I use layer styles for something like that. Whatever color you want in the middle of the object should be the main color on the layer, then use inner glow for the other color, and that's what will be on the outer edges. Set the options to taste. :)

A clever thing to do, aprilgem! I'll try that... Thanks a million! :)

It worked fabulously! You have no idea the amount of work you saved me from!!! I owe you one.... :) Thanks again! :)

No prob. :)

You can also use the styles' bevel and emboss (inner bevel) and to top it off you can also throw in a texture for good measure. Another technique is to use the gaussian blur filter for a more subtle roundness on a dark background.

or you just do what I do and paint a flat base layer and then use the airbrush to paint the other darker outside bits... us digi comics guys face this hassle every single picture in some way or another :+P

lol, SeanE. :) Easy for you to say -- however, not everyone is as skilled as you are with the airbrush. You can paint perfect rim lighting on a shadowed side, but most people can barely draw a straight line.

I tried all three techniques and they were all successful. I must admit though that, from my point of view, aprilgem's is the easiest, Quest's gives interesting results that can be exploited with certain types of curves, while SeanE's, as aprilgem correctly pointed out, requires stability of hand --which thank God I possess...:) Thank you all for your help.

Didnt quite understand what you meant by certain types of curves and it therefore seemed to me that we werent on the same page thinking that perhaps I misunderstood the original post. So to illustrate I offer these screen grabs.

Ah, of course, now it's getting clear to me! Sorry, Quest, I was mislead by the "bevel and emboss" bit, and thought that would make the technique restricted to "certain types of curves", or situations, if you prefer. Thank you for the trouble you took to demonstrate the full potential of this move to me. I appreciate it a lot! :)