You can either crop and straighten pictures manually (you’ll learn how in a sec), or you can have Photos do it for you. If the latter method is the way you want to roll, then in Edit mode, click the Crop tool to activate it, and then click Auto. When you do, Photos analyzes the image, rotates it just enough to straighten any lines it finds, and smartly crops the image according to the Rule of Thirds (which is explained in the following list). If you don’t like the results, you can manually fine-tune the crop box to your liking using the techniques described below.

To take cropping and straightening into your own hands, follow these steps:

Don’t be alarmed that Photos tosses all those edge pixels—you can always get them back. If you crop an image and then immediately realize you’ve messed up and you’re still in Edit mode, click “Revert to Original,” choose Edit→Undo, or press ⌘-Z to go back one editing step. In Photos for iOS, tap Cancel, and then click Discard Changes. If you regret the crop next week, simply select the photo in Photos for Mac and choose Image→“Revert to Original.” On your iOS device, open the image in Edit mode and tap the red Revert button. After asking if you’re sure, Photos reinstates the original photo, discarding every change you’ve ever made to it.

To summon Photos advanced editing controls, open the Adjustments panel by pressing the A key on your keyboard or, in Edit mode, clicking the Adjust icon. When you do, you see three basic adjustment categories: Light, Color, and Black & White (see Figure 5-8). The first two categories contain a vertical slider (it looks like a white line) atop a row of thumbnails of the photo you’re editing. These are called smart sliders, and the thumbnails give you a preview of what that particular adjustment will look like applied to your picture. (The Black & White slider doesn’t show up until you click the row of thumbnails, at which point your image goes from color to black and white.) For example, to darken a photo, simply drag the Light slider toward the darker thumbnails on the left. To lighten it, drag the slider toward the lighter thumbnails on the right. What could be simpler?

Figure 5-8. Photos’ Adjustments panel gives you maximum control over color and lighting. This figure shows a simulated split-screen view of a picture corrected using the Light and Color smart sliders (circled). The right half of the cat photo has brighter, more vibrant colors than the left half. Don’t let the simplicity of these sliders fool you; they’re more powerful than the ones in iPhoto and easier to use than the ones in Aperture and Adobe Photoshop Lightroom.

Smart sliders are smart because dragging one adjusts a slew of settings simultaneously. For example, dragging the Light slider adjusts a whopping six settings, including exposure, highlights, shadows, brightness, contrast, and the photo’s black point (which controls how light or dark the color black appears in your image). To expand a smart slider to see—and use—its sub-sliders, point your cursor at the smart slider’s name, and then click the icon circled in Figure 5-9, right. This brilliant two-tier setup lets those who are aren’t comfortable with advanced adjustments fix their images using smart sliders while letting more experienced folks take fine adjustments into their own hands with the sub-sliders. But even if you’re nervous about playing with advanced settings, there’s no reason not to experiment with the sub-sliders, because you can always undo what you’ve done.

Figure 5-9. Here’s an unexpanded (left) and expanded (right) view of the Light smart slider. Once it’s expanded, you can drag its sub-sliders to fine-tune corrections or double-click a sub-slider’s number and enter a new value. To put the picture-fixing responsibility in Photos’ hands, click the Auto button that appears when you point your cursor at a smart slider’s name, like the one the cursor is pointing at in the upper right here. Consider the Auto button a great starting point: Click it, and then fine-tune the smart slider.

And that’s not all—there’s still more power lurking in the Adjustments panel. To keep the panel uncluttered, Photos initially shows you only three basic correction categories: Light, Color, and Black & White. However, there are several other adjustments worth trying. To see them, click the Add button at the panel’s upper right. When you do, the menu shown in Figure 5-10 appears. This menu contains adjustments that affect your image’s details—sharpen (Sharpen), definition (Definition), noise reduction (Definition), and vignette (Vignette)—as well as advanced adjustments of white balance (White Balance) and Levels (Levels).

Figure 5-10. Click the Add button to reveal this menu. Adjustments that are currently displayed in the Adjustments panel have checkmarks next to their names. To open another adjustment, click its name in this menu (Histogram [page 127] was added here). To save your current configuration of adjustments so they’re always open in the Adjustments panel, choose Save As Default at the bottom of the menu.

