Clean up color problems with the Sponge tool

You may use Photoshop for a number of reasons: to create new graphics, alter existing images, or retouch problem photos. One tool that's often overlooked for retouching is the Sponge tool. The Sponge tool is used to work with color, usually in a photo. Specifically, you can use it to increase and decrease color saturation. Color is a powerful sensation, especially in a photograph, as shown in Figure A. The rich color draws the viewer into the composition. It invites the eye to move from one area to another and to investigate each subject individually. The color unifies the composition as well and gives it a sense of fullness.

Figure A.

Color not only enhances the assets of a photo, but also adds to it in ways composition and texture can't. Color quality is therefore important to the success of the finished work, and achieving it is as significant as choosing just the right location for a shot. When everything falls into place, great! When it doesn't, you can use the Sponge tool to wipe away a variety of woes and worries.

Understanding color saturation

When we talk about color, we generally use three terms: hue, lightness, and saturation. Each describes a different property of an individual color. It's important to understand the differences in the terms to understand the meaning of color.

• Hue. This is the color spectrum value, which is described in terms of red, orange, yellow, green, cyan, blue, violet, and magenta, as shown in Figure B.

  
  

  Figure B.

  

  
  

• Lightness. This is the intensity value, which is described in terms of any hue to black or to white, as shown in Figure C.

  
  

  Figure C.

  

  
  

• Saturation. This is the purity value, which is described in terms of gray to full value, as shown in Figure D.

  
  

  Figure D.

  

  
  

Saturation is the relative mixture, or proportion, of gray to a hue. It's usually expressed as a percent from 0 (fully gray) to 100 (fully saturated). An image that has a saturation of 0 percent appears black and white, as shown in Figure E1. An image that has a saturation range of about 40 to 75 percent appears normal, as shown in Figure E2. An image that has a saturation of 100 percent appears almost artificial, as shown in Figure E3.

Figure E1.

Figure E2.

Figure E3.

Working with the Sponge tool

As mentioned earlier, you can use the Sponge tool to increase and decrease color saturation. Our example shown in Figure F is a little flat, so we'll use the Sponge tool to revitalize this bunch of grapes.

Figure F.

Previewing image saturation and desaturation

The Sponge tool affects the image color in an area as defined by the brush size. But before we get into actually retouching, let's get an idea as to what parts of the image will benefit most from our efforts. A quick way to do that is to preview it using the Hue/Saturation command. To do so:

1.	Open the image you wish to work with.
2.	Choose Image Adjustments Hue/Saturation.
3.	Move the Saturation slider to +55 or so when the Hue/Saturation dialog box opens, as shown in Figure G. Our result is shown in Figure H1. After moving the slider back and forth several times, we noticed that the grapes on the top of the bunch could benefit from an increase in saturation. Figure G. Figure H1.
4.	Move the slider to the left and see if anything looks better with a
little less saturation, say to about -55, as shown in Figure H2. The leaves in our example appear more natural and, when desaturated slightly, will help to focus more attention on the grapes. Figure H2.
5.	Close the Hue/Saturation dialog box by clicking Cancel when you're done.

Choosing tool settings for the Sponge tool

Now that we have an idea of what areas we want to work on, let's begin using the Sponge tool. Because it isn't a good idea to work directly on the original or Background layer, let's make a duplicate of it. If we mess up the duplicate, we'll can simply delete it and make another one.

1.	Click on the Layers palette's pop-up menu and choose Duplicate Layer.
2.	Enter Retouch in the As text box when the Duplicate Layer dialog box opens and then click OK.
3.	Choose the Sponge tool from the Toolbox.
4.	Choose a brush size from the Brush Preset Picker on the tool options bar, as shown in Figure I. You should choose a brush size that allows you to easily paint within the area you want to work on. A soft, round 100-pixel brush works well for our example. Figure I.
5.	Choose Saturate from the Mode dropdown list.
6.	Choose about 20% from the Flow slider by moving it to the right until the value appears in the text box. Leave the Airbrush feature deselected because we want to work slowly and the Airbrush feature tends to add or decrease saturation at an accelerated rate.

Painting with the Sponge tool

1.

Move your mouse pointer to one of the areas you wish to work with and begin painting with short, circular strokes on small areas, building up saturation as you go, as shown in Figure J on the previous page. Typically, the midtones of an image render best when increasing saturation. So, as you work, work proportionately more with the midtones and less with the highlights and shadows. It may not seem as though much is happening at first, but it's important not to work too fast. Figure J.

2.

Toggle back and forth between the Retouch and Background layers by clicking on the Eye icon on the Layers palette to check your before-and-after progress.

Now that we're done with the grapes in our example, we'll turn our attention to the leaves to slightly de-emphasize their appearance. To do this:

1.	Switch the Mode dropdown list on the tool options bar from Saturate to Desaturate. Remember, if you overdo desaturation you'll end up with black and white.
2.	Set the Flow to 10%, and work as we did in the grape areas, painting with short, circular strokes.
3.	Continue checking your before-and-after progress, until finished as shown in Figure K. Figure K.

Note

For information on how to get even more color from your problem images, see the Problem : Solution "Restore color to underexposed areas" at the end of this chapter.

It's a cool tool

The Sponge tool is a terrific retouching tool you can use to add and reduce color saturation in a photo. At times when natural lighting of a subject is too intense or too low, the Sponge tool can help revitalize an otherwise unusable image. Even in controlled situations, such as in a studio setup, when you think you've covered all the bases, things do happen. What you get isn't what you thought you had, and the Sponge tool can help you avoid the additional work of reshooting the photo.