Try this trick:

I assume the walls are all painted and you are just struggling
with the corner.

1. Mask the white wall.
2. Paint a narrow coat of white on top of the mask. Stay off the
red as best you can, trying to only paint an 1/8 - 1/4" on the
red. This coat of white will "bleed" under the tape and seal all
those leak points. Do it twice if you need to. Go do something
else for an hour or two - let this coat of paint dry, at least dry
to the touch.
3. Leave the mask right where it is. Now, paint it red. Allow
to dry. Masking is usually pulled wet, but for this system to
work, allow the paint to dry.


^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Keep the whole world singing. . . .
DanG


"Jeff Ishaq" wrote in message
om...
Hello,

I'm painting a square room, and one wall is to be red; the other
walls
should be white. All the walls are spackled. I am having
trouble
getting a perfectly straight vertical line in the very corner of
the
room, where the red paint of one wall ends, and the white paint
of
another wall begins. The slight protrusion of the spackle makes
this
transition look very jagged, as it also causes paint to bleed
underneath the masking tape when I try to mask off a nice line.

Is there a trick to getting a nice straight vertical line that
transitions from one color to the other in this situation?
Someone
suggested to me 'gum arabic', but I haven't the slightest idea
what it
is, or what I might do with it.

Thanks!
-Jeff