Undoing changes you’ve made in the Adjustments panel is easy. To undo everything you’ve done in the Adjustments panel, click Reset Adjustments at the bottom of the panel. To undo an adjustment in a specific category, click the tiny down-pointing chevron icon next to the category’s name and choose Reset. To remove an adjustment from the panel (so you don’t see it), click the same icon, and then choose Remove Adjustment. (You can always summon that adjustment again using the Add menu, as describe in Figure 5-10.)

To open the Adjustments panel in Photos for iOS, select a photo, tap Edit, and then tap the icon that looks like a little dial. The panel works pretty much the same as it does on your Mac except that it lacks an Add menu, so you can’t display the advanced adjustments that you get in Photos for Mac. Nevertheless, you get smart sliders for the same basic categories—Light, Color, and Black & White—plus you can easily access their sub-sliders. Figure 5-11 has more.

Figure 5-11. Left: Here’s the Adjustments panel in Photos for iOS, shown in vertical orientation. To access the smart sliders, tap an adjustment category’s name. To go straight to its sub-sliders, tap the down-pointing chevron icon to its right. Right: Once you’ve summoned and tweaked a smart slider (like the B&W slider shown here), a tiny gray dot (circled) appears above the smart slider, indicating its original position. To reveal and adjust its sub-sliders, tap the icon labeled here.

Using the Adjustments panel in Photos for iOS requires a lot of tapping to reveal the hidden controls because the device’s screens are so small, as Figure 5-12 shows. (Things look slightly different on an iPad because the screen is slightly bigger, so the controls aren’t quite so hidden.) When you tap and hold a smart slider or sub-slider, you’re not so much dragging the slider as you are dragging the controls underneath it—the thumbnails of a smart slider or the tick marks of a sub-slider. For that reason, you drag in the opposite direction that you want the slider to go. For example, to move a slider to the right, you tap and drag left; to move a slider to the left, you tap and drag right. It takes a little getting used to but it works really well, and the ability to edit your images in such powerful ways on an iOS device, using a free program, is awesome.

Undoing the changes you make in the Adjustments panel in Photos for iOS depends on what you’ve done. You can undo changes you’ve made with the Light and Color smart slider and sub-slider by tapping Cancel, and then tapping Discard Changes in the confirmation sheet that appears. This strips away all the edits you made to that image during this round of editing, and spits you out of Edit mode. Alternatively, you can undo specific changes by moving each slider that you changed back to its original position, which is indicated by the gray dot circled in Figure 5-11.

Figure 5-12. Left: When you tap to reveal any adjustment’s sub-sliders, you see this screen. Tap the chevron icon to the right of an adjustment’s name to show or hide that adjustment’s sub-sliders. To use a sub-slider, tap its name. Right: Here the Tone sub-slider in the B&W category is open, and what a difference it makes on this black-and-white photo! To turn off the black and white effect, tap the B&W button (circled). When you’re finished using the sub-slider, tap the button labeled here to return to the screen shown at left.

Photos for iOS’s Black & White category, on the other hand, works like an off/on switch, so you can turn off just the black-and-white bit without undoing any changes you made using the Light and Color categories in this editing session. For example, once you tap the B&W icon in Photos for iOS to reveal its smart slider and then you move the red smart slider, your image changes from color to black and white, and the little B&W label itself goes from black to gray (it’s turned on and circled in Figure 5-12). So, to restore your image’s color, you can turn off the black-and-white effect by tapping the label itself (it goes from gray to black).

When you’re finished using the Adjustments panel in Photos for iOS, you can do one of the following:

Over the next few pages, you’ll learn what all the settings in the Adjustments panel mean, and how to use them to improve your pictures. The remainder of this section focuses on Photos for Mac because the controls in Photos for iOS’s Adjustments panel work the same way.

You can indeed improve your pictures by dragging the Adjustments panel’s smart and sub-sliders around, but if you want to understand the changes you’re making and learn to use the sliders more effectively, you need to get cozy with your picture’s histogram: the colorful graph shown in Figure 5-10. Go ahead and add it to your Adjustments panel by clicking Add, and then choosing Histogram from the menu that appears.

