A rectangle, fill is #541C87 (purple), 50% opaque.
This transparency against the background is a pretty color.
I want to be able to use this color in other places, on top of other color rects.
So, put a white rectangle (#FFFFFF) behind the purple rect.
You would think this would result in the same color as the purple rect with background behind it!
But no, it is slightly diferrent color.
Why? How to fix? Is there a simpler way to use transparencies without having to put a white rect behind them?