Blur Darkens Alpha Channel

I added a white text effect over a white solid. I turned the text into a compound clip and added a Gaussian blur. The blur caused a darkening around the letter. Blurring a white object on a white background should just remain pure white.

X.jpg (15.87 KiB) Viewed 710 times

This did the same thing using a white circle in a transparent PNG graphic file.

I don't know if this also happens in previous versions but just noticed it in the current beta 17.

Blurring a white object on a white background

I'm trying to think...why would someone do that?

I noticed the darkening on an animated lower thirds effect I had over normal video. I used the directional blur to synthesize motion blur as the text moved out of frame. I noticed a bit of darkening of light areas of the underlying video as the blur moved across it, kind of like a shadow.

My white on white was just to emphasize what’s happening.

Ahhhh...