A histogram is a self-updating collection of graphs that represent the dark and light tones in your picture. Chances are you’ve encountered a histogram before, say, on the screen of your digital camera. A histogram may look complicated at first, but it’s a terrific tool once you get the hang of using it. The data a histogram displays can tell you if the photo was properly exposed and what the lighting conditions were (harsh or dull, for instance). The histogram gets even more powerful when combined with a Levels adjustment, which you’ll learn about later in this chapter (Levels).

The first step in learning to read a histogram is to understand that digital images are made up of individual pixels (short for picture element) made from a combination of the primary colors: red, green and blue (let’s call these color channels). Within each pixel, each of these three colors has a brightness value that’s represented by the width of the histogram: no brightness is on the far left (0%) and full brightness is on the far right (100%). For Photos to display a histogram of your picture, it counts how many pixels there are at each level of brightness in each color channel. The result is three tiny bar graphs superimposed atop each other in the histogram: one for the red channel, one for green, and another for blue. (You can see an example back in Figure 5-10.) The taller the graph at any given point, the more pixels you have at that particular level of brightness in that particular color channel. If the graph reaches all the way to the top of the histogram, it means that particular color has been clipped—pushed to the highest possible brightness value, meaning you can’t see any details in the area that’s that color.

Within each graph, the scheme is the same: Your picture’s darker tones (shadows) appear toward the left side of the histogram, the lighter tones (highlights) appear on the right, and the tones in between (midtones) appear in the middle. So if you’re working on a very dark picture—a black cat at night, say—you’ll see lots of data at the left side of the histogram, trailing off to nothing toward the right. A shot of a white cat in the snow, on the other hand, will have lots of data on the right side of the histogram and very little on the left. The histogram in Figure 5-13, left, has a bunch of data bunched up on the left, so you can tell that the photo is too dark.

The width of these graphs reveal the picture’s tonal range—the total number of tones possible in the image, from dark to light—which you can compare to the total possible tonal range, which is represented by the width of the histogram. For example, a histogram with data that spans the histogram’s full width indicates the photo has a good balance of dark and light tones. In the histogram for a bad photo—a severely under- or overexposed one—the graphs are all bunched at one side or the other and may have some clipping. Rescuing those kinds of pictures involves spreading the data out across the histogram, as Figure 5-13 shows, and reducing the brightness of any clipped tones so you can see the details in those areas of your photos.

You perform these rescue missions using the Light and Color adjustments (described in the following sections) or a Levels adjustment (Levels). Which method is best? It depends on the picture, how much control you want, and how much time you have. Perfectionists who love to tinker will adore the precise control that only a Levels adjustment can provide (the one in Photos is as powerful as the one in Aperture), and everyone else will be happy using Light and Color adjustments (they’ll spend less time parked in front of their Macs, too). However, if a picture is in really bad shape, only a Levels adjustment can save it.

Figure 5-13. By watching how the histogram data changes as you scoot the Light and Color smart sliders around, you can balance the dark and light tones in your image. The histogram for the original, unbalanced shot is shown here on the left (you can tell that the image is too dark because most of the data is bunched up on the left side of the histogram), and the adjusted version is on the right. Without watching the histogram, your corrections are just guesswork.

The Light adjustment, as you might suspect, affects the lighting in your image. Dragging the Light smart slider to the left darkens your picture and dragging it to the right lightens it. That sounds simple enough, but in order to darken or lighten your picture, the Light smart slider actually adjusts six incredibly powerful sub-sliders that are usually found only in pro-level image-editing programs (which makes it impressive that Apple put these controls in a free app). Here’s what all those sub-sliders do (if you need a refresher on how to summon them, see Using the Adjustments Panel on a Mac [Mac] or 124 [iOS]):

On a Mac, if you don’t like the effect you’ve created by dragging the Light sub-sliders around, simply click Reset Adjustments at the bottom of the Adjustments panel. On an iOS device, drag the slider back to its original centered position or click Cancel (as you learned on The Mighty Histogram, the latter method nixes all the changes you’ve made during that editing session and takes you out of Edit mode).

This smart slider lets you make the colors in your pictures more or less dramatic. If you drag the Color slider leftward, Photos tones down your picture’s colors; if you drag it all the way left, the colors disappear and you end up with a black-and-white photo. To boost the colors in your picture so they stand out more, drag the Color slider rightward (Photos adds a bit of color contrast, too). Here’s what the Color adjustment’s sub-sliders do (see Using the Adjustments Panel on a Mac if you’ve forgotten how to display them):

Figure 5-16. Using Photos’ powerful Color sub-sliders (Saturation, Contrast, and Cast), you can make the colors in your images pop off the page (notice the difference in the blues and greens in this shot). Dragging the Cast slider to the left also cooled down this image a little.

