For people who really love to take pictures, the process doesn’t end when the shutter clicks. Photo editing matters, too. And Mac-owning photography enthusiasts have a powerful set of editing tools in the updated Photos app that’s built into Apple’s latest operating system, macOS High Sierra.

These include Curves, White Balance, and Selective Color. If you have used photo-editing software such as Pixelmator, Polarr, or Photoshop Elements 15, you could find that the Mac Photos app now has everything you need.

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But if you haven’t done much photo editing before, these tools can be confusing to use. I’ll walk you through the basics, below.

To be clear, the revised Photos app wouldn’t win a head-to-head bout with the full version of Photoshop or Lightroom, which professional photographers and graphic designers depend on.

However, for most of us, that’s perfectly okay, says Artur Pietruch, a Consumer Reports camera and photography technical expert. “I hear a lot of people talk about how much they need to buy Photoshop,” he says. “But from what I’ve seen, most people rarely tap into the real power of the app. They just end up wasting $10 per month on a subscription.”

High Sierra was released as a free update in September. In addition to the enhanced Photos app, it includes support for virtual reality, a speedier browser, and a new file management system for all Macs introduced in late 2009 or later. 

Upgrading to High Sierra

If you’re about to upgrade to macOS High Sierra, here’s some basic advice. First, any time you upgrade to a new operating system, it’s smart to first create a backup of your files. This isn’t strictly necessary to have the upgrade work, but it’s great insurance against mishaps.

There are three ways to create a backup for your Apple computer: You can back your files up to another storage device (i.e., an external drive), upload your stuff to iCloud, or use Apple’s Time Machine app to create a disk image.

Next, you’ll need about 5 GB of free space in storage for the upgrade. If you don’t have that available, you may need to move some files off your computer or uninstall apps. 

Then just go to the Mac App Store, find macOS High Sierra, and start the download. Once it’s finished, you’ll find the update file on your desktop or in the Launchpad. Double click on the icon and follow the steps to update your computer.

This process could take a while, so if you’re updating a laptop, keep it plugged into a power source.

Finished upgrading? Good. Now let’s use the Photos app. 

How to Use Curves

The most powerful new feature in the Photos app is Curves. I used it to brighten this image of arctic foxes in the snow.

Usually reserved for more advanced editing software, Curves lets you adjust several parts of a photo at once, with a lot of granular control. To do this, you drag points along a white, curved line that runs through the “histogram,” a graph that looks like something from trigonometry class. As you drag the points up or down, you change the shape of the curve and lighten or darken sections of the picture.

To use Curves, you have to understand histograms. A histogram, which you can see in the image above, shows the distribution of brightness in a photo—a spike toward the left of the histogram indicates a lot of dark pixels in the image, while a spike on the right-hand side indicates a lot of very light pixels.

In this case, the histogram shows that most red tones in the photo are on the dark side, while the green tones are generally brighter, and the blues are brighter still—not surprising, because the picture has lots of blue, daytime sky. But, overall, this isn’t a very bright image.

In this image, I was aiming for a larger change in the midtones and a smaller change to the darkest and brightest portions of the image. To achieve this, I pulled the dot at the centerpoint toward the top left of the histogram. 

The result: The picture is brighter, but I’ve preserved the shadows along with the black of the foxes’ eyes and noses.

That’s just one example of what you can do with Curves. You can add more dots and pull sections of the curve in any and all directions. And you can click on the menu to home in on just the reds, greens, or blues (the primary colors for monitors).

To get the hang of Curves, simply spend some time experimenting.

How to Use Selective Color

The Selective Color tool gives users independent control over each color in the photo. In this case, I used Selective Color to make the green of the trees more intense, or saturated, while leaving the whites of the clouds alone.

Under the drop-down menu, the app gives you a choice of which specific color to tinker with. For more precise control, use the eyedropper tool to select a point on the photo, telling the app exactly what color you want to adjust.

In addition to adjusting the saturation, you can tweak the color itself with the Hue slider, for instance, making a green color somewhat more blue. And you can use Luminance to change the color’s brightness.

The Range slider allows you control the spread of colors to be affected by your changes. Let’s say you’ve selected a patch of blue water with the eye dropper. If you expand the range, you can change every blue in the entire photo all at once—all the blues of the water, the sky, someone’s bathing suit. Keep the range very tight, and you’ll affect only blues that closely match the one you picked.

Selective Color overlaps a bit with another control. You can use a slider under the Color menu (near the top of the list in the image above) to change the saturation of all the colors in the photo at once. But I found the Selective Color tool to be much more helpful in achieving the look I wanted.

Tread carefully, though. Many novices overuse the Selective Color tool and wind up with unnatural looking images. Or they commit one of the most overused clichés in photography: Creating one area of bright color in a sea of black and white. 

How to Use White Balance

The White Balance tool, unlike Curves or Selective Color, was included in older versions of Photos. This is a powerful feature that lets you adjust how warm or cool an image is. I used White Balance to remove a cold, blue cast over this photograph that was noticeable in both the trees and the waterfall.

The tool is very easy to use: Moving the slider to the right makes the image warmer, and to the left makes it cooler.

It takes some practice to start seeing that an image is too warm or too cool, but playing with the tool can help you develop that sense. And it’s easier to get the hang of it with some pictures than with others. Imagine the colors you’d expect in pictures of a New England autumn: warmer, red and gold tones rather than cold ones.

In general, I tend to process photographs as close to what I remember as possible. However, other people may choose to add a warmer tone to make an image more inviting. 

As a final note, all the tools we’ve been discussing include some fail-safes, in case an image you’ve been editing just doesn’t look right.

First, you can click and unclick the blue circle next to a tool’s name to review what you’ve done. For instance, click on the circle next to White Balance, and you can turn off the adjustments you’ve made with that tool.

Or, to view the photo as it looked originally, press and hold the button next to the Revert to Original button in the top left of the window. As the name implies, you can use the same button to just start all over again.