You can make subtle adjustments to the color saturation of pixels on a texture image using the Sponge tool. Sponge works by either increasing or decreasing the color saturation on pixels in the areas you stroke.

Sponge is based off a Hue, Saturation, and Value color model (HSV), where the saturation value for pixels in a texture layer are modified in the areas you stroke.

1. Click the Layers tab to display the Layers window, and set the layer display to Paint.
2. In the Layers window, select the paint layer that you want to edit.
3. In the Paint Tools tray, select the Sponge tool.

   

4. In the Sponge properties window, set the Amount property to either increase or decrease the saturation for pixels.

   A positive Amount value decreases a pixel’s color saturation, while a negative value increases it. The range is -1 to 1.

5. Stroke across the painted texture in the areas you want to affect.

   Color saturation for the pixels is modified in the areas that you stroke. Hue and Value are not affected.

   You can easily reverse the effect of the tool by pressing the Ctrl key as you stroke. That is, if the Amount property is currently positive, it will be temporarily set to the inverse value when the Ctrl key is pressed. Stroking repeatedly in the same area on the texture image causes more build up of the saturation or desaturation effect.