From LoTROInterface Wiki
Sets the blend mode applied to the background color.
The new background color blend mode.
Sets the blend mode applied to the background color to one of the values specified in BlendMode.
|Color||Performs a blend between a new color generated by applying the hue and saturation of the source and the color value of the destination. The new color and the destination color are then interpolated between using the source alpha.||1|
|Normal||Uses the source color value.||2|
|Multiply||Computes a new color by multiplying each color channel by the source color channel and then interpolating between the new color and the destination color based on the source alpha. Multiply will never brighten a pixel.||3|
|AlphaBlend||Overlays the source over the destination using the source alpha to interpolate between the source and destination colors.||4|
|Overlay||Overlays the source over the destination. If the source alpha is zero destination color will remain unchanged, for any other alpha value the source color replaces the destination.||5|
|Grayscale||Compute a new color by copying the max of R,G, and B to all three color channels. This new color is then blended with the destination color based on the source alpha.||6|
|Screen||Compute a new color by multiplying the inverses of each color channel by the inverse of the source color channel and then inverting the result. The new color is then blended with the destination color based on the source alpha. Screen will never darken a pixel.||7|
|Undefined||Specifies no blending.||8|