When making any adjustments to an image in Photoshop, non-destructive editing is key. Using adjustment layers is one step in a non-destructive editing workflow. In Photoshop (CS 6), there are 16 Adjustment Layers. For the purpose of this article, I will focus on three of my favorite.
- Selective Color
- Gradient Map
First – how NOT to do it
For example if you want to apply some tonal contrast to an image. You can use the Levels Adjustment.
With Photoshop open, go to the Option bar at the top, select Image>Adjustments>Levels. A Level pop-up dialog box appears and you can then make your adjustments using the Shadows, Mid-tone, and Highlight sliders, just under the histogram.
Please DO NOT use this method. Once you click that OK button and continue (unless you press Cltr/Cmd+Z) you are effectively working destructively and altering the pixel information to your image permanently! You will lose information you cannot get back later.
Benefit of using Adjustment Layers
This is where Adjustment Layers come into their own and are simply brilliant. An adjustment layer applies color and tonal adjustments to your image without permanently changing pixel values.
With Adjustment Layers, you are working on a separate layer above the image. So that you are not working directly on the image itself. Any edits that you make happen on this separate layer only and they can be altered, duplicated, or deleted at any time and your original image remains unaltered and intact.
Let’s begin with the Levels Adjustment
The Levels Adjustment is probably the most commonly used in order to enhance your image. It modifies the tonal values in an image by adjusting the brightness levels of the shadows, midtones, and highlights independently. This is essentially what gives contrast to your image.
How to apply an Adjustment Layer
Open Photoshop an do one of the following:
- Choose Window>Adjustments and click on the second icon on the top row.
- Click the New Adjustment Layer button at the bottom of the Layers panel, and choose an adjustment layer type.
- Choose Layer > New Adjustment Layer > Levels. Name the layer if you wish (or leave it called “Levels”) and click OK.
Note: Adding Adjustment Layers will increase your overall file size.
Contrast is the difference in brightness between the light and dark areas of an image. Let’s take a look at the Levels dialog box. Under the histogram, you have three sliders that represent the Shadows on the left (0 represents all dark or pure black pixels) the mid-tones in the centre and highlights on the right (255 represents all light or pure white pixels).
In the image below, I moved the highlights slider in towards the left and the Shadows more to the right. Straight away, you can see the overall image has been improved by adding some contrast.
There are also some presets that you can use. It is worth trying them out, especially if you are new to Adjustment Layers and you want to learn. Just return to the default option if you’re not happy with the results and begin again.
Color correcting using Levels
You can also use the Levels Adjustment to color correct your image by going into the the different RGB channels. Personally, I feel the Curves Adjustment is better option for fine-tuning each of the color channels. However, staying with the Levels Adjustment, you can add color and tonal adjustments by using the three eyedropper tools that represent the black, gray and the white points of your image.
Mark the black and white parts of the image
Starting with the Blacks, click on the Shadows slider while holding down the Alt key, and drag it to the right. You’ll see your image turn completely white. Then slowly drag it back to the left until you start seeing black areas in your image. Stop dragging once you see some black areas appear. These are the darkest parts of the image (the shadows), so you know you will have pure black.
Go up to the Tool Bar and select the Color Sample Tool. This is located under the Eyedropper Tool in the fly out menu. Click on the darkest part of the image. It will leave a marker with the number 1.
Now for the Whites, again similar to above, click on the Highlights slider while holding down Alt, and drag to the left. The image will turn black, slowly drag it back to the right until you see white areas appear on the image. Stop dragging once the white areas appear. This is the lightest areas in your image (the highlights). Again, select the Color Sample Tool. Click on the lightest part of the image. It will leave a marker with the number 2.
Adjust tones and color using Levels eyedroppers
Now Click on the black point eyedropper (circled below) in the Levels dialog box, it’s the first one at the top. Go over to the image and click on Marker 1. Select the white point eyedropper (circled below) in the Levels window, it’s the bottom one, and click on Marker 2 on the image. Now the color and tonal areas of your image have been easily adjusted.
#2 Selective Color
This brings me on to the next Adjustment Layer, Selective Color. This is a fantastic adjustment tool for color, especially where skin tones are required. You can really get a more accurate result by simply adjusting the individual sliders to the right or left for each of the colors and seeing the effect as you go. It’s that easy.
Open a Selective Color adjustment layer the same way you did for Levels by doing one of the following.
- Choose Window>Adjustments and click on the second last icon on the bottom row.
- Click the New Adjustment Layer button at the bottom of the Layers panel, and choose Selective Color layer type.
- Choose Layer > New Adjustment Layer > Selective Color. Name the layer if you wish, and click OK.
You will see a box like this (screenshot to the right). Play with the sliders until you get the effect you desire. You can change from red to a different color by clicking the “Colors” pull-down menu and adjusting each separately.
#3 Gradient Map
Last but not least, my third favorite, the Gradient Map Adjustment Layer. Gradient maps convert your image to grayscale and then replace the range of black, gray, and white tones with a gradient of your choice, in effect colorizing your image. You can use two or more colors. Some really wild effects and so many different possibilities are available with this tool.
Add a Gradient Map adjustment layer as you did with Levels and Selective Color.
The Gradient Map Adjustment comes with some amazing presets. The Photographic Toning presets are impressive and definitely worth trying out.
If you do not see these options you can load more presets. Click on the down arrow next to the gradient, then click the little gear icon to get a pull down menu with more presets you can load. Select “Photographic Toning”.
It will ask you if you want to replace or append. Click OK to replace all the existing presets, or click Append to add them. Add as many of the presets from that pull-down list as you like, or swap them out by clicking OK to keep the selection smaller.
You can also reverse the gradients, and adjust the opacity of the layer as well as the blending mode for even more options.
Do you use Adjustment Layers in Photoshop? What are your favorites? Please leave a comment in the section below.