When you want to make a big difference in a picture with one simple change, you can’t beat converting it from color to black and white. This Ansel Adams approach doesn’t just evoke nostalgia, it also puts the focus on the subject in a powerful way, as Figure 5-17 shows. Going grayscale also lets you salvage an image that you can’t color-correct, or beautify a subject whose teeth need whitening (which you can’t do in Photos) or whose skin needs retouching (Retouching Images). Those problems and others all but disappear when you enter the realm of black and white.

If you click anywhere on the Black & White smart slider, Photos dutifully drains the color from your picture. Drag the slider left or right to adjust contrast and produce the look you want. (On an iOS device, you have to tap B&W, and then tap the slider that appears.) Dragging this slider leftward pushes the histogram data rightward, which lightens the picture and gives it an ethereal look (great for camouflaging uneven skin tones in portraits). Dragging this slider rightward pushes the histogram data leftward, which produces a darker and more dramatic feel (you may want to avoid this on portraits, as it emphasizes undereye shadows). Here’s what the Black & White sub-sliders do (flip back to Using the Adjustments Panel on a Mac [Mac] or Using the Adjustments Panel on a Mac [iOS] if you need help displaying them):

Figure 5-17. The high contrast of the bricks in this portrait makes it a great candidate for converting to black-and-white. If your subject has noticeable light reflections in their eyes, drag the Neutrals slider rightward to lighten them so their eyes sparkle even more!

Much like sharpening a knife in your kitchen accentuates its edge, sharpening an image in Photos accentuates the high-contrast edges it contains (that is, places where light and dark pixels meet). This adjustment works by lightening light pixels and darkening dark pixels wherever they appear next to each other.

Photos sharpens your picture the second you add this adjustment to the Adjustments panel—you don’t have to click its Auto button. Before you grab the Intensity slider and increase the sharpening, set your image to 100% zoom level using the zoom slider (Adjusting Your View: Zooming and Scrolling), and then reposition your picture so you’re seeing the most important part (say, the eyes). Next, slowly drag the Intensity slider rightward. Keep in mind that photos with a lot of hard lines—landscapes, architecture, and such—benefit from a stronger dose of sharpening than portraits, where a lot of sharpening makes the subject’s pores leap out of the photo. And if you’re going to print the picture, it’s okay if it looks a little too sharp onscreen because the printing process will soften it a little. It’s a good idea to sharpen all the photos you’ll print or use in book, calendar, and card projects (Chapter 9). Otherwise, they can look unnaturally soft.

In addition to the Intensity slider, the Sharpen adjustment sports two other powerful sub-sliders, which are visible in Figure 5-18 (see Using the Adjustments Panel on a Mac if you need a refresher on how to display them). Here’s what they do:

This adjustment is great for accentuating the details in your image without over-doing contrast. It adds clarity by adjusting contrast in the midtones, which is where many fine details reside.

Photos applies some definition to your picture the minute you add this adjustment to the Adjustments panel (Advanced Adjustments tells you how to do that). Dragging this slider to the right can make a flat or hazy picture look sharper, though its impact isn’t the same as using the Sharpen slider (which affects all the tones in your image). You’d be hard-pressed to find a photo that won’t benefit from at a little extra definition (see Figure 5-18)—except for portraits (nobody looks good with extra definition in their skin!). This adjustment is a one-trick pony; it doesn’t have any sub-sliders.

Figure 5-18. Left: Behold, Photos’ incredibly powerful sharpening controls. Right: As you can see, the Definition adjustment makes this picture look even sharper. For example, notice how much more detail you can see in Sherlock’s fur and nose area.

In photography circles, the term noise refers to graininess in your images—the colored or grayscale speckles produced by shooting in low-light conditions or at a high ISO, your camera’s light-sensitivity setting. (Typically, any ISO above 800 puts you in the noise danger zone.) This slider reduces noise by blurring your picture, so use the minimum amount necessary. Also, be sure to view your image at least 100% zoom level when using this slider and keep your eyes glued to any dark areas, which is where noise lives. This adjustment doesn’t have any sub-sliders.

