Blending Modes

Q1:	What is a blending mode?
A1:	Blending modes allow layers to interact or blend with the underlying layers. Choose from a list of blending modes in the Layers palette, each of which will have different results based on the color in the layers.
Q2:	Is there a quick way to change layer blend modes?
A2:	Yes! Make sure you have the Move tool (V) selected and press Shift+ (Plus Sign) to move down the list and Shift- (Minus Sign) to move up the list. Or, you can jump to a specific blend mode by pressing Shift-Option (PC: Shift-Alt) and a letter. For some blending modes, use the first letter of the mode. Here's a list of the letters for all blend modes: N = Normal I = Dissolve K = Darken M = Multiply B = Color Burn A = Linear Burn G = Lighten S = Screen D = Color Dodge W = Linear Dodge O = Overlay F = Soft Light H = Hard Light V = Vivid Light J = Linear Light Z = Pin Light L = Hard Mix E = Difference X = Exclusion U = Hue T = Saturation C = Color Y = Luminosity
Q3:	Why does the blend mode change when I change the color mode of the document? When I change from RGB to CMYK, the layers with blend modes look very different. How do I avoid that?
A3:	The best bet is probably to complete all the editing (including setting blend modes) in RGB mode, make a flattened copy (go to Image>Duplicate and then choose Layer>Flatten Image), and then change the color mode of the flattened document to CMYK (Image>Mode). Note : There could still be some shifts due to the color differences between RGB and CMYK.