Animate blurred light leaks?

[Marie312601165iyp]

Hello After Effects community,

I'm reaching out for help in creating and animating a "blurred light leak" effect that is commonly seen in modern designs. I've attempted to make this effect from scratch in After Effects, but I haven't been able to achieve the desired result. I've attached some images of the type of blurred light leaks I'm trying to replicate. I am not sure that "blurred light leak" is the good name for this effect but I have attached pictures below: 

Does anyone have any suggestions or tips on how I can create this effect in After Effects? Any guidance or resources would be greatly appreciated.

Thank you in advance for your help!

[Roland Kahlenberg · Accepted solution]

Use a Solid and AE's Mask Feather. The feathering will give you the nice soft edges. To add colors, use the 4 Color Gradient or a combination of Fractal Noise + Colorama. And you can animate the Mask Path too. And try out different Blend Modes + Transform > Opacity. 

HTH

[Marie312601165iyp]

Thanks for your answer it helped me figure out how to make it look how I want!