Case:
Black and white drawings should be converged into pictures that can hold transparency.
White colours should be set to 100% transparency and Back colours to 0% transparency. All colour values in-between should be scaled linear in this range.
Execution:
Back picture: rgb(0,0,0)
White picture: rbg(255,255,255)
Transparency = (r+b+g) / 765
Example of a grey pixel:
Grey picture: rbg(125,125,125)
Case: Black and white drawings should be converged into pictures that can hold transparency. White colours should be set to 100% transparency and Back colours to 0% transparency. All colour values in-between should be scaled linear in this range.
Execution: Back picture: rgb(0,0,0) White picture: rbg(255,255,255)
Transparency = (r+b+g) / 765
Example of a grey pixel: Grey picture: rbg(125,125,125)
Transparency = (r+b+g) / 765 => 0.49