[aulddiy]

I've tried in the past to paint a part of a carving tartan. Never been happy with the result.

How do others tackle this?

[Canopener]

Very carefully.
I'll throw in my 2 cents since I like the idea, but am no great painter. I can tell you right off to forget about tape; it will most likely bleed and cause you a foul moment while you repaint.
I try to figure ahead of time where I might want to paint a design, then carve the wood to suit my idea, in other words, flat, not a lot of bends or folds. Then paint your base coat. Then the only way that has worked for me is to use those long liner brushes and they will take a bit of practice to get used to. Make sure you load the whole brush so you can make long lines without lifting the brush. Then just free hand your tartan pattern.
Good luck.
Jim

[Lynn O. Doughty]

It's really not as hard as you might think. The important thing to remember is which colors are used and how their woven into the cloth. No matter whether the stripes run verticle or horizontally they overlap each other and in so doing create different colors. Start with the lightest color and then paint toward the darker. Say the basic colors are white, yellow, red and blue. Painted in that order will give you white, pale yellow, yellow, orange, red, pink, blue, green, purple. The variation of the colored checks depends on the lightness or darkness of the associated color as it passes over the previous one.