Colour Splitting?

[murch2001]

Hey guys, I'm quite a newbie when it comes to Photoshop, i have some experience but not a great deal.

If you draw a line, you would expect the line to be one continuous line right? As in, all one colour. I'm just wondering if anyone know's why When i do that, it ends up splitting into seperate colours, as if its trying to blur out the line? Ive given an example in the link below?

Anyone know how to stop this?

http://i123.photobucket.com/albums/o302/murch2001/colour-splitting.jpg

 

[murch2001]

So i'm guessing no-one has a clue?

 

[mfox]

What layer is the line on

 

[murch2001]

It doesn't matter what layer its on, its on Every layer. It happens with everything, it somehow manages to blur out both the bottom and top line of a box, line, etc. And i really don't know Why?