Thermoplastic styrene copolymer resin composition comprising: (a1) at least one styrene-acrylonitrile copolymer component A1, (a2) at least one acrylonitrile styrene acrylate graft copolymer A2 as impact modifier, (a3) optionally at least one thermoplastic polymer A3 other than components A1 and A2, (b) at least one transition metal oxide pigment B, (cl) at least one hindered amine UV light stabilizer C1, (c2) optionally at least one UV absorber C2 different from Cl, (d) optionally further polymer additives D, other than components B, C1, C2, and E, and (e) optionally one metal scavenger component E, wherein at least 99.0 wt.-% of the transition metal oxide pigment B consist of transition metal atoms and oxygen atoms.