Is that an ink flow? Generally those are over black, if so, I would attempt building an alpha for it. One effective way to do that is with the handy little “Unmult” plugin. It’s free, you can find it at the bottom of the page here:
https://www.redgiantsoftware.com/products/free/
If that isn’t a black background, but a white background, I would probably use the Keying > Luma Key effect and “Key out Brighter”, that will remove a white background.
After that, I would apply a blending mode.
One other thing that will sell an effect like that is to duplicate the video, make a precomp of the duplicated video, desaturate it and increase the contrast.
Then to your ink layers add Distort > Displacement effect and displace a tiny amount. It will look like the ink flows are being affected by the bricks in the wall.
Johnny Cuevas, Editor
Thinkck.com
“I have not failed 700 times. I have succeeded in proving that those 700 ways will not work. When I have eliminated the ways that will not work, I will find the way that will work.”
—THOMAS EDISON on inventing the light bulb.