I hear folks talking about sealing the tape edges with a coat of base color all the time.
Please! think about is a moment. Any paint you apply contains Pigments, Pigments have dimension and mass. This means your Paint dam (build up of paint at the tape line) is going to be MUCH thicker then if you used a CLEAR paint compatable with whatever paints your spraying.
When I'm doing multi color Scale models it's a big help to use a matte or satin clearcoat as a tape edge sealer between color coats.
Be sure to burnish down the edges of all masking before this quick clear application. This ensures the taped edges are sealed to the underlying substrate and provides a minimum edge for build up and prevents seeping, creep or whatever you'd like to call it.
Why matte or flat? Because it flashes off the solvents quicker then gloss. preventing damage to the newly applied color(s) below and drying very very quickly.
For this type operation I normally use Testors dull coat, just because it's what I developed the technique with. Possibly other satin or matte clears will work but I can't say as it's not what i've used. This process works well with old formula Krylon paints, Testors, Pactra, colorworks, Duracolor, Duplacolor, Rustoleum, and lots of other rattlecan "brands". As a matter of fact to date I haven't found a rattlecan this technique hasn't worked with other then New forumla Krylon that doesn't even like itself LOL!!!
How do we remove maskings almost instantly after applying the next coat? 1) By providing pull tabs folded into the tape at specific points. These are usually set-up so they fall behind the forward edge line of whatever masking material your using.
2) Use of tweezers to pick-up your pull tabs.
3) Always pull tapes nearly back on itself as it's being removed, turning the model on a mandrel or paint stand stick away from yourself as you pull the tape off.
Paint Dams:
Every single type and color including clears leave some type of paint dam at the masking edge. These can easily be nearly completely removed with a little wet sanding with an Ultrafine Grey Scotchbrite #7448 sanding pad. used with LOTS OF Water.
I usually work over a 5gal bucket in the basement with a terry towel draped over the open top. Dipping the pad in fresh water to keep it sopping wet as I lightly circular sand the buildup areas. Rinse often with clean water and feel the area as you go. This well result in a completely smooth transition between colors and layers. It's also possible to smooth out hand painted lines and details the same way making your entire painted finish appear to be one flat surface. All thats needed is a coat of polymer (Nu-finish) or wax to keep it shinny and clean