thank you all about your comments on the banker~
@Motenai_Ronin and MarlFox
The reason why I didn't use pure black and grey on the suit is because it would look a bit dull and less interesting, since there are already not so many colors on him, but I do agree the suit needs to be darker.
I've changed the color of the suit to a purpleish black, since purple is the most close color to black, and also some colors on the head.
Any comment that will help me improve is welcome~thanks a lot~
@Aneko: the program I used was Corel Painter and Photoshop
@Aaronock: thanks
@Ellie: thanks