By Chris Malinao
In the last column, we talked about the Tone Curve and how precise it can be in controlling tonal gradations in our image. We specifically focused on the Point Curve (vs. the Region Curve) because we wanted to show its power right away by being able to add points in the curve.
But the Region Curve also has its own usefulness, and you may want to use only that if you wish. We’ll discuss the Region Curve in the third installment of this topic about the Tone Curve, but right now we wish to stay with the Point Curve because we ran out of space the last time.
To continue, the Tone Curve is where you go to—with scalpel precision—to adjust tonal gradations in an image. And the Point Curve (click the bottom right icon if you’re not there) is where you can add points for precise adjustments.
We are working with the Point Curve here. The diagonal line you see is the graphical representation of the tonal range of the image. Even after moving the exposure sliders in the Basic panel, when you switch to the Tone Curve you will always see a straight line as starting point. The left side has the darker pixels and the right side has the lighter pixels. Notice also that there’s a histogram under-imposed behind this diagonal line.
You can click anywhere in this diagonal line and drag it up or down (careful!) and you change how dark or light a region of the image becomes. Up makes it lighter, down makes it darker. A point fixes the tonality at that, well, point, when you are dragging an adjacent point. But notice how the line curves also? That’s how it behaves. Each time you click and drag on the line, it leaves a point. To remove a point, simply double-click on it.
Okay, notice the word “Channel?” Next to that is a dropdown menu where you can select RGB, Red, Green, or Blue. These are color channels. When you’re with RGB, it’s the exposure that changes, exposure being the composite RGB values; you drag up to brighten, drag down to darken.
When you’re with the individual color channels, you’ll be adding colors. With the Red channel, you add red by pulling up, cyan when pulling down on the line. With Green, it’s green up, magenta down. With Blue, it’s blue up and yellow down.
Here’s the cool thing: you can also click on a specific part of the image, on the picture itself, and you affect color tones. But you must click on its Targeted Adjustment tool first, that little round thing at upper left of panel that says “Adjust Point Curve by dragging in the photo” when you hover on it. When you have it, target a point in the image and click-drag up or down and see what happens.
You can easily mess up your image with the Point Curve, that’s its power. But done right, it gives you power and precision. Experiment. Don’t worry about messing up your image, Lightroom after all is non-destructive; you can always step back in History, that panel at left, and start again.
Again, in the Tone Curve panel, we see the word Point Curve and your choices are Linear, Medium Contrast, and Strong Contrast. These are the curve presets, choose to taste. Cool thing is you can make your own. For example, you chose Strong Contrast to start with, then you edited the curve to your taste, and you might be able to use this adjustment again, you can save it. Notice that the words Strong Contrast has changed to Custom, and when you drop down its menu, you see Save… added to the options. Click that and name your curve preset and it will be added to the menu after it has been saved to the Curves folder as an xmp file.
A good example on the use of the Point Curve is to apply a matte finish, like vintage film, to an image like you see in Fig. 1. The black point is pulled up and dragged in to remove darkness in the darker tones. The white point is also pulled down and dragged in to remove brightness in the bright areas resulting in a matte film look. Try it with your own high-res images, as newsprint and low-res screens might not be able to properly render the example given in Fig. 1.
We hope you try the Point Curve and become aware of its power and precision. Next, we’ll talk about the easier-to-use Region Curve and why you would still want to use it. Yes, you will want to use it even after using the exposure sliders in Basic panel. See you again!
Chris Malinao teaches Lightroom as workflow software to photography students at the FPPF (Federation of Philippine Photographers Foundation), a nonprofit organization that offers year-round workshops in Basic Photography, Advanced Photography, Wedding Photography, Strobist Lighting, Food Photography, Photoshop, Lightroom, and other specialty photography workshops. For details, please visit www.photoworldmanila.com.