Photoshop Tutorials: Fix Tone and Color with Levels In Photoshop

Step 2: Add A "Threshold" Adjustment Layer And Use It To Find The Lightest Areas In The Image

We're going to begin our tonal and color correction with the highlights (the lightest areas in the image). Before we can correct them though, we first need to find them. Fortunately, finding them is easy thanks to Photoshop's Threshold adjustment. Click on the New Adjustment Layer icon at the bottom of the Layers palette:

Then choose Threshold from the list of adjustment layers:

This brings up the Threshold dialog box. Click on the slider at the bottom of the dialog box and drag it all the way to the right. You'll see your image turn completely black. Then, begin slowly dragging the slider back towards the left until you start to see white areas appear in your image. Stop dragging once the white areas appear. These areas are the lightest areas in your image:

Step 3: Place A Target Marker Inside A White Area

Move your mouse into one of the white areas in the image. As soon as you move your mouse over any part of the image, you'll see your mouse cursor turn into the Eyedropper icon. Once you have your cursor over a white area, hold down your Shift key and the Eyedropper icon will turn into the Color Sampler icon. Click inside the white area to place a target marker at that location. You'll see a tiny number 1 in the bottom right of the marker:

We're going to be using this target marker to correct the highlights in the image in just a moment.

Step 4: Find the Darkest Part Of The Image With The Same Threshold Adjustment Layer

We've found the lightest area in the image and marked it. Now we need to find the darkest area, and it's just as easy as finding the lightest area. Back in the Threshold dialog box, click once again on the slider at the bottom and this time, drag it all the way to the left. You'll see your image turn completely white. Then, begin slowly dragging it back towards the right until you start seeing black areas in your image. Stop dragging once you see the black areas appear. These are the darkest parts of the image (the shadows):

Step 5: Place A Target Marker Inside A Black Area

Just as we did with the white areas, move your mouse into one of the black areas in the image. Then, once you have your cursor over a black area, hold down your Shift key and click inside the black area to place a target marker at that location. You'll see a tiny number 2 in the bottom right of the marker:

Step 6: Remove The Threshold Adjustment Layer

We now have two target markers placed in our image. The first one, labeled "1" in its bottom right corner, is marking the lightest spot (or at least, one of the lightest spots) in the image, and the second one, labeled "2", is marking the darkest spot (or again, one of the darkest spots). We don't need our Threshold adjustment layer any longer, so click Cancel in the top right corner of the dialog box to cancel out of it. You'll see your two target markers disappear as well, but don't worry, they're just hiding. We're going to see them again as soon as we add our Levels adjustment layer, which we'll be doing next.