Creating Contrast Masks

It is often desireable to apply certain adjustements to the highlights or shadows of a particular image. One way to do this is to create contrast masks that will mask either the highlights or shadows. The following is a summary of one way to make contrast masks. In this example, the masks are used to apply Brightness/Contrast adjustments on only shadows or highligh areas.

How to make contrast masks in photoshop:

These are the directions on how to make two contrast masks (one for the highlights, and one for shadows).

Each mask will be a channel in photoshop channels.

The mask protects everything in the image except what you want to work on. For example: The highlight mask will allow you to adjust the highlights, but everything else is unaffected.

1) After your image is loaded, open the channels window (go to the top, select Window, Channels): It will show 4 channels RGB, Red, Green, Blue.

2) Go to the top, under "Selection", select All

3) Go to the top, under Edit, select copy

4) Go to the Channels window and hit the little arrow on the top right of the channels window. This opens the options under channels.

5) Select new channel and give the channel the name "highlights" and hit ok (a black screen may appear).

6) Go to the top and select Edit, Paste. This copies a grayscale image into the channel called “highlights”.

7) Go to the Channels window and hit the little arrow on the top right of the channels window. This opens the options under channels.

8) Select new channel and give the channel the name "shadow" and hit ok ( a black screen may appear).

9) Go to the top and select Edit, Paste. This copies a grayscale image into the channel called “shadow”.

10) Now go the channels window and double click on the highlights channel (double click on the small image in the channel window). A window will pop up called "highlights" - Hit OK. This brings up the grayscale image called "highlights".

11) Go to the top and select Image, Adjustments, Brightness/Contrast this brings up the brightness and contrast adjustment sliders.

12) Slide the brightness slider to the left about halfway (approx - 50)

13) Slide the contrast slider to the right about halfway (approx + 50)

Adjust the sliders to get the effect necessary. Your image should look like a high contrast black & white picture. The highlights should be bright white and the shadows should be black.

How much of the highlights are showing on this image will determine how much of the pictures highlights will be affected when you are applying the mask later on.

14) When you are satisfied with the look of the highlights mask, hit OK , go to the channels window and double click on the shadow channel to bring up the shadow channel (double click on the small image in the channel window). A window will pop up called "shadow" - hit OK. This brings up the grayscale image called "shadow".

15) Go to the top and select Image, Adjustments, Brightness/Contrast this brings up the brightness and contrast adjustment sliders.

16) Slide the brightness slider to the right about halfway (approx + 50)

17) Slide the contrast slider to the right about halfway (approx + 50)

18) Hit Ok

19) Now go to the top and select Image, Adjustments, Invert

This gives you an image that looks like a high contrast black & white negative. The shadow areas of the original picture should be bright white.

You now have two channels that contain masks. One for the highlights and one for the shadows. This will allow you to work on either the highlights or the shadows without affecting the other parts of the image.

20) Go to the channels window and double click on the RGB image. This should bring up your original image in full color.

21) Go to the top and select Select, Load Selection a window will pop up where you can select your highlight or shadow mask. Next to the word Channel, select "highlight" and hit OK. It will load the highlights channel. The image will have dancing lines that show the highlight areas that will be affected. Press Ctrl h to turn off the dancing lines.

22) Go to the top and select Image, Adjustments, Brightness/Contrast this brings up the brightness and contrast adjustment sliders.

23) Adjust your brightness and contrast as desired. Notice: This should only affect the highlight areas of the image because you have the highlights mask loaded.

24) After you are satisfied with the look of the highlights, got to the top and select Select, Load Selection a window will pop up where you can select your highlight or shadow mask. Next to the word Channel, select "shadow" and hit OK. It will load the shadow channel. The image will have dancing lines that show the shadow areas that will be affected. Press Ctrl h to turn off the dancing lines.

25) Go to the top and select Image, Adjustments, Brightness/Contrast this brings up the brightness and contrast adjustment sliders.

26) Adjust your brightness and contrast as desired. Notice: This should only affect the shadow areas of the image because you have the shadow mask loaded.