Depends on the size of the pattern. If you're using something like a 10 x 10 pattern then when you scale it up for a larger spacing then you get little gray parts. The fix for that is to make your own pattern. Make a new document that is 1 inch by 1 inch, create a new layer, use a pencil of size 1 to 3 and draw a line down one side and across the bottom. Hide the background then Edit- Define Pattern (in photoshop)