and with the camera at the same distance from the subject in each of the cells of that matrix. To do this: 1. Mount the artwork on a flat wall and light it by placing two very soft (to minimize spectral reflections) light sources (umbrellas or lightboxes are my favorites) equidistant from the center of the image. 2. Use a polarizing filter to minimize the chance of any lighting "hotspots" on the 2D artwork. In any case, don't shoot that artwork from behind glass unless you have no other choice. 3. Place a strip of tape across the floor at exactly the distance from which you'll be shooting the art and make sure that the strip is absolutely parallel to the surface of the artwork. 4. Set up to shoot the center row of the artwork. Take each shot after moving the tripod or (better) camera stand. 5. Go back to your original start position, raise the camera (preferably with the tripod's center post) so that it frames the top portion of the image, and then repeat the procedure for the top row. When you've finished that, go back to the start position, lower the camera for the bottom row, and repeat the side- to-side shots. 6. Open all the shots in Photoshop and choose File Automate Photomerge. The Photomerge dialog opens. Make sure Open Files is the menu item already chosen from the Use menu. If that's not it, change it. Click OK. 7. The Photomerge dialog will open and, believe it or not, the program will automatically merge all three rows perfectly, as long as you've followed the instructions for shooting (Figure 11-6). Figure 11-6. This is how Photomerge arranged all the images automatically. 8. You may notice a couple of white streaks (Figure 11-7). Those could be retouched, but one hates to fool with another's masterpiece if you're being hired by a museum, gallery, or artist. However, when I checked the Save as Layers box, those lines disappeared and all I had to do was flatten the image. Figure 11-7. The final Photomerge image. Making a Montage with Photomerge You can make a montage with Photomerge and save quite a bit of time. Just open all the images you want in the montage, according to the previous processes in this chapter. Be sure to uncheck Snap to Image. Then position and rotate the images as you like and then do one of two things: check the Advance Blending box or the Keep as Layers box. If it's the former, you'll get a strange blending of all the images. If you keep as layers, you'll be able to resize and transform the individual layers, give them layer styles, do you own feathering, and use any of the layer Blend or Style modes. . Instead, put your camera in spot or center metering mode, aim the camera at the most important part of the panorama, and take a reading. Then switch to M(anual) mode and compensate the exposure. DSLR. Set up the camera and the pan head in front of two vertical objects that are a few feet apart. I usually do this in the studio with two light stands. I place the stands so they're