Touching up technique

[Defiant911]

I’ve been painting the hull of my Queen Mary Ship and masked of the various colours. For most part this has work quite well but inevitably there always seems to be a small about of airbrush paint that creeps under the tape. What’s the best method of touching in as brushing usually looks to obvious over airbrushing . Do you just try to mask of the small area in question?
See picture with small black over spray mark on white.

[Mr Bowcat]

Personally I'd mask off on the black line and respray white over the overspray.

[Defiant911]

Personally I'd mask off on the black line and respray white over the overspray.

I have been looking closer and I’m now thinking the whole
Black line is slightly high so I could do with masking the whole side again and extending the white down from the top slightly. Spraying white over black is a bit of a nightmare being such a dark colour. Would it be best to spray a grey primer colour first over the black before re doing the white . Any tips on best way to go about spraying white over black .

[Mr Bowcat]

Covering black is always going to be an issue. Can you strip the paint off (half an inch either side of the current line) then repaint.