I haven't tried this myself, but one tip is to put the tape on then paint over it with the original paint. That's supposed to create a seal that will keep the new paint color from seeping through.

I saw a trick on an episode of Colorsplash, with David Bromstad, that I will never forget. Danielle Hirsch used painters tape, but then along the edge of the tape, she painted clear glaze to create a seal between the tape and the old paint. Simply brilliant. Sorry that won't help you repair the paint that's already there, but it's a great hack for next time!

i've tried both of the above options and can confirm they work well.

I always have trouble with getting the lines straight. Take a really fine brush and a straight edge and do it by hand. It takes a bit of time but you get a better line. Retaping will probably get you the same result as the first time.

I have tried Kelleyk's method and it works like a charm, whenever crisp lines are essential this is the way to go. rrigg's method sounds basically the same without the hassle of finding the matching color.

Use matte medium to seal the edges, then let dry. It's available in any art supply store.

What Kellyk said; I've tried it.

You need to pain twice - first the colour that's under the masking tape, then the new colour. Masking tape only works if the walls are complete smooth. Walls usually aren't.

To fix this you could a) paint the edges again using said method, or b) correct by hand. I suppose it depends on how large an area you are dealing with?

You could also retape and then paint with a very small brush (an artist's brush for real - I've done it before with little spots) and just touch up the little bits. Seriously. It's a PIA but it might work.

All the comments above help tremendously.

However, it seems that the surface you're painting is not 100% flat. Whenever painting textured surfaces, the tape alone will not fully create a straight line. The simple tape method only works if all of the tape adheres to the wall, which is hard to achieve on a surface like yours because the paint will bleed.

You can also use the thinnest smear of painters caulk on the edge of the tape onto the wall. Same idea as using the original paint but works if you can't find the old paint.

My walls look that pockmarked as well, thanks to years and years of paint layers. I've found the only way to get a clean line and not go crazy is to a) prime properly, b) run a thin pencil line and paint to about an inch shy of it, then c) use a large (8") metal shield to do the actual edge. Sometimes the shield's called a 'paint spray shield' and other times you can find a similar (and sometimes cheaper) version of the same in the drywall/plaster aisle or the concrete aisle, since it's just a really fancy long-sided way to plaster, too.

What's important is the metal edge: line it up with the pencil mark, and then press it into the existing paint, rocking a little so it creates a line. Then use an 1" tapered brush to carefully brush along the line. The slight gouge keeps the paint from running into the unpainted area, plus cuts any bumps basically in half to make up for the uneven surface. One brush loaded half-full will get you about the length of the shield, then carefully lift the shield up and wipe it off on a towel (to make sure there's no paint on its 'clean' side that you might transfer onto the wall), load up the brush, line up with the marks (overlapping slightly with what you've already done to make sure your line remains even), and keep going.

Once I figured that out, perfect lines ever since. Okay, corners still give me trouble sometimes but on a flat surface it makes for perfect professional-looking lines. Which is good, because I think painter's tape has a vendetta against me or something -- it's never worked for me, at all.

Oh, I feel your pain. I had this experience when I repainted our rooms, as well.

I want to publicly flog the person who decided drop-down texture on walls is a good idea!!

A good tip that has worked for me is to run a razor blade along the taped edge before you paint. This creates a channel for any extra paint that runs under the tape to get trapped and it doesn't bleed.

I have painted two full rooms with alternating 6 in stripes from ceiling to floor and it has worked perfectly both times on uneven wall surfaces.

It is a pain, but in the end looks crisp and clean.

use paint and wall caulk! use the blue tape, rug it down on the wall and then smear the white painters caulk on the edge, paint over quickly and remove while wet. The more caulk you use the easier and better the line. You can use this on any texture of wall! I had a professional painter tip me in on this...after I'd paid him to paint my place!

Just finished painting my bathroom wall - checkerboard style with squares in multiple colors. Perfect lines with no bleeding. I've done several paint jobs requiring a clean paint line and have found the easiest and most effective to be the original idea suggested by kelleyk. My house's 1973 walls are anything but perfectly flat and yet I get straight lines every time! Good luck!

AT, please get rid of the spam comments!

I've also used the 'sealing' trick, people are right that it works on flat surfaces. But upclose your walls actually look interesting, why not accept and keep it. It will be worse if it's almost perfect but not quite.

To fix it now that it is done - use a tiny, tiny paint brush to fix it. I had friends that had this problem, he painted miniatures, so I borrowed a brush and fixed the lines while they argued about why the tape didn't work.

I agree with Cally. I painted a black chalkboard wall that met on outside corners with two white walls, and no matter how hard I tried, the edge where the two colors met bled over slightly. After trying to touch up the black, and having it bleed onto the white, and then touching up the white and having it bleed onto the black, I grabbed a small watercolor brush and meticulously touched it up that way. It will actually take less time than trying to figure out another solution, guaranteed.

Painter's tape and glazing medium, when you paint initially, it works on all surfaces (walls, furniture, canvases) and I'm always surprised when that tip's not included in any 'how to' basics on painting. Only a pro who's been painting a very very long time can get straight lines without painting/glazing - the rest of us need the help of tape!. Glazing works better than using the regular wall paint, imho, and a small container of glazing medium is usually under $8.

In your case, you need to let any fresh paint job cure for at least a week (so you don't lift your fresh paint when you tape), then tape off so that you expose only the problem area. Glaze the area (going over the edge of the tape) and then paint. This will unfortunately change slightly the size of the area you painted but it's the only real way to post-fix a painting problem. Otherwise it's 'repaint the whole wall'.

In regard to the comments suggesting the use of clear glaze, is this something that you buy at a home improvement store? I mentioned it to an employee at Home Depot and they had no idea what I was talking about.

Tape on both sides so that one inch of each color is exposed. Now lightly spray paint a transition color in the two inch wide area, lightly enough so no paint runs.

This turns a mistake into a design element.
On the section where you had blue/white,
you now have blue/light blue/white
the light blue area being a two inch wide stripe

or dark grey/light grey stripe/white

definitely easier than repainting with a small brush and better looking as well

have fun

A good quality artists flat brush, the paint color to repair, and lots of patience.

@elker62: I've seen a similar method by a professional painter with a flat head screwdriver. Not as sharp, but you're less likely to cut yourself.

I've used Shur-Line's Edge Painter, which is a small rectangular pad that fits into a plastic holder. It does a straight 4" line. I originally bought it to touch up along the ceiling when I had overlaps like the ones shown here. Now when I paint, I put down blue tape AND do the edge roller. Not 100% perfect, but works pretty well.

I have the same problem. My husband and I painted vertical stripes 6" wide along a ten foot wall using none of these preventative measures. Now we have 11 eight foot tall stripes that have bled under the tape all the way down the stripes. Our idea for correcting this is to use a putty knife and possibly a modeler's paint brush, and carefully go over where it bled. My concern is that if we line up the putty knife wth the line of where the tape was that is also at the edge of our stripe, if we're not careful enough we will paint the white unevenly. I also believe there is no way my husband will put up tape again, even to fix the problem. Any thoughts on this?