Skills Required :
-Basic Knowledge of Photoshop
-Basic knowledge of Unreal Material Editor
Here is the package and TGA image that I created: Blood.zip
Blood splatter is from CG textures.
So it is likely that you will get a file with a white background. Thats quite useless for making a translucent material in UDK. Cardinal sin #1 for decals is a white background. The reason is when you try to ad an alpha channel to it, you still get remnants of white showing through the semi-transparent parts of the blood.
Like this:
So we need to get it on a black background before we create our merge map so we don't get those white artifacts. We will only need grayscale information in the end, so its quite simple.
First of all, select the layer with your blood splatter on it. Then go to Image>Adjustments>Invert or ctrl+I.
That will give you this:
Now that you have a black background, you can go to Select>Color Range.
