Particle system format

Hello everyone, i hope i’m not going in the wrong thread, i’m a bit newby !
So, i’m trying to create some environement based on sketch i made, and i need to creat a particle system based on some china ink stain. I struggle on the material used for it as i use some PNG of my stains but the material don’t use it’s transparency.
I already searched but i only found procedual material etc so I wanted your opinion, I bet I’m stuck on something dumb ><…
here is some screenshot and an idea of the project.
[https://image.noelshack.com/minis/2017/16/1492525600-ue4editor-2017-04-18-16-18-03.png

material nodes](https://www.noelshack.com/2017-16-1492525600-ue4editor-2017-04-18-16-18-03.png)

[https://image.noelshack.com/minis/2017/16/1492525427-img-5077.png

Sketch used](https://www.noelshack.com/2017-16-1492525427-img-5077.jpg)
[https://image.noelshack.com/minis/2017/16/1492525599-ue4editor-2017-04-18-16-26-14.png

and project](https://www.noelshack.com/2017-16-1492525599-ue4editor-2017-04-18-16-26-14.jpg)

I think it’s because material is additive and it’s color is ~black. so you add ~nothing to the scene color.
you should try to use translucent material instead.

thanks for your answer!
I tried also in translucent, the problem is that the transparency of my png or targa is not seen… idk if i should manipulate an alpha or someting…
https://image.noelshack.com/minis/2017/17/1493223671-ue4editor-2017-04-26-18-19-45.png
here is an exemple of thoses png i try to transform into a particle.