ios - CAEmitterCell color property not working -

i have strange behaviour of caemittercell color property or don't understand right.

i have cell

let cell = caemittercell() 

with content of simple .png file drawn black

cell.contents = uiimage(named: "particle")?.cgimage 

and try change green

cell.color = uicolor.green.cgcolor 

but still rendered black. tried change "render as" property of image "template imagr" in media asset has no effect.

can me understand i'm doing wrong?

ok, case color of initial image: darker image - less color variation have. better use white images particle emitters %)