If you’ve ever seen a picture with a softly darkened edge, you’re familiar with vignettes. (Technically speaking, vignettes are pictures whose brightness fades from their centers to their edges). Adding a vignette is a great way to downplay a distracting background or accentuate your subject, as Figure 5-19 shows. You’ll likely use this slider on every portrait you take.

Figure 5-19. Rare is the portrait that won’t benefit from a dark-edge vignette! Adding one gives your portrait a classy and elegant final touch, and helps tone down a distracting background.

When you add this adjustment to the Adjustments panel (Advanced Adjustments), Photos applies a vignette at 0.75 intensity, though you can adjust that with Strength slider. Dragging rightward increases the amount of dark shading, and dragging leftward decreases the shading. Avoid dragging this slider left into negative numbers; if you do, the edges of your picture turn oddly light. Here’s what the Vignette adjustment’s sub-sliders do (to display them, put your cursor over the word Vignette and click the down-pointing icon that appears to its right):

This adjustment lets you change the color of light in your shot. Different kinds of light—fluorescent lighting, overcast skies, and so on—lend different color casts to pictures. White balance, both in Photos and in your camera, is the setting that eliminates or adjusts the color cast according to the lighting. But isn’t that what the Color adjustment’s Cast sub-slider does, you might ask? Yes, but Photos’ White Balance adjustment is far more powerful.

When you first add White Balance to the Adjustments panel, you see an eyedropper and a menu. The menu controls the method this adjustment uses and the eyedropper lets you tell Photos which part of your image to analyze.

There are two ways to use Photos’ White Balance adjustment (see Advanced Adjustments if you need help adding it to your Adjustments panel):

Figure 5-21. Adjusting a picture’s white balance can make it look like you took the photo at a completely different time of day—say, at sunset instead of high noon. In this example, both the Temperature and Tint sliders were dragged rightward to warm the photo, which is also handy for warming skin tones bleached white by your camera’s flash.

Congratulations! You’ve arrived at Photos’ most advanced adjustment. When you choose Levels from the Adjustment panel’s Add menu, Photos opens yet another histogram, but this one boasts a whopping eight draggable sliders that give you precise control over the brightness levels (hence the adjustment’s name) of the tones in your image. You can adjust the brightness levels in just the darkest shadows, just the midtones, just the lightest highlights, in the tones between shadows and midtones, and in the tones that fall between midtones and highlights. You control all of that in the Levels RGB histogram—the one that shows the red, green, and blue, graphs superimposed on each other—or in each of those channels individually. You also get access to the Luminance channel, which is described in a sec.

As you drag the Levels sliders around (which you’ll learn how to do later in this section), the histogram you learned about on The Mighty Histogram changes to reflect the adjustments you’re making with Levels. For example, if you need to widen your histogram to more evenly spread out the tones in your image, you can tweak the Levels sliders as explained in this section and watch the other histogram widen as you do so.

The Levels adjustment doesn’t have any sub-sliders, but it does have a menu that lets you access other histograms. To see it, point your cursor at the Levels adjustment, and then click the icon circled in Figure 5-22.

Figure 5-22. Photos gives you several different histograms to view and adjust. When you click the Levels adjustment’s Auto button (visible here), the only histogram that’s affected is the one you’re currently viewing.

Your histogram choices are:

As described earlier in this chapter (The Mighty Histogram), if the data in your histogram covers a good chunk of the territory from left to right, then your image has a good distribution of dark and light tones. However, if the data is bunched in the middle or to one side, or if there’s a gap between the edges of the histogram and where the data begins, spreading the data out a bit can dramatically improve your picture.

There are two ways to spread out the data: You can have Photos automatically adjust the levels in your histogram of choice by clicking the Auto button that appears when you point your cursor at the word “Levels,” or you can do it manually by dragging the Levels sliders labeled in Figure 5-23 (again, in your histogram[s] of choice). Adjusting these sliders yourself will give you the best results, though you can always start with Auto adjustment and then tinker with them.

Figure 5-23. These are the eight Levels sliders you can use to fix your images. Look closely and you see the blacks, grays, and whites sliders are filled with their respective colors. Handy!

