Need help with soldermask and silkscreen

Hello all,

I’m working with Kicad to make some double side pcb. I’m struggling a lot with the software about 2 particular things I want to do.

1/ About solder mask. I have some footprints in my pcb editor (for power leds for example) where the main part of each pad is only for heat dissipation and not at all for mechanical structure. I would like to have a solder mask above almost all the pad and leave just a small piece only for soldering the component. How can I do that ?

2/ About silkscreen, I would like to a have a “negativd” silkscreen. I explain : Now, my silkscreen layer is empty except for some texts and labels around components. I made them in write color. I would to have a completely full silkscreen layer and my labels will be in black. Thus when I will give my files at the board house, the pcb will looks like a white PCB. Is that possible to do that with Kicad ?

Thanks for your help everyone !

Kind regards.