Section 6.1. The Basic Levels and Curves Routine

6.1. The Basic Levels and Curves Routine

The best place to start, once you've taken your image past the RAW stage (or if you shot JPEG or TIFF), is with a pair of adjustment layersone for making Levels adjustments and one for making Curves adjustments. Of course, you are wondering why on Earth you'd want to do that since you probably just made adjustments in Camera Raw. Well, one of the advantages of working with adjustment layers is that you can use the same adjustment several times on the same image. It may be possible that your image is so perfect right out of the camera or out of Camera Raw (or RAW Shooter, Capture One, Aperture, or Lightroom; see the Appendix) that there's no point in going any further. After all, one of the characteristics of a great artist is knowing when to stop. On the other hand, you don't want any more barriers than what your medium forces you to accept. I feel that I owe it to myself to try the tweaksunless time simply doesn't allow it.

NOTE

As I mentioned in Chapter 5, one of the things I've done to save you time is create an Action (actually it was Doug Sahlin's idea) that I call the magic Workflow Layers Action. You can download it from either the O'Reilly site (www.oreilly.com/catalog/digphotoet/) or from www.kenmilburn.com. Figure 6-1 shows the Layers palette (choose Window Figure 6-1. The Layers palette that the Workflow Layers Action produces. Assign this action to a key that doesn't conflict with anything you do often.

After opening your image from Bridge, use both the Levels and Curves commands to tweak the adjustments that either your camera or Camera Raw made to the original image. Levels are used to fine-tune the values in the three main areas of the image, much as if you made a simple S-curve in Curves. Then you can use Curves to tweak the contrast in two or three additional brightness ranges within that same image. Don't bother yet with masking these channels. Chapter 7 describes numerous techniques to create masks for layers and then use them to adjust very specific areas within the image. This is another step in the workflow called Targeted Adjustments.

NOTE

Make sure you exported your files from Camera Raw (or whatever application you use to process your RAW files) as 16 bits. In the last three or four chapters of the book, you may have to switch to 8 bit. However, in the meantime, you want to maintain as much data in the image as possible to keep posterization to a minimum for as long as possible.

6.1.1. Levels for Shadow, Highlight, and Overall Brightness

This is the Levels routine I use on all my images. When I finish, I know it is exactly as I want it. Then, if I want a certain effect, I can come back and modify this command as the interpretation I'm ultimately looking for begins to shape up.

1. Go to the Levels adjustment layer that was created by the Workflow Layers Action or any layer. Double-click its Layers icon.

2. Adjust each color channel individually. Don't make any adjustments in the RGB channel until the very end of this exercise. Press Cmd/Ctrl-1. The Red channel's Histogram appears. Look to see if the Histogram mountain "touches ground" at either end before it reaches the frame. If it does, move that end's slider (Highlight or Shadow) just barely to the left of the touchdown point. Do not touch the midpoint slider.

   NOTE

   Don't perform Steps 2 or 3 if you used a color or grayscale card to match color balance in Camera Raw (e.g., for predetermined colors for catalogs or logos or because you wanted white balance to be correct regardless of subjective considerations).

3. Repeat Step 2 two more times, once after pressing Cmd/Ctrl-2 for the Green channel and once after pressing Cmd/Ctrl-3 for the Blue channel. The colors in the image are now balanced. You'll probably be surprised at how much better it looks.

4. Adjust Brightness, Contrast, and Midtones by using the composite (aka RGB) channel's Histogram and sliders. Adjust the Highlight and Shadow sliders just as you did in the color channels. This is often not necessary because of the adjustments you just made, but if it is, follow Nike's advice and just do it.

5. Adjust the midtone slider to get the overall brightness you want. Don't even try to get the right look for a specific area of the image just because it's important. Not nowit's just not the right time. You want the overall balance to be right. Figure 6-2 shows the before and after of an image.

   Figure 6-2. Before (left) and after (right) levels adjustment.

6.1.2. Curves for Adjusting Contrast in Specific Brightness Areas

Now is the time to get the brightness and contrast correct for the most interesting or decorative portions of the image. Which area this is will depend entirely on the picture you've taken and your interpretation of it. You may want to darken some blocked highlights, or increase the contrast in the midtones to make the subject of interest "pop" or to simply block some shadow detail in a specific area so that it doesn't cause a distraction. This will probably be easier to visualize if we start with an example. Figure 6-3 shows an image after it was treated with the Levels adjustment layer but before using the Curves routine described next. The right is the result of the Curves Layer adjustments.

Figure 6-3. The image after adjustment with the Levels layer (left) and adjustment with the Curves layer (right).

Here's the step-by-step process for changing the Curves adjustment layer for several specific areas of brightness in a given image:

1. Double-click the Curves icon in the Curves adjustment layer bar in the Layers palette. The Curves adjustment dialog appears (see Figure 6-4).

   Figure 6-4. The Curves adjustment dialog as it appears when first opened.

2. Place your cursor over the area you want to change and press Cmd/Ctrl. (I find that it's generally the mid-highlights and shadows that need a bit of added contrast, as well as some lightening or darkening.) The cursor changes to a dropper. Click while the dropper is exactly over the color you want to change. A spot will appear on the Curve line at the exact point that corresponds to the brightness level you picked. Leave it alone until you've picked another couple of areas that need changing.

3. Look at what you have. You will want to raise the points that represent the areas to brighten and lower the ones to darken. Check the Preview Box so you can see what you're doing. I find it is easier to change the position of points with the arrow keys because the changes happen in small and exact increments.

As you raise or lower the points, notice that the contrast of areas between the two points increases as the Curve line becomes steeper. You may want to plot additional points to change the shape of the curve.

To isolate a point so that little changes on either side of its brightness, place two points on either side. This will keep the curve from moving. Figure 6-5 shows the Curves adjustment layer dialog as it looked after the adjustments from the right side of Figure 6-3.

Figure 6-5. The Curves dialog after making the necessary adjustments to get the results shown in Figure 6-3.

NOTE

With a little practice, you may know in advance what you want your curve to look like. When that day comes, you can save a lot of time by choosing the Pencil tool in the Curves dialog and simply drawing the curve freehand. It is usually a bit jerky, but you can click the Smooth button. The curve is still modified by clicking points and dragging them.