Particle amount more than should be ?

I’m using an hand painted image texture to drive the density of the particles but it’s not cramming e.g. 1000 particles into the space painted, I have to up the amount of particles to a ridiculous amount. Is this normal ?

Yes it is. The particle do not ‘emit from white’, they ‘hide from black’ so if your emission area is small you should first use a vertex group to define the region of emission. The vertex group should go slightly outside of your hand painted area.

Figured as much, thanks. I used a texture because the weighting gives square-ish results.