Thank you very much Metaru, this is so delightfull if experienced painter advice to begginer. reason for black is because explosion is very fast.. 0.5sec and happens over scene with lots of thick colors.. I was afraid not to disolve explosion ... if you would not mind consulting.. I provide screenshot on background..

i'd really get rid of that black outline, or at least use a darker color if its necesary to have it. black tends to eat colors whenever its placed in such a small sprite and bright colors suffer the most.