How to Correct an Image With the Levels and Shadow/Highlight Command

In this tutorial I will show how to correct the color and lighting of an image using the Levels and Shadow/Highlight command. As I will demonstrate, using these commands will give you greater control and better results than just the Auto Adjustments commands that come with Photoshop.

The image I have chosen for this tutorial is a photograph I took of a young porcupine several summers ago:


I had taken dozens of photographs of this porcupine and this one image was the perfect pose. However it was back lit from the sun bouncing off Gastineau channel in the background so the light is very harsh creating a lower contrast image and a greenish yellowish cast. I would like to correct this effect.

When you first start using Photoshop you might adjust your photos using one of the Auto commands. Here is the original photograph applying the Auto Level command - Image -->Adjustments -->Auto Levels or Ctrl + Shift + L :


As you can see, the Auto Levels does improve the contrast, but there is still is a yellowish greenish cast to the image. Let's see what Auto Contrast does.

Here is the original photograph applying the Auto Contrast Command - Image -->Adjustments-->Auto Contrast or Alt + Ctrl + Shift + L :


With Auto Contrast there doesn't seem to be any change at all from the original photograph. Next let's try Auto Color.

Here's the original photograph applying the Auto Color Command - Image -->Adjustments -->Auto Color or Ctrl + Shift + B :


Auto Color adjusts the color somewhat, but it still has a yellowish cast. What I would like to do is tone down the yellowish greenish cast, bring out the blues of the Gastineau channel in the background as well as some red tones. I would also like to add some contrast to this image.

With the exception of Auto Contrast, the Auto Commands did improve the quality of the image. You might say that it looks pretty good. However, you can get better results using the Levels command. The Levels command will let you edit individual color channels as well as shadows, midtones and highlights. To access the Levels command, select Image --> Adjustments --->Levels or press Ctrl + L:


Starting with my original image I am going to press the Auto button on the right hand side of the Levels window. This will give the image some auto correction on which we can do further correcting. The result is nearly identical to using the Auto Levels function. Next I'm going to reduce the greenish yellowish cast in the photo by selecting the Green Channel from the drop down Channel box. This will let me isolate the green values :

You adjust the shadows, midtones and highlights input values for each Channel using the black, grey and white slider triangles under the histogram box. You can drag the triangles using your mouse, nudge by selecting the number directly beneath the triangle and using the arrow keys or directly entering a value in the number box. For my image I raised the black (shadow) triangle to 11 and then reduced the grey (midtone) triangle down to .97, which reduced the greenish cast and brought out some red tones.

I Then selected the Blue Channel from the drop down box to adjust the blue tones. I adjusted the white Input triangle, which lowered the highlight input value to 206. This brought out some of the blue in the Gastineau channel in the lower left of the image. When I was finished, I clicked the OK box to save the changes. Here is the result:


With Levels, I am able to correct the color cast and bring out blue and red colors in the image. Here is a side by side comparison with just the Auto Levels command (click on image to enlarge):

As you can see the Levels command provides a better result than just the Auto Levels.

But I'm still not done with this image. I'd like to reduce the harsh backlight and lighten the face of the porcupine. This is where the Shadows/Highlight command becomes useful.

Go to Image --->Adjustments--->Shadow/Highlight to open the Shadows/Highlights command. A dialog box should appear. Click the Show More Options box at the bottom.

The Shadows amount will be set to 50%, which will lighten the image. Set the amount to 0% to display the original shadow amount. First I want to lighten the face of the porcupine a little. I don't want to lighten it too much so I adjusted the Tonal Width for Shadows down to 30%. The Tonal Width determines the range of values that is considered to be shadows or highlights. I then increased the shadow amount to 10% to lighten the shadows on the porcupine's face to bring its face out. Next I increased the Highlights amount to 70%, which greatly reduces the harsh backlight. Here is the end result:


Here is a side by side comparison with my original image (click on image to enlarge). What a difference!