by Julieanne Kost
To add a color wash to multiple layers, create a new layer and fill it with any color (we will hide the color in a minute but you need the layer to be filled with something in order for this to work). Click the “Add a Layer Style” icon at the bottom of the Layers panel and choose “Blending Options” from the list. In the Layer Style dialog, in the Advanced Blending area set the Fill opacity slider to 0 (zero). Click Gradient Overlay to display it’s options, Set the Blend Mode to Color and choose a gradient preset (by clicking on the small downward facing triangle to the right of the gradient) or create your own (by clicking in the gradient area and using the Gradient Editor). Of course you can always experiment with other blend modes such as Soft Light, Hue and Multiply, Color is simply a starting point.