How to paint a room where there is no distinct line where the walls meet the ceiling?

I want to paint my home office a muted, mossy green but have a dilema. The walls curve into the ceiling, meaning there is no distinct line where the walls and ceiling meet. I want to keep the ceiling it's current creamy color but can't figure out how to make it work with darker walls that curve into the ceiling. Currently there is a wallpaper border about half way up the wall. The walls are blue below the border and creamy beige above it, including the ceiling. I want to get rid of the border completely and just have solid colored walls. I have no idea how to accomplish this because of the weird curved wall / ceiling issue. Any similar experiences, solutions and / or creative ideas? Thanks so much!

Just wanted to say THANK YOU so much to everyone who has already submitted answers and ideas to my painting question. You guys are absolutely AWESOME and have given me some really terrific ideas. My only other question now is...can I vote for all of you as "Best Answer" ?! :o) Thanks again!

I would say that you need a moulding or wall paper border to separate the colours. With the curved section, your eye sees it as a continuation of wall and ceiling - meaning you see the wall and ceiling as one surface more or less. If you were just to paint it without a separation... it's going to look funny. Your eye needs a boundary for the new colour to begin.

If I can make a few suggestions... you have one of two ways to do this. One is to put moulding/wall paper border about 12" or so below the curve on the wall. If your ceilings are low, then you would want the moulding/border to be right at the curve. The other way is to put moulding on the ceiling before the curve and bring your mossy green up the curve. If your room is large, the ceiling method may be the way to go, especially if you put up an interesting moulding. If your room is small go the wall route.

Anyway, good luck with this, and I hope this has helped!

Not having a picture of what your room looks like...I think you could tape off the section you want to be the walls with painter's tape to separate the two areas and then paint the walls the one color and the ceiling the other color.

Would adding molding help?

Make a mark in each corner where the curve begins, then ping a chalk line to join them. You want the wall color to end before the curve or you will make the room look smaller.

Accommodate the 'curve' transition with:
--1. Purchase a roller that makes a border pattern (Ivy?)
--2. Hand-draw same idea as above
--3. Blend the colors across the curve that blends the wall and
ceiling: 4 Qt jars with varying blends of both colors should
allow you to paint from darker to lighter while 'feathering'
the 'seams' to make for a blended transition
--4. Bold border to stand out instead of blending the colors:
think either royal purple or mahogany, stripes of varying
widths separated by thin, dark lines to imply depth

try getting a laser level set it at your desired height and go to town, paint till your heart is content. get a level that is a 360 degree.

Obviously you can put painter's green tape around the top of the wall but will the sharp border look good between the two colors?

You could make a narrow band of another color to make the transition better...maybe three quarters of an inch of very light green just below where the curve starts -- or maybe better where it ends and the ceiling flattens out. You'll perhaps get more ideas like this from your paint store staff.

You could buy a band of wallpaper about two inches wide to make the transition look better, though you might not want this. It could go either at the bottom of the curved portion or around the ceiling where the curve flattens out. Green is a retreating color -- try and advanvcing color like red which will look closer than the green -- though this might turn out to be too over the top.

Get a book on decorative painting from your library, and talk to the paint store.

You could also buy plastic stick-on molding and run it around the wall or ceiling if the age of the house goes with this. I think this might be the best way if it works visually. I'd run it around the top of the wall just where the curve is beginning.

Just below where the curve starts, paingters tape a straight line from corner to corner. Paint the wall below the tape the new color. Remove the tape before the paint is completely dry and you will have a crisp line.