Start with a decal image. Change the colors in the file, using image
editing software such as PaintShop
The result is to be:
Areas to be retained - white
Areas to be ignored - black
NOTE: It may be necessary to set some areas to an intermediate color. For example, if any area of the image is black or white, you can set it to a color not found in the decal (the white background is set to gray in this example).
Now change all the colors to be retained to white, then change the background to black.
Applying a decal without a mask results in the background appearing in the image.
The decal is applied with an image mask.
