In comes the dried paint technique I have used for seat belts
This involves painting a silicone mat with acrylic craft paint using a soft brush. When the paint dries it can be pulled from the mat and is a layer of paint that is flexible This is then cut into strips and applied to the model like a decal. A light application of windex over the paint stripe, once it is placed, will active and soften the paint. Wait for 20 minutes and then gently press against the paint with a rubber eraser. This will set strip in place.
I have used this technique for making flags, seat belts and now pin striping.
In the picture above the first layer of dark blue was painted directly on the model. The red and light blue stripes where strips of acylic paint applied as I have described. Not perfect, but remember this is 1;43 scale and the subject car is small.
The rest of the markings are laser printed decals I applied ,
Cheers
Dan