fine line question

I think you're referring to the edges where the door meets the body panels and the hood meets the fenders, etc. There's a couple of ways to do it:
1. Some people use a small permanent marker and just draw them in.
2. Others make a 'wash' out of paint that won't harm the main body color and just flood the grooves with paint. Let it dry a bit, then buff off the excess with a soft cloth. You might need to dip a small corner of the cloth into the appropriate thinner to remove the excess.

Hope that makes sense. One suggestion though... instead of using 'black' for the panel lines, try using a very dark version of the body color. Black has just so much contrast and can make the whole thing look a little 'toyish'. A dark version of the body color will still give contrast, but not be so harsh. For light colored cars like white or yellow, a medium-dark gray would be better than black.

Use your judgement and build it the way you like...

Murray

Wow, I was going to post a message asking how you get those panel lines (as in the Tamiya catalogue) and now you've answered my question. Thanks. I tried the black first and it looks way too harsh, so I tried a darker version of the body colour and hey presto. Looks great now.

Wow, excellent tip. I, too tried the black and it was too toylike. I did the opposite on a black car. I lightened the body color just a tiny bit and did the seams in jet black. With the shine, you cannot tell the black is not 100% black and the whole car looks great. Also, if you put a glossy clear coat, scrape it out of the seams and it looks less like one piece of plastic but more like seperate panels that are adjacent. Same with planes with metal or glossy finishes. The seams should be less shiny. Good luck.

Paul

I use a Rotring Rapidoliner (~$18 from an art supply store) for black lines -- I have the finest which is 0.18mm!

And I use a extra fine dipping pen, with Private Reserve Ink color Flannel Gray for dark gray, to light gray lines. This take a bit more care, but gives a more realistic finish.

Here is a little more info about these: http://www.naplak.com/modeling/tips/panel_lines.htm