Quote Originally Posted by Midgardsormr View Post
Setting the dpi higher will not do anything. The only time you'll see a difference by adjusting that resolution is when you print. (Okay, almost the only time. Some programs have an "actual size" button, but its usefulness is dubious unless the program also knows the physical dimensions of your screen.)

Ascension's got it. However, turning a 1 pixel line on an angle probably won't work out so well because the anti-aliasing will just turn it into a hazy blur.
Let's think about this. If you have an image that is 1 inch by 1 inch and you have a resolution of 10px/inch, then one px is 1/10 of an inch. That means the smallest line you can draw is 1/10 inch thick. If you have that same image that is 1 inch by 1 inch and you have a resolution of 1000px/inch, then one px is 1/1000 of an inch, and the smallest line you can draw is 1/1000 of an inch thick. So resolution does matter in how fine a line you can draw. Remember, dpi and resolution are not the same thing. dpi only matters in printing. Resolution matters on the screen. They are connected, but not the same. Or do I have this all wrong?