To really understand Levels, it’s helpful to imagine a numeric grid beneath the histogram that ranges from 0% to 100%, which is the brightness range you learned about earlier in this chapter (The Mighty Histogram). The Blacks slider on the left side of the histogram represents the darkest shadows in your picture and starts out at 0% for pure black. The Whites slider on the right side, which represents the lightest highlights, starts out at 100%—pure white. To give your image the greatest possible tonal range and contrast, move these sliders so they point to wherever the data starts to slope upward (at the foot of the histogram mountains, so to speak). In other words, if there’s a gap between the Blacks slider and the left end of the histogram data, drag that slider to the right. And if there’s a gap between the Whites slider and the right end of the histogram data, drag that slider to the left.

When you move the sliders, Photos adjusts the image’s tonal values accordingly. For example, if you drag the Whites slider left to (an imaginary setting of) 85%, Photos changes all the pixels that were originally 85% or higher to 100% (pure white). (Translation: They get brighter.) Similarly, if you move the Blacks slider right to (an imaginary setting of) 5%, Photos darkens all the pixels with a brightness level of 5% or lower to 0% (pure black). Photos also redistributes the brightness levels between 5% and 85%, boosting the image’s overall contrast by increasing its tonal range. If you watch the histogram at the top of the Adjustments panel (the one you learned about on The Mighty Histogram), you’ll see it widen as you change the sliders in this way. Figure 5-24 shows what a difference this can make.

Figure 5-24. As you can see, a Levels adjustment can do wonders for a picture’s overall lighting and contrast. Notice the big gap on the right side of the original histogram (left); that indicates that the picture has no real highlights. By dragging the Whites slider inward, the whole image gets lighter (technically speaking, darker tones are remapped to lighter ones).

Next, turn your attention to the Shadows and Highlights sliders—they control the tones that fall between black and 50% gray, and between 50% gray and white (respectively). They only appear when you point your cursor at the Levels histogram, and they give you immense control over the entire range of midtones, which is where your picture’s fine details live. For example, if your picture’s shadows look dark, lighten them by dragging the Shadows slider leftward. Or if your highlights look too light, darken them by dragging the Highlights slider rightward. Dragging these sliders doesn’t affect the image’s black or white point, which lets you retain details in the darkest shadows and lightest highlights.

Now focus on the Midtones slider in the middle, which controls your photo’s values smack dab in the middle between 0% and 100% (or rather, 50% gray). Drag it left to lighten midtones or right to darken them. Doing so decreases or increases contrast (respectively) without changing the brightness levels of dark shadows and light highlights.

If you’re happy with your photo at this point, awesome. If it needs more tinkering, follow the vertical lines attached to the Shadows, Midtones, and Highlights sliders up to the top of the histogram and you’ll notice three microscopic triangles (they’re labeled back in Figure 5-23). These sliders let you control which range of tones is affected when you move the sliders they’re attached to. For example, the Shadows and Highlights sliders normally affect tones that are exactly halfway between the Blacks and Midtones, or Midtones and Whites. By nudging the tiny range sliders, you can specify exactly which tonal range you change when you mess with the Shadows and Highlights sliders. Similarly, the Midtones slider normally affects tones that are exactly halfway between the black and white points, but you can change that by nudging its ranges slider left or right, say, to affect the lightest midtone shadows or the darkest midtone highlights (respectively). However, doing so also nudges the other range sliders because the Midtone range slider has to stay between them.

If all this Levels mumbo-jumbo makes you want to head for the hills, you’re not alone—it’s seriously pro-level stuff. Take a deep breath and remember that it’s impossible to ruin a picture in Photos—if everything goes to heck in a handbasket when you’re dragging sliders to and fro, simply click “Revert to Original” and start again. Also, give yourself time to get the hang of using these controls; just because there are eight sliders to scoot around doesn’t mean you should use all of them on every picture. Generally speaking, use the Blacks and Whites sliders only if there are gaps on either side of your histogram. Use the Shadows and Highlights sliders to darken or lighten those ranges, and then adjust the overall contrast with the Grays slider. Lastly, fine-tune the overall brightness of specific ranges using the Shadow, Midtone, and Highlight brightness sliders.

Whew! You can relax—the hardest editing lesson is now over.