There are several ways to adjust color and saturation in Photoshop. You can completely desaturate an entire image (i.e. take all the color out) by choosing Image > Adjustments > Desaturate. This strips all of the color out of the image but gives you a fairly wishy-washy grey image. This is NOT a good method for converting a photograph to black and white.
You can also choose to work on very specific areas of the image by using the Sponge tool (O). With the Sponge tool you can desaturate or saturate specific areas of an image by choosing a brush tip and then painting onto the image. Here’s how to use the tool.
1. Open a colorful image.
When you change the saturation of a color, you adjust its strength or purity.
2. Select the Sponge tool (), hidden under the Dodge tool ().
3. On the tool options bar, do the following:
- Select a medium, soft-edge brush, about 65 pixels, from the Brush pop-up palette.
- Choose Mode > Desaturate.
- For Flow (which sets the intensity of the saturation effect), enter 50% so that it’s not desaturated too quickly.
4. As I drag the sponge back and forth over the center of the flower to decrease the saturation. The more you drag over an area, the more desaturated the color becomes until it eventually turns gray.
5. As already mentioned, you can also saturate an image using the Sponge tool. This can work well if you want to brighten or make a specific part of a colored image look more vibrant.
Back on the tool options bar, do the following:
- Again select a medium, feathered brush, about 65 pixels, from the Brush pop-up palette.
- Choose Mode > Saturate.
- For Flow (which sets the intensity of the saturation effect), enter 50% so that it’s not Saturated too quickly.
Drag the sponge back and forth over the area you want to add more color to. For the purposes of demonstration, I’m going to over-saturate some of the petals and the stem on the flower.
It’s very easy to oversaturate an image, so that’s why the tool options such as Flow are helpful for controlling how much of an effect there is.