The new system of having particles broken up into individual textures files per frame does no longer support transparency of textures. Before 1.14 update it was possible to have semi-transparent textures of particles. Now in 1.14+ when trying to make particles semi-transparent in editing program the game renders it either full color or invisible. In this case I wanted to make water splashes from blue to white semi-transparent for my resource pack

I am enclosing my water splash particles from my resource pack and side by side comparison in this bug report for better picture

As a resource pack creator (and possibly others) I would welcome to have support for transparency of textures.