TIP: Change blend modes of multiple layers

You can change the blend mode of multiple layers all at once by doing this. Change the blend mode of one layer, say to Multiply mode. Control Click (PC: Right click) on that layer and choose Copy Layer Style. Then select all the layers you want to change to Multiply, Control Click (PC: Right click) on any of the selected layers and choose Paste Layer Style. Even though we don't think of blend modes as a layer style, technically they are, so all the selected layers wil be changed ot that blend mode.